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Friday, August 16, 2013

A Starring Role in "Security Theater"

Home Plate for N631S and myself in the DC area is Potomac Airfield (KVKX). It's one of the "Maryland 3" airports (along with College Park (KCGS) and Hyde Field (W32)) that reside within the Flight Restricted Zone (FRZ), a circle (more or less) of airspace with a 14 nautical mile radius surrounding the DCA VOR. (See chart at left, below.)

I fly from KVKX because it is very convenient to my home in Alexandria, VA. Gaining authorization to fly in and out of KVKX (and the FRZ) required a certain amount of jumping through hoops but once that was accomplished the whole program has been, as they say, transparent to the user. Until tonight.

Here's how it works (and I'm going to confine this discussion to IFR operations. VFR has its own idiosyncrasies.) Whether outbound or inbound, I file an ordinary IFR flight plan by telephone through the Lockheed-Martin Flight Service Station (FSS) in Leesburg, using a toll-free number dedicated to FRZ operations. Sometimes the FSS Specialist that answers the telephone is in Raleigh, but that makes no difference.

I go through the normal IFR Flight Plan sequence with the Specialist and then he/she asks me, "Are you familiar with the procedures governing operations in the Washington, DC Special Flight Rules Area and the Flight Restricted Zone?" I then say, "Yes, I am!" The next question is, "What is your PIN?"

All pilots that have been "vetted" to operate into and out of the FRZ and the "Maryland 3" airports have been issued a Personal Identification Number (PIN). When I give my PIN to the FSS Specialist, he/she verifies it against a master list, and if it agrees with his/her list then he/she will (one fervently hopes) enter certain appropriate remarks into the "Remarks" field of my IFR flight plan. Then, when ATC pulls up the Flight Plan as I approach the FRZ (in the inbound case), the remarks make it clear that I am authorized to enter the FRZ and land at KVKX. It all works very nicely. Except when the remarks aren't there.

Which brings us to tonight, over Baltimore. It had been an uneventful flight down from Connecticut, and I was looking forward, as I crossed over the top of KBWI, to getting home. Then, I got a radio call:

  • PCT: "N631 Sierra, Potomac?"
  • Me: "631 Sierra."
  • PCT: "Uh...just to let you know, there's some sort of problem with the remarks in your flight plan and we're trying to work it out...but we may not be able to let you into the FRZ...so you may want to start thinking about an alternate. For now, continue on your heading and maintain 6,000."
  • Me: "...OK...present heading, maintain 6,000, 631 Sierra."

I continued southbound toward the Nottingham VOR (OTT), and thought about options. Easton, MD (KESN) was the best choice if I had to land outside the FRZ. From there I could call FSS and sort out the problem and then it would be a short flight back home. Then:

  • PCT: "631 Sierra, we're not going to be able to let you into the FRZ. Say intentions?"
  • Me: "I'd like to divert to Easton."
  • PCT: "Skylane 31 Sierra, fly heading 160, direct Easton when able."

I turned to the east and started to gather up frequencies and such for an arrival at KESN (see track above, courtesy of FlightAware.com). Just as I had all of that more or less squared away, the controller came back to me:

  • PCT: "631S, we've got it worked out! Turn right to heading 250, descend to 2,000, vectors for KVKX. And for what it's worth from my end, I apologize for all this."
  • Me: "31 Sierra, right turn to 250, down to 2,000, and no apology needed. I really appreciate you folks going the extra mile to get this cleared up."

The remaining 15 minutes of the flight were uneventful. N631S and I landed at KVKX; I put the airplane to bed in the hangar and on the way out I stopped to give Potomac Approach a call.

  • PCT: "Mount Vernon approach."
  • Me: "Hi, I'm the pilot of N631S; there was some confusion about the remarks for FRZ entry on my IFR flight plan and I'm wondering what went wrong."
  • PCT: "It was an FSS mistake. I pulled up your strip and the remarks weren't there. I know you come down every Friday, so I called NCRC (National Capital Region Coordination) and said 'Where are his remarks'? They didn't have the remarks. I got the supervisor involved and I guess he checked the tapes and he called back and said, 'he's OK, he should have the remarks.'
  • Me: "I guess they went back and listened to the tapes from this morning when I filed."
  • PCT: "Yeah, you filed at 12:08(Z), right? That's what they did. Again, I'm really sorry about all this."
  • Me: "And again, I really thank you folks for taking the trouble to get this squared away."

Have I mentioned that I love Air Traffic Controllers? Tomorrow I'm going to give LockMart FSS a call to see if they have any ideas for avoiding a recurrence of the problem.

Saturday, July 27, 2013

Unflappable!

When N631S and I departed KVKX last Monday for the trip north to Connecticut, Bridgeport (KBDR) was reporting a 900 foot overcast that was forecast to improve to 1,500 broken around 9AM local time. There were no NOTAM's related to the ILS, so it looked like a good situation.

By the time we were abeam Atlantic City the overcast at KBDR had dropped to 700 feet and by the time we were over the top of JFK it was down to 300 – which is the Decision Altitude for the ILS Runway 6 approach. But there we were, so we flew the approach to have a look. At 300 feet there was nothing but gray in the windshield and we proceeded to fly the missed approach. Checking back on with New York, we heard the expected, "Say intentions." My reply was "Skylane 31 Sierra would like to divert to Oxford." Oxford was reporting a 900 foot overcast.

The controller said, "Maintain 3,000 feet, fly heading 250, vectors for the ILS 36 approach at Oxford." Which will bring us to the point of the story.

New York vectored us onto the final approach course for the ILS Runway 36 approach and handed us off to Oxford Tower. I checked in outside the Final Approach Fix (FAF) and was cleared to land. As usual, I was flying the ILS with 10° of flaps and about 14 inches manifold pressure. This nicely results in about 95 knots and a 600 to 700 feet per minute descent.

We broke out of the schmoo at about 800 feet; there was the runway. At about 500 feet I pitched the nose up a bit to slow N631S and reached over to move the flap control to the fully down position. And...nothing happened. To my surprise, with the flap control fully down, there was no additional flap deployment at all. The flaps just sat there at about 10° extension.

Oxford (KOXC) has about 7,000 feet of runway and landing with 10° flaps is a non-event. In fact, the landing was excellent...a "greaser" (more on that in a bit). I taxied over to the FBO and tried cycling the flaps. Nothing I did would produce more than 10° of movement. So I waited for the ceiling to lift in Bridgeport (which took about an hour), and flew back down there – executing another non-full-flaps landing on arrival. Which led to the next surprise.

The landing at KBDR was not as pretty as the one in Oxford had been; in fact it was a bit of an 'arrival'. With 10° of flaps deployed and the flap control lever in the fully lowered position, the main gear contacted the runway with a hefty 'thump'...and the rest of the flaps deployed very nicely as I rolled down the runway.

Taxiing to the tiedown, I cycled the flaps up and down and got nothing but 'ops normal'. Lever up, flaps up; lever fully down, flaps fully down. All working the way it's supposed to. Drat! I secured N631S and found Tony the Mechanic in the maintenance hangar. He listened to my story and agreed that there was nothing to be done until the failure showed up again.

So...on Wednesday morning, I went back to the airport, opened up N631S, turned the Master Switch ON, and moved the flap control all the way down. The motor began to run, the flaps deployed to 10° – and stopped! Yay! I promptly secured the airplane and went to find Tony.

"Hey, Tony," I called, "Good news – the flaps aren't working!" This drew a strange look from a couple of other people, and a smile from Tony who said, "Good...we'll pull it in here gently, and look for the problem." I guess that it's only in the world of maintenance that the recurrence of a problem is a good thing and its absence is a bad thing. Pilots and mechanics know perfectly well that the problem WILL return...probably when you really don't need it.

The next morning, Tony reported that the problem was fixed. "I turned the master on, and reached up under the panel and moved some wires and the motor started and lowered the flaps. Aha! Pulled the seat out and got under there. A wire to one of the switches was almost broken but not quite – that's why it was intermittent."

Have a look at the picture. When you lower the flap control, it moves the cam and that closes the 'flap down' switch (green in the picture). As the flaps go down, the follower mechanism rotates the switch mount arm and the position indicator until the switch opens and the flaps stop moving – at the ordered position. (It was a wire to this switch that had failed.) When you're done with the flaps, the cam moves the other way, closes the 'flap up' switch, and the process runs in the opposite direction. They've got clever designers out in Wichita!

So N631S is completely healthy again, I get to land with all the flaps I want, and the fix was easy and fairly painless. One of the joys of curating a 36 year old aircraft, I suppose.

Monday, July 1, 2013

Book Review: "QF32" by Capt. Richard de Crespigny

On last Thursday, the Australian Transport Safety Bureau (ATSB) released the final report from its investigation into the causes and consequences of the uncontained catastrophic failure of a Rolls-Royce Trent 900 engine that occurred 4 November 2010. The engine in question was at the time occupying the number 2 position on the wing of a Qantas A380 climbing out from Singapore.

The ATSB report is a fascinating engineering document. It covers thoroughly the reasons for the engine's detonation, the nature and extent of the resulting collateral damage, and the very fortunate absence of any significant airframe fire. It does not, however, dwell at any length on the actions and performance of the flight crew during the event and its aftermath. That side of the story is told well by the pilot-in-command, Capt. Richard C. de Crespigny, in his excellent book, QF32. (The title is the Qantas flight number on which the incident occurred.) Capt. de Crespigny provides the reader with both a gripping narrative and a satisfying explication of technical detail. In addition to being a master aviator, the Captain proves to be a gifted explainer.

The author allots roughly the first 40% of the book to telling us about his journey from his youth through his introduction to flying, his training and assignments in the RAAF, his progression through increasingly challenging – and rewarding – flying jobs at Qantas, and (I think, importantly) his founding and nurturing of a successful computer software business. It was a journey that brought him, on that November morning in 2010, to the left seat of an Airbus A380 named Nancy-Bird Walton and to the moment when, four minutes after takeoff and passing through 7,400 feet, he heard a double "Boom!...BOOM!"

Thus began an incredibly intense one hour and 45 minutes of managing a dauntingly complex systems troubleshooting process while nursing a crippled airplane that had sustained an unknown level of damage. If you wanted to specify the perfect aviator to put in charge of these tasks you would design Richard Champion de Crespigny. From the perspective of stick-and-rudder aviating, his experience flying deHavilland Caribou STOL transports and Iroquois helicopters gave him familiarity with taking machines to the edges of their aerodynamic limits. And his intimate knowledge of software design and behavior not only gave him the motivation to understand the Airbus computer protocols at a deep level, but also a well-honed feeling for the ways that software systems respond to degradation and damage.

As fortune would have it there were five pilots on the A380's flight deck that morning – the normal crew of two plus a relief Second Officer, a Check Captain and a Supervising Check Captain. When the Trent 900 'grenaded', taking with it numerous ancillary systems, the resulting flood of messages from the airplane's computers, some logical and some not, kept all hands busy. The author admits to reaching task saturation in the midst of this chaos until (as he puts it), "..I had my epiphany. My mind switched."

"I inverted the logic. I remembered what Gene Kranz, NASA's Flight Director, said during the Apollo 13 mission: 'Hold it! I don't care about what went wrong. I need to know what is still working...' We went back to basics and it became easy..."

From that point, the crew focused on assuring themselves that they had a controllable airplane with minimally functional systems that could safely be landed within the constraints of Singapore's main runway. As they made configuration changes for landing, Capt. de Crespigny disengaged the autopilot and performed 'control checks', a military technique for verifying controllability of an aircraft that has suffered battle-damage. This isn't found in any Airbus manual, but it assured the crew that the airplane would be stable down to the runway.

Runway 20C at Singapore is 4,000 meters long. The author's colleagues on board had calculated that in its damaged condition the A380 would need 3,900 meters to stop if the Pilot Flying executed a perfect touchdown. At the end of a long straight-in approach, Capt. de Crespigny did just that and got the airplane stopped 150 meters short of the runway's end. And that was the end of the beginning.

The big Airbus now sat at the end of the runway, surrounded by emergency equipment. Flammable jet fuel gushed from the perforated left wing. The brakes glowed, nearly white-hot at over 900°C. And the Number 1 engine refused to shut down. The flight was ended, but not the danger.

The decision was taken to not deploy the escape slides for evacuation. The environment outside the aircraft was more hazardous than the inside. So the cabin crew stood by at the armed doors and stairs and ground transport for the passengers were called for. About an hour after touchdown, the first passenger walked down the stairs and to the first bus; the last passenger debarked about an hour later. At last, the tension subsided. It was three hours and 39 minutes since the Number 2 engine had exploded.

In the days and weeks that followed, Capt. de Crespigny and the rest of the flight and cabin crews of QF32 were justly celebrated. Honors and awards were the order of the day. But the author candidly and generously shares his experience with post-crisis psychological reactions to the stressful experience. He sought and received professional help with Post-Crisis Management, and after a couple of months returned to the left-seat on the A380 flight deck.

It's very interesting to compare Richard de Crespigny's experience on QF32 with that of 'Sully' Sullenberger, who famously landed Cactus 1549 in the Hudson River (as described in his book Highest Duty) after losing both engines as a result of bird strikes. To the best of my knowledge, Capt. Sullenberger has never mentioned any post-crisis effects, but his crisis was over within about 15 minutes. Capt. de Crespigny had to operate under extreme stress for over three hours. Soaking in adrenalin for that long has got to have some side-effects.

There are numerous lessons to be taken from the QF32 story. One stands out for me, and it is this: When it all goes pear-shaped, only the attention of highly skilled, highly trained, highly proficient professional aviators stands between the passengers and disaster. Richard de Crespigny and his colleagues proved this. 'Sully' Sullenberger and Jeff Skiles proved this. And sadly, the crew of Air France 447 seem to have proven the converse.

"The Office" of an A380 at FL330 over France on a quiet evening. (Photo courtesy Capt. R. Ch. de Crespigny)

Saturday, June 29, 2013

Summer Fun

Yesterday's trip from Connecticut down to the DC area was sufficiently entertaining to warrant a post here. Also, it gives me an opportunity to again express appreciation for the amazing skill and willing team-effort on the part of the controllers who shepard N631S and me along our route and keep us out of trouble. In this instance, particular kudos go to the folks at Harrisburg Approach and Potomac Consolidated TRACON (PCT).

I'd been watching the weather map for several days and the synoptic picture forecast for Friday afternoon wasn't very nice. A cold front associated with a deep trough was approaching from the West and was forecast to stall along the coast on Friday. Conditions would be ripe for lots of convective activity. Thus, the Terminal Area Forecast (TAF) for Washington's National Airport (KDCA) was unsurprising:

TAF AMD KDCA 281852Z 2819/2918 19010KT 5SM TSRA BKN050CB
TEMPO 2819/2820 VRB30KT 2SM +TSRA OVC030CB
FM282200 25007KT P6SM VCTS BKN050CB  
FM290000 27005KT P6SM VCTS BKN050CB 
FM290100 27005KT P6SM BKN050 
FM290400 VRB03KT P6SM SCT130
FM291600 21007KT P6SM BKN050=
I was planning a departure at about 1930Z, so the period of heavy thundershowers (+TSRA) was expected to be over well before my arrival, but the prevailing weather for the whole evening was calling for thundershowers in the vicinity. The TAF's for intermediate locations enroute looked pretty much the same.

I decided to depart anyway, watch the weather carefully, and if necessary, land before things got boisterous and wait it out – overnight if necessary. Despite the highly convective environment, this was "air-mass" weather, not frontal activity. The organized lines of storms accompanying a front defy penetration, while the more scattered weather in store in this case often offers a way through if approached with an abundance of caution, lots of information and plenty of fuel.

Everything was peaceful for the first hour or so, but westbound, passing Allentown (KABE) and approaching the turn to the south onto V39 toward Lancaster VOR (LRP), the NEXRAD display showed that things would soon become interesting. Allentown Approach handed us off to Harrisburg Approach a few miles east of FLOAT intersection. Checking in with Harrisburg, after the normal dialog involving altimeter settings, I asked, "Harrisburg, Skylane 31 Sierra is wondering what weather you're painting along Victor 39 to Lancaster and then south towards Baltimore?"

The controller's reply was, "Everything looks good as far as Lancaster, then there's a band of precipitation, heavy to extreme, from south of Lancaster and to the northeast about 50 miles."

I then asked, "Have you got a work-around for that band? I don't want to go and paint myself into a corner down there."

This drew a "Skylane 31 Sierra, stand by," which meant that I had him thinking about the problem. After a pause of about a minute, the controller came back to me with, "Skylane 31 Sierra, it looks like after Lancaster, Victor 143 down toward the BRINS intersection will keep you clear of the weather. Then you can go direct Baltimore." It was my turn to say, "Stand by." I grabbed the Low Altitude chart from the seat next to me, quickly flipped it open to the panel depicting Lancaster, found V143 (which departs LRP on about a 248 heading) and traced it to the Southwest, and located BRINS. I compared that with the NEXRAD depiction and then pressed the Push-to-Talk switch. "Harrisburg, 31 Sierra likes the looks of Victor 143 after Lancaster. I think that's a plan."

After another minute or two I heard, "Skylane 31 Sierra, you are cleared present position direct to Lancaster, Victor 143 to HYPER intersection, then direct to Baltimore, direct to destination. HYPER is a little further, you'll probably be able to turn toward Baltimore before you get there." I read that clearance back, ending with a sincere "Thanks very much." Looking at the weather depiction and noting that the storm cells were moving to the East, it appeared that I'd be in the clear all the way down V143 – and that indeed proved to be the case.

Harrisburg handed us off to Potomac Approach and N631S and I motored along Victor 143, skirting the Northwest edge of the weather. The Potomac controller gave me the customary amendment to my routing, "After Baltimore, direct Nottingham then direct destination," and about ten miles short of BRINS he gave me a 220 heading, adding, "Turn east direct Baltimore when able. Just let me know when you make the turn." It looked to me like it would be about 20 miles before that would be a fine idea.

I turned N631S toward Baltimore, still in the clear and keeping the weather well off to our left. About 25 miles West of Baltimore, the PCT controller said, "Skylane 31 Sierra, there's some weather moving in to the South of Baltimore; that direct Nottingham route may not work. I'd suggest you tell the next controller you'll need to deviate to the East to stay clear of that weather." I acknowledged that with thanks, and got "Contact Potomac on 119.85."

After checking in with the next sector I requested a left-of-course deviation for weather avoidance. She replied with, "31 Sierra, do you have weather radar on board?" I said, "31 Sierra has a NEXRAD weather display."

The controller then said, "Go ahead and navigate around the weather to the east. Just let me know what turns you're making." I said, "31 Sierra is going to go from present position on a 160 heading for a while, then I'll go direct Nottingham when able." This drew, "31 Sierra, that's approved."

I kept N631S on the 160 heading for 12 or 15 miles, descending first to 4,000 feet and then to 3,000. When I could see past the weather to my right I turned toward Nottingham and said (in response to the controller's query) that I'd like the visual approach to Runway 6 at KVKX.

As you can see from the picture at left, that was a fairly enthusiastic patch of weather off N631S's right wing. The overhanging cloud shelf was pretty dramatic as well.

And here's a half-minute of video recorded in about the same spot:

A few miles to the south, the way was clear for a turn toward home plate and the landing at Potomac Airfield was uneventful. It took about a half-hour to get N631S put to bed in the hangar, and as I was driving off of the airfield the heavens opened and gave forth an impressive deluge, leaving me thinking that timing is everything.

All things considered, the conditions for this flight were pretty challenging. Good on-board weather awareness (i.e., NEXRAD) was a 'no-go' item but the real essentials were a creative and savvy controller at Harrisburg approach who quickly developed a workable re-route, and a couple of smart, and above all flexible controllers at PCT who made it possible for me to complete the trip safely. My profound thanks to all.

Saturday, June 8, 2013

Sidebar!

One of the most enjoyable parts of blog-keeping hereabouts is the curating of the sidebar. That stuff over there on the right, adjacent to the primary content column. The process is fun and it leads to places.

For example...my recent review (rant?) of the biography of Lawrence B. Sperry started out down there in the depths of the sidebar. I had decided to "enhance" the entries on my favorite designers with an appropriate quotation from each, revealed on mouse-over using the HTML abbr tag. A significant amount of Google-aided research failed to provide me with anything memorable from young Mr. Sperry, so I decided to obtain his biography where a nice quote was found. And if you've read the review you know the rest of the story.

I add things now and then. A recent inclusion is the panel showing five recent tweets (or retweets) sourced from my Twitter account. (If you feel like following, that'd be most welcomed.)

So, you're invited to slide on over to the right and poke around the sidebar. If you're moved to offer any comments or suggestions I'd appreciate hearing them (perhaps in a comment on this post). And as always, thanks for stopping by.

Wednesday, June 5, 2013

Book Review: "Gyro! The Life and Times of Lawrence Sperry" by William W. Davenport

It has been my practice to confine book review posts to books that I would recommend to a friend as being enjoyable or instructive – or, preferably, both. In that light, the book I'm about to discuss, William Wyatt Davenport's Gyro! The Life and Times of Lawrence Sperry, is troubling. It does indeed present an enjoyable story. And, reading it does prove instructive...but not in the way one usually hopes. The lesson of the book is that some biographies may be works of fiction clad in a thin layer of verisimilitude, and that a healthy skepticism is a useful tool for the reader of history.

I wanted to learn more about Lawrence Sperry, as the stories commonly told about his brief and colorful life consistently rendered him as a fascinating character. What better approach, thought I, than to lay hands on a copy of his biography? This was readily accomplished with the aid of a used book vendor, facilitated by the good folks at Amazon.com. But very soon after opening the book I encountered a warning sign. What does one make of a biographer who, in the Acknowledgements at the front of the work, says this:
"As in every life that has been lived to the hilt, there are hiatuses, documents that have been lost or suppressed, the ambiguities of reality, questions that have not been answered, problems that have not been solved. In such cases, in my attempt to gather up the radiance of a dynamic personality, I have been authorized to indulge in some judicious speculation and have occasionally asserted poetic truths where actual facts were missing." (emphasis added)

I had to read that twice. It took a while for the realization to solidify that the author was saying, "When I didn't have solid evidence to tell the subject's story, I just made stuff up." Really? At this point I went directly to the back of the volume where I found no list of sources and no end notes...just a somewhat sparse index. The conclusion became obvious: nothing in this book can be trusted. Any assertion made by the author is just as likely to be a "poetic truth" as an "actual fact".

Lawrence Burst Sperry deserved better than this.

Some examples illustrate the scope of the problem. The book tells a tale (one can't say "the tale") of the development of the gyro-stabilizer (precursor of the autopilot) for use in aircraft. It would have you believe that Lawrence, with minimal involvement of his father, the noted engineer Elmer A. Sperry, designed, developed and demonstrated the apparatus completely on his own. His native genius is depicted as a perfect substitute for the engineering education he regarded as unnecessary. But other sources cast doubt on this charming narrative.

A biographical memoir on Elmer A. Sperry by J.C. Hunsaker (published in 1954 by the National Academy of Sciences) has this to say:

"As (Elmer) Sperry was tied up with...other activities, he called in his friend Hannibal C. Ford, an extremely clever designer of intricate apparatus. Ford and Sperry together started on the design of a gyro compass... As a sideline they designed a small gyro stabilizer for an airplane..."
This was in 1910. Hunsaker goes on to say:
"In 1913 conditions seemed ripe for resuming the airplane
stabilizer work started but discontinued in 1910. Sperry knew Glenn Curtiss at the Aero Club in New York, got in touch
with him, and arranged to send his son Lawrence to Curtiss's shop at Hammondsport. Lawrence Sperry had already built
and flown his own airplane and later was awarded F.A.I. Pilot's License No. 11.

The Aero Club of France announced an international competition for a safe airplane with a prize of 50,000 francs to be awarded to the winner. Curtiss, in whose flying boat the gyro stabilizer had been tested, persuaded Sperry to send Lawrence to Paris to compete for the prize. The demonstration flight was made in June 1914.

As the plane flew low past the judges' stand the mechanic climbed out on the wing and Lawrence stood up in the open
cockpit raising both hands above his head. This was indeed convincing; nothing like it had ever been seen before. He won the prize."

The patent application for the airplane stabilizer was filed on 17 July 1914 and led to the issuance of US patent 1,368,226. The sole inventor named on the patent is Elmer A. Sperry. In addition, the work to develop the airplane stabilizer was honored with the award of the prestigious Collier Trophy for 1914. One name is engraved on the trophy for that year – that of Elmer A. Sperry.

Was Lawrence involved in, and important to, the project? Most certainly. Was he the driving force behind it? It would seem not.

Another example revolves around the origins of the aircraft type most often associated with Lawrence Sperry – and the one that eventually took his life. Known most commonly as the Sperry Messenger, it got its start in life, according to the author, when:

"Billy Mitchell...wanted an inexpensive, maneuverable little single-seat plane that the Army could use as a training ship for pursuit aviation. This coincided precisely with Lawrence's desire for a single-seater sports plane. He went to his drawing board and designed a small biplane whose lower wing was almost unnoticeable. Delighted with the design, Billy Mitchell ordered three of the planes, the first sports plane in American aviation, for the War Department. This plane was the famous Sperry Messenger; it was Billy Mitchell who gave it it's name." (Emphasis added.)
But other sources tell a different tale. For example, K.O. Eckland's authoritative Aerofiles site says:
"M-1 Messenger, M-1A, MAT (Verville-Sperry) 1920 = Army liaison and utility. Designed at McCook Field by Alfred Verville; aka Engineering Division M-1. Ailerons on all wings. POP: 22 as military M-1 and 20 as M-1A, plus 1 civil sport version that failed to spark any public interest, and the idea was never pursued."
Did Lawrence Sperry go "to his drawing board" and give birth to the Messenger? He absolutely did not. The talented Alfred Verville, working for the Army, designed the airplane and the Lawrence B. Sperry Airplane Co. was then hired to build it. (The Smithsonian, by the way, agrees.)

There are other statements at variance with accepted facts throughout the book. The text includes many instances of direct quotes from conversations where only two people were present and no record could have been made. More of those "poetic truths", I suppose.

The question I'm left with is, "Why?" To what end does the author steal the glory of Elmer Sperry, Alfred Verville and others and assign it to Lawrence Sperry? He had plenty of his own glory as the legitimate inventor of the life-saving gyroscopic turn-and-bank indicator (see US 1,433,102), as developer of major improvements in pack parachutes for pilots, as a central part of the project that developed the first "cruise missile", as a renowned aviator and proselytizer for flying in its early days. And yes, even as the spiritual founder of the Mile High Club (with essential assistance from Mrs. Waldo Polk). Why would the author risk his credibility, with all of this to work with?

Perhaps the clue lies in the use (seen above, in the quoted segment about "speculation" and "poetic truths") of the word authorized. I'd suggest that the author was not free to write his own book. Someone else had to be considered and satisfied. The story that was told had to be, at the end of the day, the authorized version. What a shame.

If you want to learn about Lawrence B. Sperry, go ahead and read this book. Then verify anything of particular interest through other credible sources. That's the only way you'll sieve out the "actual facts" and leave behind the "poetic truths."

Monday, May 27, 2013

5,000 Flags of Remembrance

The Alexandria National Cemetery is just a couple of blocks west of my home in Virginia. This morning it was, as it usually is, peaceful and serene. There are about 5,000 gravesites there; it has long been filled to capacity. But while the rituals of commemoration have shifted to Arlington, remembrance continues. This morning's sun rose on 5,000 flags, one placed at each marker to say to those that rest here (and to those that love them), "We WILL NOT forget!'


As always on Memorial Day, my thoughts turn to my uncle, Tec 4 Edmund J. Peters, Jr., 188th Glider Infantry Regiment, 11th Airborne Division, who fell on 17 February 1945 in the assault on Fort McKinley and rests at the American Military Cemetery in Manila. May he rest in peace.

Tuesday, April 30, 2013

2013 Annual Inspection (ii)

This year's Annual Inspection, now completed, was an unusual one. And I mean that in a good way. There was very little "emergent" work resulting from the inspection and most of the work effort was focused on items properly classifiable as "maintenance". Even the one major cost item, the inspection and resealing of the propeller (first discussed here) was not the result of a "squawk". The prop was turning just fine when removed from the airframe.

If you wonder what happens when the propeller shop is told to "IRAN & Reseal" rather than overhaul, the log entry for the propeller work is instructive:

"Propeller disassembled, cleaned and visually inspected for red dye oil leak. Replaced all seals and gaskets. Reassembled, set angles, track and balanced. Propeller filled with red dyed oil and pressure tested."

The engine, at 1749.3 hours Since Major Overhaul (SMOH), seems to be holding up very nicely. The pressure drop data is perfectly acceptable (see the chart at left for seven years of data), the filter media were free of metal particles and there were no worrisome indications found by borescope. An oil sample has been sent off for spectrometric analysis but I don't anticipate any bad news from that quarter.

I flew the airplane for a 1/2 hour local test flight last Thursday evening with the only squawk being that the landing lights (both of which were replaced) were inop. As it happens, there is an in-line connector in the wire harness that supplies power to the landing lights and it has to be unmade to remove the lower cowling. In this case, it didn't get re-made when the cowl was re-installed. That minor glitch was remedied the next day and on Friday I flew N631S down to the DC area for the first time in three weeks. Then we flew back, mostly in rain and clouds, yesterday morning. No new problems showed up so I'm ready to call it done.

The only leftover item – which is an expected issue – is the need to adjust the Shadin Miniflo-L fuel computer to correctly interpret the output of the replaced fuel flow transducer. Every transducer is tested by the manufacturer to determine the number of electrical impulses it emits per gallon of flow passing through and that "K-factor" is supplied with the sensor. For this unit, the K-factor is 19.8, meaning 19,800 pulses per gallon. Right now, the computer is reading about 10% high. To correct the condition it has to be removed from the panel and reprogrammed with the new K-factor. Naturally, this can't be accomplished in situ, as that would be far too easy. So sometime soon my friends at Three Wing Aviation Group (check out their spiffy new web site!) will make the adjustment and all will be well.

I anticipate one more post about this year's Annual wherein I'll analyze the final invoice.

Wednesday, April 10, 2013

Eternal Father, Strong to Save...

On 10 April 1963, fifty years ago today at 9:18AM EST, the Sea enveloped in her cold embrace the 129 men aboard the USS Thresher and took them away from their loved ones forever. It is important that we remember.

I remember. I was 14 at the time and in the habit of listening to Jean Shepard's program on WOR radio from New York before going off to sleep. There was a news bulletin. The Navy was reporting one of its submarines as overdue at Portsmouth Navy Yard. A search was underway. I had no understanding of abyssal deeps and vast pressures, and so I went to sleep with hope. As I'd understand in future years, my hope was unjustified.

Of course, a day or so later, the finality of the loss was made clear. She was gone and her people were gone. The convening of Boards of Inquiry was announced. It was the first loss of a nuclear powered submarine, and in fact the lead ship of a new class, so naturally much was made of the disaster. But little information was forthcoming and of course the events of November of that year drove everything else from the front pages.

I really didn't think very much about Thresher until eight years later, in the summer of 1971 when I went to work as a design engineer at the Electric Boat Division of General Dynamics Corporation. Immediately, I was plunged into the design effort to incorporate modifications known collectively as SUBSAFE on the forthcoming second overhaul of the Lafayette class of ballistic missile submarines. The work embodied in the SUBSAFE program was the direct result of the loss of Thresher.

There are two aspects to SUBSAFE. One is an intensive quality assurance regime encompassing both materials traceability and rigid process controls. The other involves improvements in systems design to ensure that the casualties that are inferred to have led to the loss of Thresher can never again have similar consequences.

Based on the painfully limited evidence, those investigating the ship's loss concluded that the precipitating casualty was the failure of a seawater pipe joint in one of the ship's machinery spaces. The crew was unable to secure the inflow of seawater from this failure. The intense spray, driven by the pressure of the sea at or near Thresher's design depth, would have penetrated electrical control panels and caused the loss of propulsion. (NB: Recently a countervailing theory has emerged which posits that the seawater piping failure is neither likely nor necessary to account for the loss of the ship. The sinking, it holds, could have followed from loss of propulsion due to an electrical casualty compounded by a failure of the ballast tank blow system.)

At the time, the design and operation of the nuclear propulsion plant was governed by a philosophy that focused on saving the reactor at any cost. So any disruption of control circuitry would cause an immediate reactor plant shutdown. But this deprived the ship of the ability to use hydrodynamic forces against the effects of the flooding casualty. Would a few more minutes of propulsion have made a difference? We'll never know.

The last hope would have been use of the ship's high pressure air banks to blow the main ballast tanks on an emergency basis. Testing later showed that the rapid flow of air through the system would have caused plummeting temperatures and formation of ice that would block the piping and prevent the air from reaching the tanks. With no way to deballast, no propulsion, and no way to secure the flooding, Thresher was doomed.

With the adoption of this scenario as "probable cause", the SUBSAFE program set out to address each stage of the cascade of casualties. The quality assurance aspects sought to ensure that all seawater piping systems could always withstand the pressures of the deep. But if that failed, hydraulic remote valve actuation systems were installed (that was the piece of the puzzle I worked on) to ensure that hull and backup seawater valves could be shut to secure flooding. And last, the Emergency Main Ballast Tank Blow system was completely redesigned to ensure that it would be effective under all circumstances.

Outside of the bounds of SUBSAFE, the design and operating philosophies of the Naval Nuclear Propulsion Program were modified to allow ships to maintain propulsion as long as possible in the event of a casualty even if damage to the reactor is a possibility.

Did SUBSAFE accomplish its mission? The evidence says that it did. From 1915 until the loss of the Thresher sixteen US Navy submarines were lost to non-combat causes. Afterward, the only such loss was that of Scorpion in 1968. That ship was not yet SUBSAFE certified.

I am proud to have been involved in a modest way in the implementation of SUBSAFE. And I hope that the surviving relatives and friends of those lost aboard Thresher 50 years ago can find solace in the fact that their loss led directly to a profound reduction in the risk of submarine operations.


Eternal Father, Strong to save,
Whose arm hath bound the restless wave,
Who bid'st the mighty Ocean deep
Its own appointed limits keep;
O hear us when we cry to thee,
for those in peril on the sea.

Tuesday, April 2, 2013

2013 Annual Inspection (i)

Yesterday was the first day of N631S's Annual Inspection availability for 2013. My friends at Three Wing Aviation Group will be doing the inspection and associated work package and this year Tony diNuzzo is the IA on the case. I've known and respected Tony for a long time now, and am looking forward to working with him.
Our last flight up from the DC area had been uneventful and I had very few "squawks" to report. The taxi light bulb had burned out a couple of months ago, and the landing light joined it about a month back, so both of those bulbs will require replacement. And the performance of the Shadin Miniflo-L fuel totalizer has been increasingly erratic, so we'll take this opportunity to replace its transducer with a spare that I acquired a year or so ago.

Beyond those tasks, the most notable work-item planned for this year is an inspection of the McCauley constant speed propeller. The prop was overhauled in conjunction with the 2005 Annual Inspection – the first year N631S spent with us – and so it now has about 1,200 hours and eight years SPOH. McCauley holds that the recommended TBO (Time Between Overhauls) is 2,000 hours or seven years, whichever first elapses.

I feel no compulsion to overhaul components at some arbitrarily selected calendar time or time-in-service, as I'm a firm believer in maintenance "on condition". N631S's Continental O-470U engine has a recommended TBO of 2,000 hours or 12 years. The latter mark has long passed and I will cheerfully let the former pass unremarked as well, so long as the engine is talking to me and saying, "I'm fine, boss...let's go fly." And it will do so through spectroscopic analyses of the oil, visual inspections of the filter media and borescope inspections of the cylinders and valves. Ah, but the propeller presents a different problem.

The propeller is a "black box". It doesn't speak to you and there is no way to know that it is sick until something Very Bad happens. Recently, blogger Ron Rapp did a post (which I endorse in its entirety) on Constant Speed Propeller Maintenance, where he describes some of the Very Bad Things that can happen to a sick propeller with terrifying suddenness. I take these things to heart and view propeller maintenance as something you neglect at your mortal peril.

That said, I don't want to "overhaul" the propeller. In the world of aviation, the word "overhaul" has a very specific (and expensive) meaning. It means that you drag out the manufacturer's overhaul manual and do everything that it says to do. But N631S's prop was overhauled back in 2005 and since then has accumulated about 60% of the hours McCauley assigns for TBO. It's just nicely broken in, from the perspective of hours in service, and I'd argue that an overhaul would be premature. My concern is directed more toward the notion that non-metallic parts wear and rubbery things deteriorate more in step with the calendar than with the Hobbs meter. So I've asked Three Wing to take the prop off and send it to New England Propeller (who did the overhaul in '05) with instructions to "IRAN and Reseal". That means, "Inspect and Repair As Needed (to serviceable condition) and renew all fluid seals". Once that is done, I'll happily run the prop for another 1,000 hours before sending it off for "Overhaul".

I stopped at Three Wing this morning and spoke with Tony. He'd done the maintenance run-up and found nothing noteworthy. The cylinder leakdown test had gone satisfactorily. Cylinder #2 was a bit weak at 59 psi (on a day where the minimum acceptable result was 46 psi). Tony will continue and I'll be visiting N631S every day for a while.

Friday, March 29, 2013

"Contact the Tower..."

The Air Traffic Control Tower (ATCT) at my more northerly "home 'drome", Sikorsky Memorial Airport (KBDR), is scheduled to close on or about the 5th of May due to the funding cut-off known as "sequestration". The closure seems to be for an indeterminate period. After Cinco de Mayo, KBDR will become a non-towered field.

The tower at KBDR is one of well over 100 "contract towers" that the FAA is standing down to save money. Arguably, some towers that are to be closed are in fact busier than some FAA-staffed towers that will remain open. But the plug can be pulled on the contractor operations with far less bureaucratic fallout than would ensue if the jobs of Federal employees were affected. The half-dozen or so controllers at KBDR, employees of Midwest Air Traffic Control Service, Inc. who I hold in high regard, will be out of work.

It has been quite interesting to attend to the comments from various parts of the aviation community as the tower closures went from rumored to probable to inevitable. Many voices have been raised (some informed, some less so) to decry a predicted reduction in "safety" with the closing of these facilities. But a substantial part of the community is adopting a "Keep Calm and Carry On" attitude. In truth, pilots have always known how to operate around non-towered fields without undue risk and I am quite confident that operations will continue without a sudden epidemic of bent aluminum.

There are, however, two issues raised by the sequestration-related tower closures that have not been widely discussed. One is short term and operational in nature, the other is long term and can change the nature of the system in which we fly.

The tower at an airport like Sikorsky Memorial has two main functions that affect me in my comings and goings. The first and most important is to "control" local traffic, both on the ground and airborne, so as to maintain safe, orderly and expeditious use of the available runways. Traffic at a fairly low-volume field like KBDR, operating under non-towered field procedures, will no doubt become somewhat less expeditious, slightly less orderly, and (I contend) just about as safe. Pilots arriving and departing VFR (i.e., under Visual Flight Rules) should hardly notice the difference. But there may be a significant impact on pilots operating IFR (under Instrument Flight Rules) as N631S and I usually do, absent the tower's other normal function.

The control tower provides a link between the departing or arriving IFR pilot and Approach Control. The tower controller delivers your IFR clearance, obtains your release and sends you on your way. On arrival, it's the tower that cancels your IFR flight plan. Now, IFR pilots will need to interface directly with the TRACON to accomplish these things.

There is no reason that any of this needs to be a big deal. I do it routinely, interacting with Potomac Consolidated TRACON when departing or arriving at KVKX in the DC area. But – the TRACON's are going to be having some sequestration effects of their own. It's reported that controllers will be getting an unpaid day off per payroll period and that translates into fewer controllers on station and higher workloads for the ones on duty. So I expect that departing KBDR on a busy Friday afternoon in the summer when convective weather is rumbling around the area could become difficult. Problems picking up clearances and long waits for release may become the norm. I hope that a few weeks will suffice for development of "work-arounds" and for all the players to adapt.

The second issue that needs some discussion concerns the length of the tower shutdown. There is, I believe, a very significant probability that for many of the closing towers – and I think KBDR is one – the closure may be permanent. Here's the problem:

The chart above (you can click on it to make it readable) depicts annual airport operations at KBDR from 1994 (the year I got my Private Pilot's license) through 2012 with a trend line extending out another five years. The data is from the FAA's Air Traffic Activity System. In 1995 the field had 114,247 operations. Last year it had 61,911, a decline of 45.8%, and the trend line suggests a further drop to about 45,000 by 2017. There is some variability in the data but the long term trend is unmistakable...traffic at KBDR is going away.

I remember a sunny Sunday afternoon in 1995, when I was flying a Cessna 172N (N6583D, I believe) rented from the old Bridgeport Air Center. I'd departed KBDR, flown around for a while just enjoying the delightful day, done a couple of touch & go's at Oxford, then returned to Bridgeport. Arriving there, I found myself one of eight airplanes in the traffic pattern, a number of them students in closed traffic exhibiting shaky pattern discipline (not that I was so great at that point). The tower controller was holding on by his fingernails – but he was hanging on. Making right traffic for Runway 29, I was asked for a left 270 for spacing. An airplane arriving after me was told, "Remain clear of the Class Delta". I soon got my turn at the runway and was grateful for it.

That's the kind of day when you need a tower. Those kinds of days don't happen any more. In 1994 there were three active flight schools at KBDR. Today there is one (plus a few independent instructors). I really don't recall the last time there were more than two airplanes in the pattern while I was flying. The bottom line is that even after the budgetary kerfuffle that led to sequestration is over, it may be very difficult to justify re-opening the tower at KBDR given current traffic levels. And many more of the towers being closed this spring are likely to be in a similar situation. As a result, the once ubiquitous Class D tower may become a rarity.

After my next arrival at KBDR, N631S is going in for this year's Annual Inspection, which will take a couple of weeks. So it's quite possible that the next time I hear New York TRACON say, "Bridgeport is at your 12 o'clock, seven miles. Radar service terminated, contact Bridgeport tower on 120.9"...it will be the last time.

Saturday, February 23, 2013

Book Review: "The Dog Stars" by Peter Heller

The post-apocalyptic novel has been with us at least since Mary Shelley published The Last Man in 1826. The basic model is familiar – the author invokes some catastrophe to kill off the vast majority of humanity and then follows the lone (or few) protagonist(s) through the effort to survive and build a new future in a hostile world.

The nature of the precipitating catastrophe is rather beside the point. Writers have called upon plague, astronomical disaster, alien invasion and thermonuclear holocaust (recently, zombies have been popular). The point is what happens afterward.

For most of the latter half of the last century, nuclear war was the preferred disaster (see Nevil Shute's On the Beach, Pat Frank's Alas, Babylon, and Walter M. Miller, Jr.'s A Canticle for Leibowitz). Of late, however, the pendulum seems to have swung back to favor pestilence. Which brings us to Peter Heller's recent work, The Dog Stars.

Fine, you say, ...but what has this got to do with aviation? Well, the connection involves one of the important supporting characters in the story. In this tale, a virulent strain of influenza has carried off almost all of the population. The protagonist, a survivor who goes by the name Hig, lives at an airfield. He has a friend, and a dog, and an airplane. That would be the Beast.

"I hand pump the 100 low lead aviation gas out of the old airport tank when the sun is not shining and I have the truck too that was making the fuel delivery. More fuel than the Beast can burn in my lifetime if I keep my sorties local, which I plan to, I have to. She's a small plane, a 1956 Cessna 182, really a beaut. Cream and blue. I'm figuring I'm dead before the Beast gives up the final ghost."

The friend is the aptly named Bangley, who is testy and a bit of an odd duck, but who has the redeeming virtue of being a crack shot and well equipped with automatic weapons and things that go boom. Hig and the Beast patrol their perimeter from the air and Bangley sees to security. Hig's other job is to go up to the hills with his dog Jasper and bring back the occasional deer or some carp (the trout being gone since the streams warmed up).

Hig's life is pretty stable, but his focus is on the things that are gone. The things of Before. He holds on tenaciously to the connections with Before.

But of course, the connections break and Hig comes adrift. He has to go off in search of new moorings. It's the Beast that enables him to do this, taking him to unexpected places where unforeseeable events turn him away from the past and toward the future. And when he has to get himself (and newly met others) out of a tight spot he achieves his goal using his own skill and the Beast's reliability and horsepower. (Incidentally, this occurs in one of the best accounts of a back-country short field takeoff that you'd ever care to read. I couldn't breathe 'til they cleared the trees!)

At the end of the tale, Hig still has a precarious existence, albeit with a couple more people to be close to. But he's shed his longing for the past and found reasons to hope for a better future. And he's still flying.

The Dog Stars would be a fine read even without the airplane. Peter Heller writes vividly and packs a great deal of meaning into few words. The reader comes to know Hig quite well and to care what happens to him. And for a pilot, the aviation related scenes are icing on the cake. The author presents them using correct terminology but never lapsing into jargon that might put off the groundling reader. And very few errors crept in during the editing process (though I did wince when an oil change involved a case of "50 straight weight Arrowshell").

We learn that the Beast wears registration N6333A which, by coincidence, is also the N-number of a '56 Skylane owned by Peter C. Heller of Denver, CO. So Hig comes by his love of flight legitimately. I recommend Mr. Heller's book to you, and I hope he and '33 Alpha enjoy many years of flying together.

Thursday, February 21, 2013

My '709 Drive

Those of you that visit here regularly will recall that early in January I was involved in an incident wherein N631S struck and slightly damaged another aircraft (described in this post). At the time I had a cordial conversation with Dean, the assigned FAA Inspector who was opening a file on the incident.

A couple of weeks later, I received a letter from the FAA, sent via Certified Mail, inviting me to participate in a re-examination of my qualifications to hold a pilot's certificate. The re-examination would focus (logically enough) on taxiing and ground operations. I had 10 days to get back to them to schedule the event.

This sort of re-examination is conducted under authority granted to the Administrator by 49 USC 44709(a), which says:
Reinspection and Reexamination — The Administrator of the Federal Aviation Administration may reinspect at any time a civil aircraft, aircraft engine, propeller, appliance, design organization, production certificate holder, air navigation facility, or air agency, or reexamine an airman holding a certificate issued under section 44703 of this title.

The re-examination is usually referred to as "a '709 ride" (from the referenced USC section). In my case, since we would only be dealing with ground operations, it would be more like a '709 drive.

I called Dean at his office at the Windsor Locks Flight Standards District Office (FSDO), located at Bradley International Airport (KBDL). After a couple of false starts related to our conflicting schedules we agreed that N631S and I would meet him today at the Hartford-Brainard airport (KHFD). We'd talk for a while, then I'd taxi around a bit while he watched. He'd be evaluating my competence based on the relevant sections of the Practical Test Standard for Private Pilots.

The morning dawned clear but quite breezy. I took a look at the winds at Brainard and was less than thrilled with what I saw:
 
KHFD 211353Z 29013G23KT 10SM CLR M02/M13 A2992 RMK AO2 SLP131 T10221128
The runway at KHFD is oriented 2 - 20, so a wind from 290 is a direct crosswind. At 13 knots gusting to 23 it was fairly sporty already and I suspected that it could easily get more intense as the day went on. I sent Dean an e-mail saying I looked forward to meeting him and commenting on the winds. Very shortly, he called me and asked if I'd like to meet instead at Bradley (KBDL). Bradley has a Runway 33 that would make the wind perfectly manageable so I accepted immediately.

N631S and I departed Sikorsky Memorial (KBDR) at about noon and had a bumpy forty minute flight up to KBDL. Bradley Approach sequenced us into Runway 33 behind a Delta MD-80. The wind was 31020G26KT, and did not present any problem.

I parked on the ramp at the FSDO and announced myself. Dean came down to collect me and escorted me to a conference room. We sat and talked about my incident and about risk-management in ground operations (a subject to which I have given considerable thought of late). He focused strongly on avoidance of runway incursions – still clearly an FAA 'hot button'. While this was going on, one of Dean's colleagues went out and ramp-checked N631S. He joined us and said the only question he had concerned the cable connecting the portable Garmin gps396 with the panel-mounted GNS-530W. It supplies both 5.0v power and flight-plan data to the portable and he wants to see the log entry supporting the installation. Of course, the airplane's logs are home in Virginia so I am on the hook to dig out the pertinent page and send it to Dean.

After about 45 minutes, Dean said, "OK, let's go out and taxi around."

We went out to N631S, started the engine, and taxied over to the Tac-Air FBO ramp. There, we went through the motions of parking. Dean indicated a few spots and said "Would you park there?" or "Could you pull straight in to that spot", or "How could we best get to that spot over there?". I said 'Yes' or 'No' or 'NO WAY!' in what seem to have been all the right places and after about 15 minutes we taxied back to the FSDO ramp. Dean said he'd send me a letter next week attesting to my competence and continued qualification to hold a Private Pilot's Certificate and I was free to go. N631S and I had a somewhat bumpy but really quick flight back to Bridgeport and it was done.

I can't say it was a pleasure, but the experience was minimally painful. Dean, the FAA Inspector, was cordial and totally professional at every turn. I know all of the jokes about the FAA but none of them applied here. I drew one of the "good guys".

Wednesday, February 6, 2013

Book Review: "A Higher Call" by Adam Makos

Charlie Brown was perfectly clear about the situation. When the young journalist, having "heard a story", sought him out for an interview, he said, "If you really want to learn the whole story, learn about Franz Stigler first...in this story, I'm just a character – Franz Stigler is the real hero."

Author Adam Makos had no choice but to seek out Franz Stigler, living in pleasant retirement in the Vancouver area, to learn what happened on 20 December 1943, in the skies near Bremen. There, the life arcs of two warrior-aviators intersected for about 10 minutes. If someone had described to their earlier selves what transpired during that brief encounter, they would each have reacted with disbelief. But as they moved on along separate paths – destined to intersect again nearly 50 years later – they knew their lives had changed forever.

On that morning over Germany, Charlie Brown was the 21 year-old pilot of a terribly damaged B-17. He was embarked on a first combat mission that had become deadly and terrifying. Franz Stigler was, at 28 years of age, an elite Luftwaffe veteran of hundreds of missions in the Bf 109. He was fighting to defend his homeland and his countrymen from the onslaught of the American bombers. Both of them had already on that day displayed heroism in battle. But when they met, there was nothing left for Charlie to do. Keeping his crew alive and his airplane aloft to that point had exhausted his resources. He could only watch and wait.

As he approached the straggling bomber, it fell to Franz Stigler to make a choice. The action required by the call of duty was clear. He should attack and destroy the wounded B-17. But perhaps there was a higher call, requiring forbearance. Perhaps honor and humanity required staying the hand of destruction. It was time to decide. Act, in answer to the call of duty...or act not, in answer to the higher call. The sum of all his experiences led to the choice that few would have predicted and few would understand. "This will be no victory for me, Franz decided. I will not have this on my conscience for the rest of my life."

How did an elite warrior, the product of a proud martial tradition, come to make this choice? This is perhaps the most fascinating question raised by the episode and the author sets out to answer it. This requires a thorough study of Franz Stigler's life, and Makos provides it. We learn where Franz came from, how his love affair with the sky originated, how his sense of honor evolved.

We're taken back to Bavaria in the late 1920's where young Franz begins to fly, under the auspices of a local glider club sponsored by his father, the elder Franz (who had been a scout pilot in the Great War) and Father Josef, a local Catholic priest who had been a fighter pilot in that war. Following in the footsteps of his elder brother August, Franz flew a simple Zögling ("Pupil") glider that was launched using a bungee cord, from the side of a hill. It was said that, "[b]ecause training was conducted solely by solo flight the aircraft had to be very easy to fly and also easy to repair." This principal was demonstrated by young Franz, who pranged the club's glider on his first flight, but soon became proficient.

Franz was urged by his devoutly Catholic mother to enter the Seminary, but Father Josef, the fighter pilot, glider club sponsor and family friend, urged him to follow his dream of flying. He took advantage of government training programs and found himself, in the late 1930's, flying Ju 52's for Lufthansa. In due course, he was transferred to the newly emerging Luftwaffe and set to work as an instructor. One of the students he found himself responsible for was his elder brother August.

While Franz continued to instruct, August went on to serve as a night fighter-bomber pilot flying Ju 88's from France against England. It was late in 1940 that Franz learned that August had been killed in an accident at night, on takeoff. The loss of his brother moved Franz to seek a transfer to fighters. There followed 18 months of preparation and training, until in the spring of 1942 Franz Stigler arrived in North Africa to serve as a fighter pilot in Jagdgeschwader 27 (JG 27).

JG 27 was a famous unit, the home of the great ace, Hans-Joachim Marseille. Franz was in good company. He was assigned to the squadron of Leutnant Gustav Rödel. His new commander quickly gave him a lesson that would have a profound influence on him:

"Every single time you go up, you'll be outnumbered. Those odds may make a man want to fight dirty to survive. But let what I'm about to say to you act as a warning. Honor is everything here. What will you do, Stigler, for instance, if you find your enemy floating in a parachute?"

"I guess I've never thought that far ahead yet," Franz said.

"If I ever see or hear of you shooting at a man in a parachute," Rödel said, "I will shoot you down myself. You follow the rules of war for you, not for your enemy. You fight by the rules to keep your humanity."

As the author recounts in some detail, Franz flew and fought under Rödel's leadership in Africa for five months. His unit was then transferred to Sicily, where he continued to fly and fight for another ten months. During this period he met Adolf "Dolfo" Galland, the famous General of the Fighters. He managed to impress Galland with his views on tactics for effective attacks on heavy bombers. This relationship would be important to Franz' future more than once in the coming years.

In mid-1943 the strategic bombing campaigns of the Allied Air Forces were beginning to have real effects on the German homeland. Fighter units, including JG 27, were transferred back to Germany to engage in homeland defense. The stage was being set for an epic confrontation.

Meanwhile, Charlie Brown and his crew were readying themselves to join the fight. By the fall of 1943 they had joined the 379th Bomb Group of the mighty 8th Air Force at RAF Kimbolton. They'd been assigned a veteran B-17F named Ye Olde Pub.

On 20 December the 379th took off for a raid on Bremen. Ye Olde Pub, with a rookie crew, was assigned the trailing position, known as "Purple Heart Corner". The slot would soon once again earn its name.

On the approach to Bremen, before reaching the point where its load of bombs would be dropped, Ye Olde Pub was hit by flak. The Number 2 engine was knocked out, and the bomber's Plexiglas nose was shattered. Charlie pressed on. Another burst of flak damaged the Number 4 engine just before the bombardier released Ye Olde Pub's deadly load. As the group turned away from the target, Ye Olde Pub with one engine out, one producing partial power, and drag increased by the damage to the nose slowed and began to fall behind the formation. Soon, a group of eight Fw 190 fighters focused their undivided attention on Ye Olde Pub.

The author's chapter describing the fight between the B-17 and the Focke-Wulf's is intense and thrilling. It describes Charlie's desperate maneuvers, the crew's efforts to fight back, and the horrific damage inflicted by the fighters. In the end, the bomber rolled into an inverted spin when the pilots, their oxygen system disabled, blacked out. The Fw 190's – either out of ammunition or certain that their job was done – moved on.

About 10,000 feet above ground, Charlie awoke. He started to try to recover the airplane from its spin, and barely succeeded in regaining level flight below 2,000 feet.

The damage and casualty reports were frightening. The tail gunner, Sgt. Hugh 'Ecky' Eckenrode, was dead. Two other crew members were badly wounded. The airplane was riddled with holes and many systems were destroyed or compromised. They were staggering toward the coast, at low altitude, on 2½ engines.

Just then, Franz Stigler was on the ground at a nearby field while the ground crew rearmed and refueled his '109. He heard an approaching aircraft and looked up in amazement as a damaged B-17 flew westbound, almost directly over the field. Franz wasted no time in taking off to give chase.

Charlie struggled to get Ye Olde Pub to climb to 2,000 feet. He passed the word that anyone who wanted to bail out had his permission. No one took him up on it. And behind them, a Bf 109 piloted by one of the Luftwaffe's best pilots was closing in.

Franz closed on the B-17's tail, knowing that he needed to get close to be sure his attack would be effective. But when he closed in, he saw the damage to the bomber's tail section. He saw that the tail-gunner's weapons were disabled. He got close enough to to see the wind-driven streams of 'Ecky' Eckenrode's blood.

Franz slid his '109 to the right and moved forward along the right side of the B-17. Through a gaping hole in the fuselage he saw crew-members, not at their stations, but huddled together and caring for the wounded.

Franz decided then, that on this day he was not going to kill these men. He pulled even with the cockpit and slid over to the bomber's left side. He pointed to the north, repeatedly and mouthed "Sweden...Sweden", in an effort to get Charlie to turn toward the nearest haven. He was certain that if the B-17 tried to cross the North Sea and reach England it would crash and all aboard would be killed. Charlie Brown had no idea what he was saying.

Finally, over the sea, Franz gave up, saluted Charlie, and peeled away to return to Germany. Only then did he consider that if anyone had seen what he had done he'd certainly be court martialed.

Ye Olde Pub staggered across the North Sea at minimum altitude. The crew jettisoned everything they could to lighten the aircraft, but the B-17 was having difficulty maintaining altitude. Soon, their height above the sea was measured in hundreds, rather than thousands of feet.

As they approached the English coast a pair of P-47 Thunderbolt fighters joined them. They exchanged hand signals (the radios were out) and raced ahead. Charlie followed. As Ye Olde Pub crossed the English coastline, Charlie searched for a farmer's field to use as a landing site of last resort. Then he saw the two P-47's ahead, circling at 1,000 feet. He turned toward them and soon saw the runway they had found for him.

Minutes later, Charlie Brown settled Ye Olde Pub onto the runway at RAF Seething, home to the 448th Bomb Group. One of his crewmen was dead; two were injured severely enough that they would probably not have survived a bailout. The airplane would not go to war again.

The intelligence officers debriefed Charlie and he told them the whole story, including the odd behavior of the Bf 109 that had escorted them off the coast. The word came down to forget that had happened. Never mention it to anyone. It was unacceptable to say that a 'Nazi' had behaved with honor and chivalry.

Franz Stigler never experienced any repercussions from the incident with the B-17. He fought on with JG 27 through the first 10 months of 1944, in Germany and Jugoslavia. Then on 26 October 1944 a B-17 gunner's .50 cal. round, having spent nearly all of its energy passing through the canopy of Franz' Bf 109, struck him in the forehead. Amazingly, he lived. Not so amazingly, he suffered symptoms of brain trauma and was grounded by the flight surgeon. Franz was, for the time being, out of the war.

After a brief stay at a R & R facility, Franz pestered his group commander, still Gustav Rödel, for something useful to do, and Rödel was able to get him a slot at the jet school near the Messerschmitt factory in Augsburg. There he took to the Me 262 like a duck to water. He was kept on as an instructor, but ran afoul of a political officer and found himself released with no new assignment. That's when he remembered 'Dolfo' Galland.

The word was around. Galland had run badly afoul of Reichsmarschall Herman Goering and been sacked as General of the Fighters. But Goering had allowed him to form a new fighter group, Jagdverband 44 (JV 44), flying Me 262's. It was said that Goering couldn't arrest the famous and popular Galland but could, perhaps, arrange for him to die in combat. Franz called Galland and asked if he could join JV 44.

Galland told Franz that he'd be glad to have him as long as he brought a jet with him. So Franz went to the factory, stole a jet (details, quite entertainingly, in the book) and reported to Galland's group.

JV 44 may have been the most amazing unit in the history of air warfare. All of the pilots were considered experten. Nearly all were there because they had somehow run afoul of the Nazi political system. All of them were committed to defending the German homeland.

None of these men were found culpable for the crimes of the Nazi regime. Many of them would later serve with great distinction in the Air Force of the Federal Republic of Germany. But in 1945, they were still the enemy, fighting on for honor in a lost cause.

And of course, the war ended. Franz struggled to survive in the economic disaster that was post-war Germany. In 1953 he emigrated to Vancouver, Canada and became successful in business. Charlie Brown went to college, rejoined the Air Force and retired in 1965, then worked for the State Department before retiring for good in the early 1970's. But 20 December 1943 always stayed with him. At the urging of friends, he tried to place a query in a newsletter distributed to veteran Luftwaffe pilots. The editor turned him down, so he appealed to Dolfo Galland...who used his influence to ensure that the query was published.

In January 1990, in Vancouver, Franz Stigler collected his mail including the Jagerblatt newsletter. Minutes later, he was calling for his wife to come and see what he'd read. And he quickly wrote a letter.

Charlie Brown and Franz Stigler soon met and became the closest of friends. They referred to each other as 'brothers', and for many years they enjoyed a close relationship based on a bond that no one else could fully understand. Franz and Charlie both "went West" in 2008, six months apart. Franz' obituary said that he was survived by his brother, Charles Brown.

In this book, Adam Makos does a good job of describing the experiences that brought Franz and Charlie to their fateful encounter near Bremen. We're left with complete understanding of what happened. But I found myself wishing that the author had addressed "the elephant in the room". What are we to make of this story? Actions have consequences – what were the consequences of Franz Stigler's actions on that day in 1943? By choosing not to attack Charlie Brown's B-17, Franz made it possible for him to return to England with his crew. Charlie flew another 27 bombing missions with that crew (plus replacements) and dropped over 50 tons of bombs on German targets. Viewed in accordance with the cold calculus of war, it seems clear that Franz failed, on that day, to do his duty, and thus put his country in jeopardy. The author does not seriously address this issue.

The book's only allusion to the moral ambiguity surrounding Stigler's actions is in a mention of 'Dolfo' Galland's reaction. Stigler had kept in touch with Galland after the war, and he reported that the old General of the Fighters had mixed feelings about his story. He regarded Franz' actions on that day in '43 as a dereliction of duty – and also the right thing to do.

It's left to the reader to ask whether "the cold calculus of war" is decisive. What about the calculus of humanity? Remember what Gustav Rödel said to Franz Stigler: You fight by the rules to keep your humanity. When the war is over, do we want to welcome back into our midst warriors whose every choice was guided solely by the cold calculus of war? Or do we want to embrace warriors who have fought bravely and well, and yet have retained their humanity and can say that their honor is intact?

Today's wars are harder. The choices, never easy, are even tougher. But I know that I want men like Franz Stigler making those choices for our side.