Sunday, January 31, 2010

Snowed in, in Virginia

Actually, it's N631S that's snowed in; not me.

We drove over to KVKX to have a look at the status of snow removal operations (we had about 7 or 8 inches of snow yesterday). On the positive side of the ledger, the runway is clear, as is the taxiway and the fueling ramp.

The bad news is that the unpaved areas in front of the hangars and around the end of the hangar row leading down to the paved taxiway are still under about 5 inches of the white stuff. And it's going to get cold tonight. My evaluation is that there is no way I can expect with confidence to get the airplane out of the hangar tomorrow morning.

Tomorrow will be a fine day to fly. But I will be on the train and N631S will stay snug in the hangar for this week. And, of course, I'll be on AmTrak next Friday as well. 'Tis pity.

Changes at KBDR (cont'd (cont'd))

It was back in May of last year that I discussed here the demolition of the old KBDR passenger terminal to make way for Volo Aviation's new executive terminal and hangar complex. And in October I took note (in this post) that steel was being erected.

Now, the building is pretty much completed and, given its utilitarian role, I think that it looks OK (in this photo that I took Friday morning).

There is one minor issue. Take a look at this photo:

That white structure peeking out beyond the right corner of the hangar? Yep, that's the KBDR control tower. So? Well, now, if you depart the Three Wing FBO ramp, or if you taxi on the southwest end of Taxiway A, the tower says to you, "Not in sight." The tower controllers' view of those movement areas is blocked by the new hangar. I think that the tower can see (just barely) the approach end of Runway 6.

This is all, in my unschooled opinion, not an optimal situation. We'll just have to be careful out there.

Saturday, January 30, 2010

Optimism Justified

As it turned out, my optimism (discussed here and here) about making the flight from KBDR to KVKX was justified. Not that the trip was devoid of interest.

Here is the surface analysis for 21Z yesterday, a bit before my departure. You can see that the low up in the Canadian Maritimes is still the dominant feature. And those isobars were indeed wrapped pretty tightly, indicating a steep pressure gradient. Therefore, the winds did howl. In fact, when I took off KBDR was just inside the southern boundary of a rare (for these parts) SIGMET for severe turbulence below 6000 feet.

When the weather briefer told me about the SIGMET I asked if he had any PIREP's supporting it. Yes, he had three - which were collectively the proximate cause for issuing the SIGMET. One was from an aircraft in New Hampshire, one from north of Albany and one from a pilot in northwestern Connecticut (over the Litchfield hills). As these reports were all from "hill country", and my flight path would track just inside the southern boundary of the SIGMET area, I decided to proceed.

The METARs that bracketed my departure from KBDR had this to say:
KBDR 292152Z 30015G22KT 10SM CLR M07/M19 A3020 RMK AO2 PK WND 29026/2129 SLP227 T10671194
KBDR 292052Z 31018G24KT 10SM CLR M06/M19 A3018 RMK AO2 PK WND 29029/2021 SLP221 T10561194 53001

That peak wind report of 26 knots at 290, occurring at 2129Z, was just three minutes before my "wheels up" time (fortunately, from Runway 29).

There was some turbulence on the climb-out that you might have called moderate, but everything was smooth by the time N631S and I got up to 6000 feet MSL. Smooth but slow. The headwind component for my westerly course was 45 to 50 knots, so I saw a lot of ground speed readings in the 80's of knots. Over the Hudson the New York Approach controller cleared me up to 8,000 feet. By the end of that climb my indicated airspeed was down to about 75 knots (N631S's best rate-of-climb speed at sea level is 78 knots) and according to the flight log on FlightAware, this was happening:

Time Lat Long Course Knots mph Mach Alt Climb Rate
17:00 41.22 73.80 270° 36 41 0.06 8,000 +180

Yes, that's a roaring 36 knots over the ground. It was one of those days where you could easily drop back into slow flight and watch as the airplane went backwards at 10 or 15 knots.

Soon thereafter I had the following exchange with the New York Approach controller...
[N631S]: "New York, Skylane 31 Sierra, request."
[Approach]: "31 Sierra, go ahead."
[N631S]: "Any chance of Direct LANNA along here?"
[Approach]: "I hate to be the one to break this to you, but you're pretty slow today and I've got Newark arrivals backed up. It'll be a few minutes."
[N631S]: (sounding contrite) "Sorry for that...it's pretty windy up here today."
[Approach]: (best "there, there, it's OK" voice) "That's all right, it's not your fault. I'll have LANNA for you in a couple of miles."
And he did.

At right, here's what the entire flight track looked like. I finally made it to Sparta at 2223Z (about 50 minutes to go about 60 nautical miles), got to FLOAT intersection (just about over Reading, PA) 42 minutes later, and landed at KVKX at 0008Z. Everything happened a lot more quickly after the course became more south than west.

The storm system that has been tracking across the lower tier of states the last couple of days is making itself felt here in Virginia this morning - it's snowing as I write and the forecast calls for about 3 inches of accumulation. But with a little luck this will be gone soon and by Monday morning conditions will be good for a return flight to KBDR. More on that, later.

Thursday, January 28, 2010

Optimism (cont'd)

The forecasting products continue to suggest a favorable environment for flying down to the DC area tomorrow evening. The map at left was issued about 19Z this afternoon, valid for 00Z tomorrow evening. It looks a lot like the one that was issued yesterday. The northern edge of the precipitation field looks to be somewhere around Richmond.

The Bridgeport Terminal Area Forecast (TAF) for time of departure is looking pretty good, with no precipitation and scattered clouds at 5,000 feet MSL. Since the TAF says "scattered", I expect the layer to be rather thin and so I will certainly be on top at my usual cruise altitude of 8,000 feet. Here's the TAF:

KBDR 282332Z 2900/2924 29020G31KT P6SM SCT019 BKN080 
     TEMPO 2900/2901 6SM -SHSN BKN035 
     FM290200 31017G27KT P6SM SCT045 
     FM290900 32014G22KT P6SM SCT050 
     FM291600 32020G31KT P6SM SCT050 
     FM292200 31018KT P6SM SCT050

The middle of the trip will be over eastern Pennsylvania; the Reading TAF looks great, calling for few clouds at 25,000 feet MSL after 22Z:

KRDG 282325Z 2900/2924 31020G33KT P6SM SCT070 
     FM290500 30015G24KT P6SM SCT050 
     FM292200 30011KT P6SM FEW250

And, the TAF for Washington National (KDCA) tells me to expect a broken ceiling at 15,000 feet MSL and light winds out of the northwest on arrival:

KDCA 282330Z 2900/2924 32012G21KT P6SM FEW250 
     FM290300 33011G18KT P6SM SKC 
     FM290800 32009G16KT P6SM SCT060 SCT200 
     FM291300 31008KT P6SM FEW050 BKN250 
     FM291600 32010G16KT P6SM SCT150 BKN250 
     FM292200 34006KT P6SM BKN150

If there's any unpleasant news, it's that the westerly winds aloft will be strong -- FlightPlan.com is telling me to expect 2 hours + 50 minutes enroute -- and tomorrow morning about 0700 local time, when I'm at the airport stowing the baggage, removing the cover and "pre-pre-flighting" N631S, it is going to be very, very cold.

Wednesday, January 27, 2010

Do I Dare Be Optimistic?

I mean, with respect to the weather for Friday evening. There has been a lot of AmTrak Weather of late. I last flew from KVKX up to KBDR on the morning of January 4th. It was severe clear and cold and the trip was amazingly uneventful. Since then, the better part of discretion has been to leave N631S parked and make the weekend commute by train.

I did get up for an hour on the evening of the 14th (with a friend acting as Safety Pilot) to get in a couple of approaches "under the hood" to maintain my IFR currency. We flew the ILS 36 at KOXC to a miss and hold, and then the RNAV 24 at KBDR. Again, an uneventful flight.

(As an aside, it has proven harder to maintain IFR currency in winter than it was in the summer. Summer weather can usually be worked around, and every few trips you wind up needing to fly an instrument approach at the end. In winter, the weather seems to be either amazingly good VFR (no approach) or not flyable (no approach). Hence the need to log approaches under simulated conditions.)

Well, here is the 60 hour forecast map for 00Z on Friday evening. It looks fairly promising although that trough extending into central Virginia bears watching.

The forecaster has the following to say about the period in the NWS Forecast Discussion:

The models are looking fairly promising. The NAM model is calling for high overcast ceilings and minimal probability of precipitation throughout the evening. The GFS is just a bit less favorable with the ceiling down to as low as 6,000 feet by 00Z (that's OK, as ATC usually runs me over KBWI at 6,000) and the precipitation probability up to 13% (still pretty low) for the six hour period from 18Z to 00Z. The models agree that it's going to be cold, with a light northwest wind at the surface.

All in all, I think I'm justified in harboring some optimism. Time will tell all.

Wednesday, January 20, 2010

A Night at the Helicopter Factory

Forty years have passed since the last time I was inside the Sikorsky Aircraft helicopter assembly plant in Stratford, Connecticut. That was for a job interview and I wound up declining their offer, to join up with their corporate colleagues at Pratt & Whitney in East Hartford...which is another tale. But last evening Sikorsky hosted this month's FAA Aviation Safety Program seminar and included a guided tour of their manufacturing areas. Unsurprisingly, it was a sellout.

The tour began with a walk through the machining center. Of course, photography was not permitted so I'll have to illustrate with some photos harvested from the web.

Sikorsky doesn't do a great deal of part manufacturing in Stratford; most of the bits come in from sub-contractors. But a number of critical items -- like gearbox housings, many gears, rotor heads, rotor cuffs, and some rotor blades -- remain in-house. The finished parts are truly beautiful objects -- jewelry for a giant.

We moved on to the main assembly area for military programs where about 20 UH-60M Blackhawks and SH-60/MH-60 Seahawks were in various stages of completion. The MH-60 differs from the SH-60 in that it's a hybrid with a UH-60 fuselage. You can spot them because they have the tailwheel at the aft end, while a "real" Seahawk has it under the mid-fuselage so that the tail can overhang the deck edge when parked.
The latter tailwheel location, we were told, imposes a significant weight penalty on the structure.

These aircraft have been Sikorsky's mainstay programs for many years. In 2009, the firm delivered about 140 "Hawk" variants. They have ongoing construction contracts, and programs are in development to upgrade earlier models to late-model configuration.

Out tour guide then negotiated our admittance to the hangar ("No foreign nationals here, right?") where a number of completed aircraft were being fussed over by mechanics. One "M" model Blackhawk was powered up so we could all admire the glass panel, new to this variant. These aircraft now incorporate fly-by-wire control technology. I asked our guide to characterize Sikorsky's philosophy about flight envelope protection (a subject I've touched upon recently in this post). He said that there were "rings" of control limits and that the "inner ring", essentially a mechanical control emulation, was accessible to the pilot by passing physical control detents. In short, it isn't an Airbus.
Our group moved on to the commercial programs' final assembly bay where work was underway on S-92's for commercial customers and MH-92's for the Canadian Maritime Helicopter program. The MH-92 is definitely a state-of-the-art bird, with full fly-by-wire control and active vibration damping (using phase cancellation technology). The program is behind schedule and has endured quite a bit of criticism north of the border, but it is producing an elegant aircraft.

The S-92 is Sikorsky's commercial workhorse. The program's high-time airframe now has about 7,000 hours and they are holding up very well. They thrive in roles such as offshore platform re-supply where they endure adverse conditions and fly many hours every day.

We moved on to the fixed-base simulator where we saw the result of a program to address the hazard of "brown-out" when landing in dusty environments. The system uses a combination of inputs from millimeter-band radar and radar altimetry to generate a synthetic vision display of exceptional fidelity. If needed, it offers autoland capability in zero/zero conditions. As we watched its operation from the sim's observation platform the sensation of motion was uncanny, even though we knew the platform was welded down.

Our next stop was very special. We got to visit Mr. Sikorsky's office, which is maintained by the company as it was when he went West in 1972. It is modest in size but the walls are crowded with amazing memorabilia of one of the great aviation careers. It's good that the company keeps the memory of the man whose name it bears as a prominent part of its culture.
And of course, off to one side is the thing that everyone makes sure to see -- Igor's legendary fedora.

We wound up our tour with a short video presentation describing the leading edge X2 Technology. This aircraft incorporates coaxial contra-rotating rigid rotors and a pusher propeller and it is expected to achieve a speed of 250 knots.

All of us were very grateful to the Sikorsky Aircraft employees who volunteered their time so that a group of local General Aviation pilots could see what they are up to on the banks of the Housatonic River. We were highly impressed!

Saturday, January 16, 2010

Book Reviews: "Highest Duty" by Capt. Chesley Sullenberger and "Fly By Wire" by William Langewiesche

Highest Duty, Capt.
Chesley Sullenberger
with Jeffrey Zaslow,
William Morrow, 2009
Yesterday was the anniversary of the brief flight of Cactus 1549, the USAir Airbus A320 that on 15 January 2009 departed New York LaGuardia Airport's Runway 4, encountered a flock of migrating Canada geese, and ditched in the Hudson River due to the consequent loss of both engines. As I had a five hour train ride in store I felt it would be a good time to read two accounts of that flight: Highest Duty, written by the Captain who flew the Airbus, Chesley Sullenberger ("Sully" to almost everyone), and Fly by Wire by William Langewiesche.

I wanted to read the two books together because a certain amount of media commotion had accompanied their publication a few months ago. I wanted to see whether the fuss was justified.

Immediately after it became clear that the crew of Cactus 1549 had pulled off a remarkable feat of airmanship and that, somewhat improbably, all 155 souls on board had survived, the main-stream media went into overdrive to crown Capt. Sullenberger as the Hero of the Day. To his lasting credit, he never postured nor claimed the hero's laurels and he has been consistently generous in praising the performance of the rest of his crew, controllers and first responders that were involved in the incident.

Fly by Wire,
William Langewiesche
Farrar, Straus
and Giroux, 2009

The problem was that while Capt. Sullenberger was being hailed far and wide as the sole savior of Cactus 1549 (his own protestations notwithstanding), Langewiesche's book was thought by many to cloud the issue if not actually to rain on the parade. Some claimed (and a few of them may even have actually read the book) that Langewiesche considered the A320's fly-by-wire flight control system to be more responsible for the successful outcome of the day than Sullenberger's airmanship. Howls of protest echoed in the land, fanned by media eager to lead with controversy.

"Sully" himself weighed in, fairly gently after his own fashion, saying in an interview with the NY Times' Christine Negroni, that Fly by Wire “greatly overstates how much it mattered” that the plane he landed in the river featured an automated cockpit. He added: “There are some situations where the automation will protect a pilot, but at the same time a highly automated airplane makes possible other types of errors, so it’s a mixed blessing...and greater knowledge is required to fly a highly automated aircraft.”

And so I sat down with both mens' books, to measure their success in retelling the story of Cactus 1549 and to decide for myself whether the contretemps was justified.

Captain Sullenberger's book is a charming memoir of a decent, steady life. It is well written without being beautifully written. His collaborator, Jeff Zaslow, seems to succeed in remaining unobtrusive...the voice that comes through is very credibly Sully's. He goes back to his north Texas roots and describes the life experiences that formed his values system and readied him to face the challenge of that cold day last January. The portrait is clear - there is nothing not to like about this man.

He addresses briefly the role of automation in the cockpit. In a chapter titled "Managing the Situation" he suggests:

Automation can lower the workload in some cases. But in other situations, using automation when it is not appropriate can increase one's workload. A pilot has to know how to use a level of automation that is appropriate.

He concludes, "...technology is no substitute for experience, skill and judgment."

Then, Captain Sullenberger gets, I think, to the real point and the crux of controversy if one indeed exists:

One thing that has always helped make the airline industry strong and safe is the concept that pilots call "captains's authority." What that means is we have a measure of autonomy - the ability to make an independent professional judgment within the framework of professional standards.

Given that quote, it is easy to see how the full-authority digital control system of the Airbus, with its limits that no pilot can override, may be distasteful to a skilled airman who grew up believing in "captain's authority".

Every few years, I take down from the shelf one of my copies of Stick and Rudder by Wolfgang Langewiesche, and read it again. During the early years of the Second World War, Wolfgang wrote articles for Leighton Collins' Air Facts. He and Collins were intensely interested in improving aviation safety. In particular they were horrified at the regularity with which pilots killed themselves in stall-spin accidents. To Langewiesche, one key to alleviating this ongoing disaster was to spread awareness of the vital role of angle of attack. That became the central theme of Stick and Rudder, published in 1944 and still saving lives today.

Wolfgang Langewiesche was a writer of uncommon skill and lucidity. His son, William Langewiesche, has evidently inherited the DNA that provides for those skills and has added his own remarkably graceful style. The man cannot craft an awkward sentence. Besides his skill with language, he is an aviator of much experience who has displayed a willingness to challenge difficult situations aloft and conventional wisdom on the ground. If anyone was about to get pinned with the label of Contrarian with respect to Cactus 1549 it would be Bill Langewiesche.

And yet...I've read the book. At no point is the author less than respectful and admiring of the airmanship exhibited by Sullenberger and his crew. Very early in the book Langewiesche says that Capt. Sullenberger:

...possessed an attribute that those who mocked him (over the "Hero" tag) had overlooked: he was capable of intense mental focus and exceptional self-control. Normally these traits do not matter much for airline pilots, because teamwork and cockpit routines serve well enough. But they had emerged in full force during the glide to the Hudson, during which Sullenberger had ruthlessly shed distractions, including his own fear of death. He had pared down his task to making the right decision about where to land, and had followed through with a high-stakes flying job. His performance was a work of extraordinary concentration, which the public misread as coolness under fire. Some soldiers will recognize the distinction.

The controversy probably originates some pages later when Langwiesche broadens the focus of the discussion to include the A320's fly-by-wire controls. He says this of Sullenberger's flying:

In retrospect what mattered most to his ultimate success was not what he did, but what he chose not to do, his shedding of distractions, the concentration that he brought to the crisis. It was an exceptional performance, easy enough to dream up in the abstract, but extremely difficult to execute in practice. His physical control of the airplane, however, is another matter, and though nearly flawless, less reflective of unusual skill.

This is the author's introduction to the notion that the Airbus control system offered advantages that reduced the need for remarkable stick-and-rudder skill...as an aviator, Sully had to be without peer but as an airplane driver, he only had to be "good enough." Of course, howls of indignation arose from this "denigration" of Sully's skills.

At this point in his narrative the author introduces us to Bernard Ziegler, a French test pilot and engineer and the primal force behind the development of the fully digital controls of the A320 and its family. Ziegler's objective was to build what Langewiesche describes as "an airplane that could not be stalled - not once, not ever - by any pilot at the controls." And so the airplane incorporates multiple levels of speed and angle-of-attack protection with no provision for pilot override.

Of course, any design strategy has strengths and weaknesses. In response to a comment that the A320 is "easy to fly", Ziegler expressed ambivalence:

Yes, but you know sometimes I wonder if that was not our mistake. Sometimes I wonder if we made an airplane that is too easy to fly. Because in a difficult airplane the crews may stay more alert.

This concept is known in the human factors community as Automation Induced Complacency. I've written about it recently, in this post.

Langewiesche explores in some depth accidents like the Colgan Bombardier Q400 in Buffalo where an Airbus-like control system would probably have prevented the errant Captain from killing all on board, and the Habsheim A320 airshow crash where the Captain creatively found a way to drive the airplane into the ground despite the very best efforts of the control system.

Oddly, both Sullenberger and Langewiesche use the same accident -- AA965, a Boeing 757 that collided with terrain in December 1995 near Cali, Columbia -- to support their disparate views of the value of cockpit automation. To Sully, the story is a cautionary tale regarding automation because it was the Captain's confusion over the operation of the Flight Management System that put the airplane into jeopardy. But Langewiesche looks at how the Airbus control system might well have been just the small bit more efficient in the final emergency climb that would have allowed the flight to clear the mountain peak that it struck, a mere 200 feet below the summit.

In the end, however, despite the length and thoroughness of the author's detour through the thicket of fly-by-wire design philosophy, he agrees that its influence on the outcome of Cactus 1549's flight was not decisive:

They could have done it in a Boeing, too. But it was helpful to their immediate cause that they were working with the product of Ziegler's mind, in which computers took care of the menial chores...

Energy management. He had come to Ziegler's limit: alpha max. Given the circumstances his timing was astonishing and almost perfect. Years in the future...he will have proof in the data from this flare that he was a pilot at the peak of human performance. The fly-by-wire system took it from there. It was a very brief affair. Because of the airplane's inertia, it was probably unnecessary. But for the last few seconds of the glide, with Sullenberger's stick fully back, the computers intervened and gently lowered the nose to keep the wings flying.

So there it is. For three minutes, on the afternoon of 15 January 2009, Chesley Sullenberger flew an airplane as well as anyone has ever flown...and probably as well as anyone ever will. And as he did so, a remarkable digital control system made his job just a bit less difficult. One more quote sums up the reason that there ought to be no controversy here:

Across a lifetime of flying, Sullenberger had developed an intimacy with these machines that is difficult to convey. He did not sit in airplanes so much as put them on. He flew them in a profoundly integrated way, as an expression of himself. He lived through them. He knew their souls.

Captain Sullenberger flew the Airbus A320 in the way it had to be flown to preserve the lives of 150 passengers and the rest of his crew. If he had been flying a Boeing 737-800 he would have flown that airplane in the way that it had to be flown. Enough said.

So if all of this discussion of the Airbus control system is interesting but essentially peripheral to the results of the day, why does William Langewiesche devote such a large part of his book to it? It may be because he is his father's son. Because he knows that not every airline pilot is a Chesley Sullenberger. Because he has seen too many accidents like the Colgan Q400 where an airplane, correctly designed, could have avoided the loss of life. Perhaps the public attention drawn by the odyssey of Cactus 1549 has provided a platform from which to stir up new ideas...or to reinvigorate old ideas.

I'm sure William Langewiesche has read Stick and Rudder more times than I have. He is certainly very familiar with these words published by his father, Wolfgang, 65 years ago:

"Restriction of controls" is an important new trend in aviation. It is the main principal of all the simplified, "family", "foolproof" airplanes - a simple mechanical stop somewhere in the control system that makes it impossible for the pilot to pull the stick back far enough to stall the airplane. The actual engineering of such a control restriction is not quite simple."

Wolfgang goes on to explain a bit about why the engineering of control restriction is "not quite simple." In the 1940's he and his colleagues lacked the technologies that Bernard Ziegler had available in the 1990's. But Wolfgang Langewiesche knew what needed to be done. In a real way, whether created intentionally or not, William Langewiesche's Fly by Wire is an homage to his father's foresight.

Both books - Highest Duty and Fly by Wire - are fine efforts and well worth your time. The authors have my admiration, for their words and more, for the ideas and values behind them.

Thursday, January 7, 2010

End of the Line for LORAN?

Before there was GPS, there was LORAN (LOng RAnge Navigation).

The Piper Archer II with which I was associated before N631S joined our family had a Northstar M1 LORAN-C receiver in its panel - a very nice and very useful piece of kit.

The LORAN didn't have a moving map, and it wouldn't tell you your position with a Circular Error Probability of 15 feet (more like a couple 10ths of a mile). But it was a wonderful aid to situational awareness under both VFR and IFR rules. I liked it very much.

Now, it is being reported that the LORAN signals will be turned off beginning in February, with termination to be completed in the Fall. According to the US Coast Guard:

In accordance with the DHS Appropriations Act, the U.S. Coast Guard will terminate the transmission of all U.S. LORAN-C signals effective 2000Z 08 Feb 2010. At that time, the U.S. LORAN-C signal will be unusable and permanently discontinued.

In the last couple of years there has been much discussion about the potential that an enhanced LORAN system (the so-called "eLORAN") would have as a backup to GPS. There are worries about the ability of the Air Force to keep the GPS satellite constellation fully populated, and the FAA is very desirous of shutting down most (or all) of those expensive-to-maintain VOR's. But the Coast Guard is taking the position that:

If a single, domestic national system to back up GPS is identified as being necessary, the Department of Homeland Security will complete an analysis of potential backups to GPS. The continued active operation of Loran-C is not necessary to advance this evaluation.

I'm sure that the old LORAN-C equipment has become devilishly difficult and costly to maintain, and that there is a very good rationale for pulling the plug on it. But that does leave us with a lot of our eggs in the GPS basket. We had better watch that basket really closely. And I expect that as long as N631S and I are flying together I'll be dialing in VOR frequencies as backup to GPS navigation.

So let us bid a fond farewell to the faithful LORAN-C system. It had a good run and, who knows? Someday we might see the technology resurrected in modernized form.