Circuit Breaker Safety

I recommend the Flight Safety Information newsletter sent out by e-mail each day from Curt Lewis & Associates, LLC. They are a consulting organization based in Arlington, TX and specialized in aviation and industrial safety. You can and should subscribe to their useful and interesting newsletter at the FSInfo.org web site.

The other morning the newsletter drew my attention to a recent article from Business and Commercial Aviation. It commented on conclusions drawn by the NTSB after their investigation of the fatal July 2007 crash in Sanford, FL of a Cessna 310R. This aircraft was owned and operated by the NASCAR organization. The newsletter item led me to find and read the NTSB Final Report on the accident.

The report discusses a number of lessons learned from this accident. The one that I took special note of related to Circuit Breaker (CB) Safety. It's widely accepted in the general aviation world that when a CB trips it is acceptable practice to re-set it once. The rationale, of course, is that if the cause of the CB's tripping was a transient event all will be well, and if the cause persists the CB will trip again -- and all will be well! The NTSB demurs.

The report makes for interesting reading, but let me here offer a few pertinent quotes:

• Circuit breakers are installed on aircraft to protect wiring. [Emphasis added] When current flow in a system exceeds a predetermined value for a period of time, the circuit breaker activates, or “trips,” to stop current flow through that system by breaking the electrical circuit. To use the system after a circuit breaker trips, a pilot must reset that circuit breaker manually. Historically, it has been common practice to reset a circuit breaker on an airplane one time after the breaker trips. ... However, this practice does not consider the cumulative nature of wiring damage and that the removal of power only temporarily stops the progression of the damage. The aviation industry has begun to recognize the potential hazards of resetting noncritical circuit breakers even once.
• Quoting the FAA's 2004 AC 120-80 on "In-Flight Fires": Crewmembers may create a potentially hazardous situation if they reset a CB without knowing what caused it to trip. A tripped CB should not be reset in flight...unless, in the judgment of the captain, resetting the CB is necessary for the safe completion of the flight. [Emphasis Added]
• [M]any Part 91 pilots and operators have not yet made changes to address current guidance about circuit-breaker resets. ...[M]any general aviation pilots, mechanics, and operators may not have reviewed AC 120-80. ...the guidance contained in manuals provided by general aviation airplane manufacturers often directly conflicts with the guidance contained in AC 120-80. ...general aviation pilots, mechanics, or operators who did review the AC might not have perceived its relevance to their operations.
• The Safety Board concludes that existing guidance in manuals provided by general aviation airplane manufacturers regarding the resetting of circuit breakers often does not consider the cumulative nature of wiring damage and that the removal of power only temporarily stops the progression of such damage. ...if general aviation pilots, maintenance personnel, and operators had a more thorough understanding of the potential hazards of a reset circuit breaker (as outlined in AC 120-80), they would be less likely to reset a tripped circuit breaker without knowing what caused that circuit breaker to trip. ...the FAA should develop a safety alert for operators (SAFO) informing general aviation pilots and maintenance personnel of the circuit breaker policy contained in AC 120-80. ...the FAA should require that the contents of the SAFO ... be included in initial and required biennial training for general aviation pilots and maintenance personnel.

Going forward, I do not believe that I will re-set a tripped CB in flight even once unless I am really sure that I know why it tripped (and I judge that cause to be benign) or I really, REALLY need electrons to continue to flow to the device down-wire from that CB...and, frankly, it's pretty hard to conceive of a situation on N631S where that would be the case.

Both the NTSB report and the In-Flight Fires Advisory Circular (linked above) are recommended reading.

Liberty Belle in Connecticut

When I landed at KBDR yesterday this gorgeous creature was on the ramp. (Thanks to David and Matt at Three Wing for the photo):

If you visit the web site maintained by the Liberty Foundation you can learn all about the interesting history of this B-17G and also discover that rides and ground tours will be available on Saturday 8/1, at Hartford-Brainerd (KHFD) and on Sunday 8/2 at Sikorsky Memorial (KBDR).

The Quickest Thing May Be to Slow Down

N631S and I departed KBDR at 2107Z last evening for the weekly trip to DC. I'd had a quick look at the weather radar shortly before departure and was aware that there was convective activity west of Harrisburg that would bear watching.

My clearance was the usual one generated by the ATC computer: Radar vectors to SAX, thence V249 SBJ V30 ETX V39 LRP V93 BAL, thence direct to destination VKX.

Soon after departure I figured I'd better see what was going on with that weather that had been west of Harrisburg, so I switched the Garmin GPSmap 396 to the NEXRAD weather radar page and panned the map to the eastern Pennsylvania portion of my route. At 2200Z, it looked like this:

It's fair to say that it had my attention. I knew from earlier conversations with Flight Service that the whole system was moving eastward, but not all that quickly. My thought was that I should not be in any hurry to get to Lancaster...instead I should give that chunk of nasty weather ample time to clear to the east.

I was at 8,000 feet MSL running lean at 11.8 GPH and getting 137 KTAS. I further leaned the fuel flow, adjusting trim as needed, until the big Continental was running on 10.7 GPH and giving me about 130 KTAS. That probably stretched my time en route to Lancaster by 10 or 15 minutes. I also knew that the last controller from New York TRACON would offer me a shortcut "direct LANNA" and then the Allentown Approach controller would offer "direct FLOAT". I planned to (and eventually did) decline both of those shortcuts, giving me perhaps another 10 minutes enroute.

This all worked semi-splendidly. By the time I turned south at ETX most of the really intense precipitation and all of the lightning had cleared to the east. There was a patch of moderate precipitation to be negotiated between Reading and Lancaster but that proved not to be too uncomfortable.

A word of appreciation is in order for the controller at Allentown Approach. He could see the significant precipitation returns south of Reading on his radar and before he handed me off to Harrisburg he made it a point to be certain that I had equipment on board that would let me see and if need be, avoid that weather. Full points! I suspect that this concern is the result of the Scott Crossfield accident...but I appreciate it nonetheless.

As I crossed over the Lancaster airport the weather was clearing but my NEXRAD display was still showing lots of action to the south-southeast. I asked the Harrisburg Approach controller to coordinate with Potomac Approach so that I could continue on a southwest heading until I was assured of missing the "tail" of the convective activity before turning southeast toward Baltimore. The great folks at ATC made it all happen and it wound up like this:

At that point all of the drama was over. The remainder of the flight into VKX was routine. Here's the Flight Aware track for the entire flight.

The Long Way Round

This morning there was quite a bit of fairly ominous-looking weather over much of New Jersey so I decided to try a northbound route over eastern Pennsylvania. This lead to a swing to the north via the Huguenot VOR (HUO) and the Kingston VOR (IGN) before approaching KBDR from the north.

That last patch north of Bridgeport showed up as mostly yellow with a few flecks of light orange on the Garmin/XM display. It offered moderate rain and a tiny bit of light turbulence.

This was the METAR as I was flying the ILS 6 instrument approach:

KBDR 211452Z 04008KT 9SM -RA OVC014 18/17 A3015 RMK AO2 SLP211 P0005

Good visibility in light rain with a 1,400 foot overcast. I actually broke out of the overcast at 1,100 feet.

I LOVE Air Traffic Controllers!

Have I mentioned how much I love Air Traffic Controllers? When things get, er, interesting - as they did last evening - there is nothing more reassuring than the calm, professional voice of a skilled controller working the situation along with you.

The summer afternoon standard-issue convective weather was kicking up its heels over eastern Pennsylvania as I launched from KBDR; wheels off the runway at 2120Z. My IFR clearance was for the usual routing: SAX V249 SBJ V30 ETX V39 LRP V93 BAL Direct, at 8000 feet. I was watching the NEXRAD weather radar picture from XM Weather on the Garmin GPSmap 396 and planning a strategy for working between and around the nastier looking bits.

Shortly after turning south at Sparta VOR (SAX) the New York controller gave me a small shortcut to LANNA intersection on V30. It was 2159Z and the picture looked like this:

Before the shortcut to LANNA I'd been headed to SBJ, well clear of the storm cell west of my track heading northeast. Before accepting "Direct LANNA" I'd looked carefully at that and concluded that the resulting track was still going to keep me out of trouble with that one.

At that point I shifted my focus to the cell that shows up south of the airway west of LANNA - that's V30. In the picture above it's partly hidden by the track readout "237" but it was headed in a threatening direction.

Just about then, the New York controller said, "31 Sierra, contact Allentown Approach on 124.45." Before checking in with Allentown I looked at the weather situation. The prudent thing to do would be to continue toward LANNA until clear of the cell to the west, then turn behind it to the west so as to miss the one up ahead. I transmitted, "Allentown Approach, Skylane 631 Sierra, level 8000 with a request." That got me an immediate, "631S, Allentown altimeter 29.75 and what is your request?"
I said, "In about 15 miles 31 Sierra will need direct FJC, then direct ETX to rejoin V39, for weather avoidance." The lady said, "31S that will be approved...you may not need it when you get there."

I settled down to watch the weather evolve and listened as the controller did a masterful job of using her radar weather depiction (Approach Control Radar reportedly has pretty good weather capability) and her complete grasp of what each airplane in her airspace needed to keep the potentially chaotic situation under perfect control. Controllers would say of her, admiringly, that "she had the flick."

The cell I was watching continued to move into my path and just as I was about to key the mike and ask for a diversion the controller transmitted, "Skylane 31 Sierra, cleared direct to the Allentown VOR." I immediately entered Direct FJC into the GPS that was driving N631S and turned away from the storm cell. It was about 2222Z and the situation looked like this:

About halfway to FJC I was wondering when to ask for "direct ETX" when my favorite controller said, "Skylane 31 Sierra, from your present position it looks like a straight shot to East Texas will miss all the heavy precipitation. What do you think?" I figured I'd probably catch just the edges of the moderate precip, but was well past the core of the cell, so I responded, "31 Sierra thinks direct East Texas now will be fine." She said, "31 Sierra, cleared direct East Texas."

I did fly through some moderate rain, and minimal turbulence - no big deal. As I flew toward ETX I continued to be impressed by the lady's work, sending airplanes where their pilots needed to go, advising that some requests for re-routes were a Bad Idea and generally doing a fantastic job at a busy time. And I never heard even the tiniest hint of stress in her voice.

Soon, she said, "Skylane 31 Sierra, contact Harrisburg Approach on (some freq) and have a good evening." I thanked her for her help and said, "Great job!" Minutes later I was out of the precipitation and dealing with clearing skies over Lancaster.

Today, I'm working on tracking down an e-mail address for the manager at Allentown Approach. I want to let them know that the lady on 124.45 at 2200Z last night is one terrific controller.

Flight Review

Non-cognoscenti find it amazing that the only requirement for recurrent qualification imposed on the holder of a Private Pilot License is the accomplishment every 24 months of a Flight Review to be administered by a CFI. The regulations define the Flight Review, in 14CFR61.56(a), thus:

"...a flight review consists of a minimum of 1 hour of flight training and 1 hour of ground training. The review must include...a review of the current general operating and flight rules of part 91 of this chapter; and...a review of those maneuvers and procedures that, at the discretion of the person giving the review, are necessary for the pilot to demonstrate the safe exercise of the privileges of the pilot certificate."

For a long time, I took advantage of a waiver to this requirement that was incorporated in the WINGs Program. The enabling document said, in a nutshell, that if you spent three hours flying with a CFI and attended one FAA-recognized aviation safety event within two years your Flight Review requirement would be considered fulfilled and you'd get a nifty little pin for your hat.

A little more than three years ago the FAA destroyed the WINGs program by making participation much more complicated and adding onerous verification requirements. It just became easier to go get a Flight Review.

Last summer I did just that, with my friend and long-time instructor Bob Parks. I'm not required to do it again until next summer...but I like the idea of applying some Quality Control to my aviating a bit more often so I decided to get another Flight Review this summer. But that presented a problem - with whom? My pal Bob became ill (and recently "went West") so I needed a new instructor.

Starting a relationship with a new CFI is just about as challenging as getting acclimated to a new barber. Styles and approaches differ, and as much as the FAA would like to claim that instruction and evaluation are standardized, personal characteristics matter. I've gotten to know a young (compared to me) instructor at Three Wing Flying Services named Jared. He's easy to talk to and seems pretty pragmatic in his approach to things so I asked him if he'd do a Flight Review with me and he agreed.

Jared and I started with the hour of ground instruction and we finished up the Flight Review on Tuesday evening with an hour aloft in N631S. It was fun to scrape the rust off of some neglected "stick-and-rudder" skills with steep turns, stall series, simulated emergencies and pattern work. (I do wish I could take back one landing. I'm again grateful for Cessna's hell-for-stout landing gear.) Jared proved to be as calm and good-natured in the aircraft as he is in the hangar. I will happily fly with him any time.

I surely do miss Bob Parks. But life goes on. I suspect Jared and I will be doing another Flight Review in a year.

Maintenance Odds-'n'-Ends

My good friends at Three Wing Flying Services (at KBDR, and I recommend them highly and without reservation) finally managed to print maintenance log stickers for the last couple of times they laid wrenches on N631S. (It seems that they were afflicted by a computer system virus that, among other effects, trashed the driver for their thermal printer.)

The first item was an oil change, accomplished at the same time that they installed the Cessna seat-stop modification. It being summer, we put in Aeroshell 100W oil, as opposed to the Aeroshell 80W that the engine runs on in cooler weather. I've now been following this routine for about 500 hours and the engine seems to be loving it.

I always have a spectrographic analysis done on a sample of the used oil and it has come back from the lab as normally unremarkable.

The second item was triggered by one of those "hmmm" moments during my run-up a couple of weeks ago before a flight from VKX up to KBDR. After taking the engine RPM up to 1,700 and getting a good magneto check and good propeller pitch cycling, I pulled out the knob for the carburetor heat and...nothing happened. Not too good.

The wonderful Continental O-470U engine that pulls N631S along does have one important idiosyncracy. It is an ice maker that would make the Frigidaire folks proud. The carburetor is mounted on the bottom of the engine and the throttle body stands well off under the crankcase, in a comparatively cool environment. As a result, the carb is prone to the accretion of ice in the venturi section. When that happens it can choke off the flow of combustible stuff into the cylinders and the engine stops running. This can be inconvenient at any altitude greater than about 2 feet AGL. The cure for carburetor icing is to provide a valve that diverts the incoming air flow past the nice hot exhaust plumbing, thus preheating it and making ice accretion unlikely. If the carb heat is not working as designed you are left without a weapon to combat carb icing.

On the morning in question, the sky was clear and (more importantly) the humidity was low (i.e., there was a good spread between temperature and dew point). So I assessed the risk of carb icing as minimal and made the flight to KBDR. On arrival I asked the nice folks at Three Wing to take a look at N631S's carb heat valve.

The valve in question is a squarish plate that rotates open or closed on a shaft turned by a bell crank attached to a cable that is pulled by the control knob in the cockpit. In this case, the fasteners that attach the valve plate to the shaft had sheared. I guess after 32 years and 3,750 hours this kind of thing can happen. Tony at Three Wing opened up the carburetor air-box assembly and re-secured the valve to its shaft.

The last item involved the electric pitch trim control. For a while I had been not liking the feel of the yoke-mounted thumb-switch that actuates the pitch trim. It had developed a "sticky" spot. So I asked Dave at Three Wing to look at it. He agreed that it wasn't right and ought to be replaced.

The reason this matters is that the switch might fail in one of its "ON" positions and cause a runaway trim actuation. If this happens at an awkward time (say, just after takeoff) things can quickly get a bit too interesting.

The bad news is that the manufacturer wants $495 for a new switch! (No, it isn't made out of gold - just priced that way.) So for the time being, I have elected to render the electric trim option INOP and make do with manual trim adjustment. I am on the lookout for a used switch and meanwhile Three Wing pulled the electric trim circuit breaker and made a nice little placard saying "Electric Trim Inop".

Robert J. Parks, CFII (1922-2009)

My instructor, my mentor, my friend went West last night after a long, eventful life and a mercifully brief decline. He was 87 years of age, and 67 years a flight instructor.

Bob soloed in an Aeronca C3 on floats in 1939. He served his country during WWII in the CPT program and in the USAAF, attaining the rank of Captain. He went on to a rewarding career in business, but always stayed involved in instructing. Last year he received the FAA's Wright Brothers Award for those with over a half-century of contribution to aviation.

My mind does not usually work in verse, but for some reason as I tried to put my feelings about Bob's passing into words this is what came out:

Requiem for an Aviator

For Robert J. Parks, CFII (1922-2009)

Somewhere far, far to the West – almost beyond where the sun goes to rest
After flecking the clouds with pink and gold hues,
An airfield lies nestled in a valley, under clear blue skies.

The grass strip is home to machines of wood and fabric, wire and dope,
With round engines and spruce props turned by AvGas and the hope
That it won’t quit now – but out there it seems they never do.

Every now and again a new one drones in from the East – there’s always a tiedown
For at least one more, and the guys hangar-flying near the line shack door
Pause and look up as a biplane comes into view above the hill.

The pilot overflies the field, to see what the wind will do, and banks onto the downwind.
He turns base and final, squaring the turns and slipping down to the flare,
Scrubbing off altitude he’d kept in the bank in case the old Continental picked then to tank.

Reacting to the gentle crosswind flow he holds the upwind wings a bit low,
And pulls the stick back, landing in a full-stall. Rolls out, taxis back,
With his sinuous track letting him see past the cowl. “A Waco UPF-7”, somebody says.

The old Waco’s paint is faded and stained but it’s a neat bird, it looks well maintained.
They watch as the flyer taxis around to a tiedown, pulls the mixture, shuts down.
And he climbs out, lithe, agile, with youth rediscovered, and hops to the ground.

As he sheds his leather jacket he hears his name called. “Hey, Parks, where’ve you been?
We’ve been waitin’ for you.” He grins and calls back, “You old reprobate, Lou.
The Teterboro crowd is here? The Ramapo gang, too?”

“You bet. Have some coffee. We’ll get caught up soon enough. And you can tell us,
What the hell is this GPS stuff?” Bob chocks the old Waco and says, “Sorry, Lou,
But I’ve got to find Madeleine, and my grandson, too.”

“Go ahead, Bob,” Lou says, “We’re here every day. Come by in the morning.
The tanks will be full. The oil will be topped up and she’ll start, the first pull.
Bring your grandkid around. You can teach him to fly.”

With a glance at the sky, he walks through the gate – then runs to join the one who waits.
There’ll be no more cross-countrys, no reason to roam.
The pilot’s gone West; he’s found his way home.

The Giant's Alphabet

LOCATION: Central NJ along V16 between CYN and DIXIE (south of Lakehurst, over the Pine Barrens at 5,000 MSL.

TIME & DATE: About 9:30 AM local time on Monday, July 6th.

The unusual geometry of the ground features caught my eye. It looks like clearings have been created in the form of huge upper case letters. Like the giant's child spilled his toy box.

Anyone have any idea what this is all about?

"Somewhere, Over the Rainbow..."

At VKX on July 2nd, about 2:30 PM local. We'd landed a few minutes ahead of a rain shower that left behind this reward after passing through:

Just pretty...which, I think, suffices.

Composite vs. Base NEXRAD Images

A while ago in a post discussing Frontal Weather, I spliced in a number of NEXRAD images including one that showed the situation within a minute of the time I touched down at KVKX.

I commented that, "...these NEXRAD images show composite reflectivity and ... the surface weather was not as evil as the depiction just above would have you think." Let's take a closer look at that.

Below are two archival NEXRAD images showing returns seen by the Sterling, VA site at 2338Z on Friday, the 26th of June. I had landed at KVKX one minute earlier. The image on the left shows Composite Reflectivity; the one on the right shows Base Reflectivity.

If you enlarge the Composite (left) image by clicking on it, you'll see pretty intense returns very close to the location of the airport. You'd be thinking that I had cut things awfully close getting in from the east at that point.

Go ahead - click on it...then use your "Back" button to come back here.

Now, if you click on the Base (right) image, you get a different impression. The intense returns are still a fair distance away from the airport and there is even a clear band immediately adjacent to the field. In fact, there was no precipitation when I touched down. I had a pretty good margin. Have a look.

The NEXRAD weather radar system obtains a layered array of reflections in increments of 1/2 degree of elevation. The Base Reflectivity image is just the totality of reflections in the lowest 1/2 degree (i.e. pretty much horizontal). If you want to know what is going on near the ground you look at the Base Reflectivity image.

The Composite Reflectivity image is a synthesis that displays the most intense return obtained at any elevation above a given point on the map. So, if moderate precipitation exists 3,000 feet overhead, the system will paint the pixel corresponding to where you are standing yellow even if none of the precip is reaching the ground.

The NEXRAD image displayed on my Garmin GPSMap 396 (via XM Weather) shows Composite Reflectivity. (Note that the XM image is processed and synthesized a little differently than the National Weather Service (NWS) images shown above, but the principle is the same.) For cruise flight, you want a Composite Reflectivity image because that will give you "worst case" information and allow conservative decisions. If you were to rely on a Base Reflectivity image in planning your progress you could find a very unpleasant surprise waiting for you at 8,000 MSL.

Lots more interesting information on weather radar is available from NWS at this site. It's fascinating stuff and real-world useful. Highly recommended.

"Frontal Weather" Blog Images

Being fairly new at this "blogging" enterprise, I was perplexed when the images in my recent post describing Frontal Weather did not proffer an enlarged view when clicked -- since the images in older posts had behaved thus.

It turns out that cutting and pasting images within the Blogger editor risks severing the link from the image that appears in the post, and the "parent" image that resides somewhere in the Cloud on a Google server.

In any event, all of the images in that post are now enlargeable with a click. All fixed.