FLYING LESSONS for August 1, 2024

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FLYING LESSONS uses recent mishap reports to consider what might have contributed to accidents, so you can make better decisions if you face similar circumstances.  In most cases design characteristics of a specific airplane have little direct bearing on the possible causes of aircraft accidents—but knowing how your airplane’s systems respond can make the difference in your success as the scenario unfolds. So apply these FLYING LESSONS to the specific airplane you fly.  Verify all technical information before applying it to your aircraft or operation, with manufacturers’ data and recommendations taking precedence.  You are pilot in command and are ultimately responsible for the decisions you make.     

FLYING LESSONS is an independent product of MASTERY FLIGHT TRAINING, INC. ©2024 Mastery Flight Training, Inc.  All rights reserved.  

This week’s LESSONS:

AVWeb reported a fuel leak this week. Normally such a discovery would not warrant widespread media (or any media at all). This fuel leak, however, was on the underside of a Beech C55 Baron leased by the Aircraft Owners and Pilots Association (AOPA) and being used as a flying demonstrator of General Aviation Modifications, Inc.’s (GAMI’s) G100UL unleaded 100 octane aviation gasoline. The Baron demonstration involves comparison testing of this (relatively) new Supplemental Type Certificate (STC)-approved fuel in the left engine fed by left-wing fuel tanks, with standard 100LL avgas in the right engine and that engine’s right-wing tanks. I’ve had the opportunity to fly in the AOPA Baron test and found G100UL to work as advertised, at least during my very short experience with AOPA’s fuel-demo pilot. 

AVWeb’s photo of the AOPA-leased Baron’s fuel leak

The fuel stain found while the airplane was on display at Oshkosh is on the underside of the left-wing tanks. The implication—mere speculation at this point—is that the leak might be the result of contact with something in the unleaded fuel. Fuel bladder leaks in Barons are common as components age, however, as are leaks in fuel seals and gaskets around line connections, fuel level transmitters and other parts. Maintenance experts suggest replacing the rubber fuel bladders at 20 years in service and some sources say the AOPA-leased C55 fuel bladders have twice that time in service. Absolutely, the cause of the leak must be determined and G100UL fuel eliminated (or, however unlikely, confirmed) as its cause.  

But that’s not the LESSON I draw from AVWeb’s report this week.

Say you flew your airplane to Oshkosh, or somewhere else. While on the ground there you spot (or someone points out) a fuel stain on the underside of your aircraft. Or maybe it’s a wrinkle in the wing skin, or a minor crack along a fuselage rivet line, or a cracked windshield. Whatever the particulars, you become aware of a discrepancy…far from home. 

Do you leave the festivities to contact a mechanic, and arrange to have your aircraft evaluated? Or do you rationalize the discrepancy, perhaps come up with some sort of mitigation you think will reduce the risk as you fly the airplane home to have your regular mechanic check it there?  

If you do get a mechanic to check it out, and he or she tells you “You definitely need to get that fixed, but it should be okay to get you home,” do you accept the advice? 

Bear in mind that from memory I’ve reported on at least two Bonanza wing explosions, one Baron wing explosion and one explosion of a wing on a Beech Queen Air over the years in my Beech Weekly Accident Update—all, thankfully, occurring on the ground—that were eventually attributed to leaks in wing fuel tanks or lines ignited by electrical wiring passing along the wing leading edge where fuel components are mounted. In most of these events the explosion occurred immediately when the pilot turned on the strobe lights prior to takeoff. I seem to recall similar events reported in twin Cessnas, and I expect it’s happened in other airplane types also. But I don’t currently follow non-Beech accidents and incidents as closely.

It’s easy sitting in my home office writing this report to say, “No, I’ll ground the airplane until the discrepancy is repaired.” It’s easy to say the same reading this blog at zero airspeed and one G, with no pressure—real or self-imposed—to fly home. 

But how easy would it be to make that same call hundreds of miles from your home as all your friends fly away and you really need to get to home and work? 

That’s my FLYING LESSON this week: As you consider this scenario without the stress of the actual moment, how will you maintain the discipline to resist temptation (and even a mechanic’s suggestion) to brush off what could be a major hazard? What can you decide now to make it easier to make a good decision then?

Questions? Comments? Supportable opinions? Let us know at [email protected]

Debrief: 

Readers write about recent FLYING LESSONS

Reader Jim Piper writes about my most recent LESSONS:

Regarding use of Approach flaps for their designed purpose, I’ll have to try to video the airplane’s response to partial flaps and normal power reduction from downwind in the pattern some day. Regardless, it’s the difference between procedure and technique. The correct procedure is “extend the landing gear before touching down on the runway.” There are any number techniques to assure that procedure is completed, which I’ve addressed here and elsewhere for 34 years. I accept that different people do things different ways. The ultimate solution: regardless of whatever else you do, confirm gear extension before crossing the runway threshold every time, and go around immediately if the gear is not confirmed to be down, without hesitation.

To your second point, that is very type- and even model-specific, as well as variable for a specific aircraft based on its weight and the current environmental conditions. Notice that Beech calls the preselectable partial flap position approach flaps, and not takeoff flaps. Thank you, Jim. 

Read Jan Jansen also writes about the July 18 report:

True, to “take off” is a verb while “takeoff” is a noun. Perhaps the NTSB, which I was quoting directly in the excerpt you cite, needs to learn that (note I put longer quotes in blue font to distinguish others’ words). Not that I don’t sometimes make mistakes in these after-hours musings, so thanks for keeping me precise, Jan.

South African reader Bernard Monteverdi adds to the July 18 LESSON:

Given that flap extension is not critical to takeoff in your particular aircraft type—in fact, it’s discouraged—might you eliminate the preflight test altogether and avoid the risk of forgetting again? You could make a periodic test after landing, or even in the hangar. I favor doing these sorts of checks when I’m not planning to fly and pressured to rationalize a discrepancy to get in the air. If you find a problem while in the hangar you have time to address it before your next flight, or make other travel plans if you cannot. I do appreciate your diligence in adjusting technique to mitigate a hazard. Thank you, Bernard.

More to say? Let us learn from you, at [email protected]

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Disclaimer

FLYING LESSONS uses recent mishap reports to consider what might have contributed to accidents, so you can make better decisions if you face similar circumstances. In most cases design characteristics of a specific airplane have little direct bearing on the possible causes of aircraft accidents—but knowing how your airplane’s systems respond can make the difference in your success as the scenario unfolds. Apply these FLYING LESSONS to the specific airplane you fly.

Verify all technical information before applying it to your aircraft or operation, with manufacturers’ data and recommendations taking precedence. You are pilot in command, and are ultimately responsible for the decisions you make.