Whose fault? — General aviation news

That was a pretty thing, Cherokee. Glossy white, with two-tone red stripes on the wings, fuselage and tail, his gear is wrapped in wheelie pants.

It had been owned by one person for the past 20 years without incident, and yet, nine months after being sold to a new owner, the Cherokee was a crumpled pile of junk sitting in a ditch at the end of Runway 24 at the Oswego County Airport. (KFZY) in Fulton, New York.

The NTSB placed the blame for the crash solely on A&P/IA, which had completed the plane’s first annual course under its new owner just three days before the crash.

However, a closer look at the details surrounding the plane’s destruction reveals that the damage may be more than enough to spread.


We don’t have a record of how long the plane was in annual mode, but as any owner can tell you, all annual periods are too long — and in this case, quite a bit of extra work was done, so there probably wasn’t a quick turnaround.

But after a year, the owner picks up his plane at Cortland County Chase Field (N03) in Cortland, New York, and begins a ferry flight to its KFZY home base approximately 46 nautical miles away.

As he takes off, he notices that an oily film is beginning to form on the windshield. It starts at the bottom of the glass near the hood, mostly on the co-pilot’s side, and quickly moves 5 or 6 inches up the glass. But then it seems to stall, so instead of turning around and heading back to the maintenance shop – which is still the nearest airport – he decides to continue his flight home.

You thought that was when the accident would happen, didn’t you?

No, not yet. The gods of flight smile upon our hero and he returns home safely.

The next day he calls Internal Affairs, who tell the pilot not to fly the plane and that he will come over and check it out.

But the pilot decides to check it himself. He opens the hood and sees no oil. He cleans the windshield and accelerates. Then, according to his handwritten statement to the NTSB, “I saw some oil spots, so I decided to take off and land.”

You thought that was when the accident would happen, didn’t you?

The pilot and the accident

No, nothing terrible happened, as the flight gods smiled again on our hero, a 68-year-old man with a private pilot certificate and about 170 flight hours, only 13.3 of which were on makes and models.

On the third day, he decides to do the same. But this time he is not lucky.

After takeoff, “the oil started covering the windshield,” he told investigators.

It took off from Runway 15 at KFZY and makes a hard left bank to go around and land on a perpendicular runway 24. It climbs high and hot, touching halfway down the nearly 4,000-foot runway, and can’t stop before the end.

Its tour of the runway extends more than 360 feet past the threshold, where it cuts through the airport’s chain-link fence, removing three vertical posts in the process, and comes to rest in a ditch 30 feet beyond the fence line.

The pilot received only minor cuts and bruises. The plane, however, is mortally wounded.

The plane after the accident. (FAA photo)

Oil leak

At the crash site, an FAA inspector reported that there was no significant amount of engine oil on the cylinders or hood accessories, but that oil coated the surface of the fixed pitch rack, spinner, and nose cowl.

Crankshaft with crankshaft cap missing. (FAA photo)

The plane is moved to a hangar where an inspector removes oil-covered parts “to try to determine the source of the engine oil leak,” and as he does so, “the plug installed in the front engine crankshaft bore fell off. to the ground.”

NTSB investigators determined that an oil leak was the cause and thus ultimately the cause of the crash.

The plug is formally called a crankshaft expansion plug, and if you think of it as a cork in a wine bottle, you’re not far off. Only the bottle, in this case, is a Lycoming O-320 hollow crankshaft.

Crankshaft box. (FAA photo)

Why did he move?

The NTSB’s final accident report states that “the mechanic who performed the maintenance stated that he installed the crankshaft plug using a ball hammer instead of following the procedures outlined by the engine manufacturer, which requires the use of a special tool. to properly deform and install the plug.’


The special tool is called the Lycoming Driver Crankshaft Welch Plug, which Aircraft Spruce is listing for a staggering $1,677 each.

It’s kind of like those tools you use to install clothespins, you know, the ones you hammer to close the metal. And you’re also hammering away at a $1,677 tool, but apparently the mechanic decided to cut out the middleman and just use a hammer.

Tool. (Photo courtesy of Lycoming)

When an FAA inspector arrived at the workshop to interview him, the inspector described the mechanic as “polite and cordial.” But then things start to get worse.

When the inspector asked to see the technical publications he used, the mechanic “replied that all the technical data for the shop was on his computer at home and was not available.” When asked to produce his IA and A&P certificates, the mechanic “informed the inspectors that he did not have them with him, even though he was actively exercising their privileges and was in the process of conducting an annual inspection on another aircraft.”

The mechanic’s bad day ended with the FAA inspector giving him a copy of the Pilot’s Bill of Rights and telling him to wait for a Letter of Investigation from the FSDO.

Ironically, in the airplane’s engine accident log, above the standard, “I certify that this engine has been inspected in accordance with the annual inspection and has been found to be airworthy,” the mechanic entered the following disclaimer: “The following statement in in no way implies or guarantees that this engine will continue to operate for any period of time after this inspection.”

The NTSB came down with the hammer on the mechanic, citing “improper maintenance by the mechanic that caused the crankshaft spacer plug to dislodge during the flight and subsequent forced landing” as the probable cause.

The pilot was not censured for his actions by the NTSB.

Analysis and discussion

The mechanic used the wrong tool, apparently didn’t keep his technical data in the same building where he worked, and didn’t know the rules well enough to realize he needed to have the certificates in his wallet. You can’t protect yourself from it.

Sure, this tool is expensive, but every five years it’s used to perform ADs on a large family of engines found on a wide variety of aircraft, including Cherokees, Super Cubs, and Cessna 172s.

But balancing that, he told the pilot not to fly and that he would come to the pilot’s seat to check the plane.

So now we have to watch the pilot.

Keep in mind the Spider-Man rule, 14 CFR 91.3, which states that “with great power comes great responsibility.” Well, it actually says that the PIC “has direct responsibility for the operation of the aircraft and is the final authority”.

So did the pilot show a good quotient of responsibility when he flew home with oil crawling on the windshield instead of aborting the flight and returning to the field? Did the pilot show a good quotient of responsibility when he ignored the mechanic’s request not to fly the plane? Did the pilot show a good quotient of responsibility when, despite the more mysterious oil “spots” on the windshield, he flew again. Twice?

Now, admittedly, this is a complicated oil leak. It goes up the hollow crankshaft and out past the spinner, leaving the engine bay clean. It’s a fixed-pitch rocker arm, so it’s possible the pilot didn’t even know the engine had a hollow connecting rod.

But still the plane was talking to the pilot, and the pilot – the ultimate authority – was not listening.

A view of the oil leak in the nose cone. (FAA photo)


We pilots are often caught between a rock and a hard place with 91.3. Consider the fledgling private pilot. Although he most likely does not own the plane, is prohibited from performing most of the maintenance, and probably does not understand the inner workings of the plane’s systems, this new pilot is still the final authority on its airworthiness.

The NTSB, uncharacteristically, hung its hat solely on the mechanic in this accident.

But the question for debate is, should it all be on the mechanics, or does the pilot – in this case – share some of the responsibility?

Want to learn more?

Download the NTSB final report here or view items in the list here.

https://generalaviationnews.com/2022/11/21/human-factors-whose-fault-really/ Whose fault? — General aviation news

Back to top button