The flight instructor reported that, during an instructional flight at an airport in Toms River, New Jersey, he told the student to set up for landing on Runway 6.
When they were at an altitude of about 400 feet above ground level, the flight instructor told him to apply full power for a go-around.
When the student applied full power, the Cessna 172’s engine did not respond.
The flight instructor took control of the airplane and tried to land on Runway 24. He knew they would not make the runway, so he tried to land in the grass.
The left wing hit a fence and flipped the airplane over, which resulted in substantial damage to both wings, the vertical stabilizer, and horizontal stabilizer.
The flight instructor stated that he thought the throttle cable had become disconnected.
A post-accident examination revealed that the throttle cable was not connected to the carburetor. An AN drilled bolt was found at the bottom of the cowling, however, the castellated nut was not located.
Review of the maintenance logbooks revealed that the engine had been recently overhauled and installed in the airplane.
Further conversations with the flight instructor, who was also the mechanic, stated that it is possible he forgot to install the cotter pin into the castellated nut and the bolt fell out.
Probable Cause: Loss of engine power due to the throttle linkage becoming disconnected in flight due to improper maintenance.
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This May 2022 accident report is provided by the National Transportation Safety Board. Published as an educational tool, it is intended to help pilots learn from the misfortunes of others.
DISCLAIMER: “An aircraft owner, pilot or an A&P/IA have one thing in common, we are human, subject to making mistakes.” As a former Commercial instrument rated Army helicopter pilot with several thousand hours & a single engine land airplane private pilot, I have experienced missing steps while performing preflight inspections. Bolts loose, safeties missing, tools left in various place after work has been completed & “signed off”. In the military you have the grunt doing the actual chore, his “boss” verifing the work was completed, then a “qualified” Tech Inspector, (TI) verifiy work completed & the TI releases aircraft for flight. In the civilian world, you have the A&P doing the work & for much of his job, he does the work, signs off his work & releases the aircraft. Annual & 100 hour inspections, major component overhaul/changes, an A&P and an IA both check work, completion, & if complete, both make entries in the logbook. A one man shop, an A&P/IA does the work, inspects his handi-work, signs off the logbook. In this case, engine overhauled or change by an A&P, did not say IA but is a CFI, probably using his own aircraft, did the requirements of three (3) seperate people, & missed the critical cotter pin in throttle linkage. There are many qualified A&P/IA’s in a single man shop, which I have no issue with. However, there is only ONE set of eyes checking the work performed. In this case, that is probably the issue.
INTERRUPTIONS – This might make a good case for parking all cell phones in the OFFICE. Don’t worry; if it’s important, they will leave a message or call later.
When working, I always keep a DO LIST in my immediate reach to jot down anything like cotters or safety or anything else that cannot be completed RIGHT NOW.
MEMORY does not improve with age either!
Jerry King
You seem to have an age fixation. As an employer for the last 50 years, in fields including mechanical, I find the younger folks to be generally less competent, knowledgeable, and unable to use common sense.
Not easy to find a good mechanic
Aircraft owners and pilots need to be mindful that maintenance Errors create significant hazard and must act accordingly the most likely time for an aircraft to suffer mechanical problem is on the first flight after maintenance be thoroughly Skeptical anytime Aircraft comes out of the shop your preflight and post flight maintenance test flight or last line of defense against maintenance errors
It is seldom the big things that get you, but the little ones. It is every mechanics nightmare that he will miss some little thing like a cotter key. It is interesting that you can get a A&P certificate with a passing grade of 70%, but is expected to do a 100% job. It is a goal we all strive for, but I will bet if you have never made a mistake, you have never done a damn thing. So far after 57 years, the mistakes I have made have been found and corrected before something bad happened.
And this is why aircraft must be maintained ONLY by Certificated Airframe and Powerplant mechanics ….
The instructor is an A&P, and admitted that he may have not secured the hardware.
The CFI was also an A&P per the logs…. And he also held a flight engineer rating.
JimH: I like that idea, safety wire the bolt to the throttle arm….
Meanwhile, after a certain age (depends on the person), inspection check list(s) needs to be done to be sure you didn’t forget something. Example: A phone call at the wrong time could have been what led to this castle nut not being tightened and cotter pinned.
Cotter pin is secondary
Primary is the bolt and nut weren’t tightened properly and wouldn’t need a cotter pin in the first place since this isn’t a preload setting.
I have seen a number of engine nuts back off that did not have a cotter pin or lock washer, that were originally properly tightened.
Even a 6 cylinder a/c engine vibrates a lot.
My Vermeer 800 rock trencher vibrates a lot, as in bouncing 42,000 pounds into the air.. Nothing is cotter pinned, nothing falls off.
Yet another aircraft wrecked because of a missing $0.05 cotter pin.!!
It may be a good idea to safety wire the bolt to the throttle arm…just in case the nut is lost.
Also, the pilot could have pulled the mixture to cut the engine power and land on rwy 6, in the remaining 3,000 ft, if he was actually 1/2 way down the runway at 400 ft.!!…poor piloting.!
Where did you read that the plane was halfway down the runway? I see only that the plane was 400 AGL when a go around was attempted when they lost throttle control. Looks to me that they were on final. Obviously, if they were over the runway, the CFI would have had no problem landing and would not have hit the fence on the approach end while trying to make the grass.
Disregard, Jim. I read the full report.
I’m with you, Jim. As an A&P, I always THINK about super important items that HAVE to stay together. I’ll sometimes do exactly what you said … use safety wire as a backup.