According to the pilot, he departed a private airfield near Justin, Texas, on a local flight about 30 minutes before the accident.
He told investigators that for the approach to landing, he applied carburetor heat on the downwind leg and reduced power on the base leg. When he added power, the Piper J-3 Cub’s engine did not respond, however the propeller continued to windmill.
Unable to glide to the private airfield, he selected a nearby wheatfield for the forced landing, but hit trees on the approach.
The airplane came to rest in the trees. An on-site inspection of the airplane by an FAA Inspector noted that the fuel tank contained fuel and both wings and fuselage sustained substantial damage.
The airplane was recovered from the trees and placed in the owner’s hangar. The National Transportation Safety Board Investigator-In-Charge who conducted an engine examination did not identify any pre-impact anomalies that would have precluded normal operations.
A review of the icing probability chart contained in FAA Special Airworthiness Information Bulletin CE-09-35 revealed that the weather conditions at the time of the accident were “conducive to serious icing at glide [idle] power.”
Probable Cause: The total loss of engine power due to carburetor icing.
To download the final report. Click here. This will trigger a PDF download to your device.
This March 2021 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.
Don’t expect the NTSB to expend much resource on GA events. They are in a sense one off, although repetitive with the same individual errors, be it pilot or maintanince.
Best they could usually do is say…don’t do that again!
Another benefit of a ‘power-on’ approach is that carburetor heat will be more effective, and this type of induction system icing will be less likely, compared to operation at “glide [idle] power”.
Is this 2023 or 1923? I’ve asked this question before and I’ll ask it again: Why can’t the function of carb heating happen automatically without pilot intervention? Simple temp and humidity sensors into a little microprocessor could handle the job. The pilot has all he/she can do to get that machine safely on the ground without worrying about an under-the-hood technical setting. That’s akin to the average driver worrying about the degree of spark advance in the engine. BTW: Early cars had a spark advance lever in the center of the steering wheel so the engine could be hand-cranked without breaking one’s arm when the spark was too far advanced. I see these scenarios as identical. One man’s opinion, worth what yo paid for it.
In the case of this aircraft, closer to 1923. You do realize you are calling for microprocessor controls for an aircraft designed and built from the late 1930s through until 1947 that was not equipped with a battery, generator, or electricity? A more modern aircraft typically has fuel injection which eliminates carburetor ice. Kind of like calling for the NTSB to require upgrades to your great granddad’s Hudson.
“There but for the grace of God go I.”
I’m not an A&P, so I am going to ask this question: Could something have been wrong with the carb heat system that heated air was not being supplied to the carb?
I ask this because I read the NTSB report. Assuming that the pilot had applied full carb heat, could there have been a problem that the inspectors didn’t catch?
I remember, years ago, in C15x trainers, that we put on carb heat on the downwind before reducing power and left it there. And even in NE Ohio with high humidity, I never experienced an ice-up of the carb like this guy apparently had.
I did have, once, where when we applied power (right after touch down) that the engine momentarily stopped, and then restarted. We stopped, and taxied in and it was figured that we had ice (this was at an airport in MD in a C150) that finally melted.
And this is why I ask my question.
I expect the NTSB views the pilot as less than truthful regarding the use of carb heat. However, to answer your question, if the Scat Hose from the heat exchanger to the carb heat box had come off, carb heat would have been ineffective. Another possible issue is that at idle, an A-65 produces very little heat in the exhaust, rendering carb heat to be relatively ineffective during an extended glide and allowing the carb to form ice under serious carb icing conditions. That’s why you are supposed to “Clear the Engine” periodically during an extended descent at idle when using carb heat. The act of throttling up for a few seconds to “clear the engine” will produce sufficient heat in the exhaust heat exchanger to warm the carb and melt ice in the carb throat.
It is also probably worth noting that the small Continentals such as what was on this J-3 are much more prone to Carb icing than their Lycoming brethren.
Thank you, you covered everything I was wondering about. Except, I wasn’t thinking that the pilot didn’t use full heat, but was concerned about not doing “clearing”.