Before departure for the flight, the private pilot and owner of the Cessna 172 conducted the preflight and run-up and noted the airplane was operating normally. During takeoff, he rotated about 70 knots and the climb out was normal. About 300 feet above ground level, the engine suddenly lost power and shook violently.
The pilot scanned for potential emergency landing areas and decided to attempt to land in a soybean field near Natchitoches, La., that was about 135° degrees to his left.
The airplane overflew the soybean field and hit a line of trees at the end of the field, resulting in one fatality.
The post-accident examination of the engine revealed that the No. 1 cylinder exhaust valve rocker retaining stud was backed out of the cylinder head threads by about 5 threads, or about ¼ inch, and the valve rocker and pushrod were loose.
The clearance between the valve rocker and the valve stem was too great to allow the exhaust valve to open as the engine rotated.
The last engine overhaul was conducted on May 26, 1990, and had 958.1 hours of operation since the overhaul.
The engine manufacturer recommends that engines that have not accumulated the recommended hourly time between overhauls be overhauled during the 12th year after the last overhaul; it had been over 24 years since the last overhaul.
A post-accident examination also revealed that the flaps were in the up position and that the flap handle, flap indicator, and the flap actuator were in the up position.
Had the pilot lowered the flaps, flown S-turns, or slipped the airplane, he most likely would have been able to land the airplane in the soybean field, avoiding impact with trees at the end of the field.
The NTSB determined the probable cause as the partial loss of engine power due to the exhaust valve rocker retaining stud backing out of the cylinder head, which resulted in the exhaust valve being stuck in the closed position. Contributing to the accident was the pilot’s failure to configure the airplane and fly it in a manner that would allow him to make the emergency landing in the field rather than overfly it, and the pilot’s failure to have the engine overhauled according to the recommended overhaul interval.
NTSB Identification: CEN14FA435
This August 2014 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.
Who among us is able to predict accurately when an engine is going to fail? NONE can do it……. thus as a PIC one must be prepared to exercise the PIC authority granted to you by the FAA………… read it again and again and again…….. FAR 91.3
One can armchair quarterback this all you want………. bottom line…….. are you prepared to make whatever decision necessary to ensure you die of old age and not in an aircraft? Are you a subject matter expert on the aircraft you are flying…. not the one you flew yesterday… the one your are flying today….. are you prepared to sacrifice the aircraft so you may live? If you are not… then why do you purchase aircraft insurance?
AND, it does not matter if you are at 10,000 ft agl or 300 agl…. the PIC must do whatever is necessary (yes, a slip, a quick S turn is doable and appropriate)…. but most PIC will not because they are not prepared to make those decisions………….. WHY is the question…… when does gravity ever stop working on planet earth? When do the laws of physics stop working?……… you are the PIC, I suggest you be one… but it takes time, dedication, discipline and knowledge to make sure each, and everytime you are in command of an aircraft that you are able and willing to make split second decisions to save your life. You are not play-acting……… the aircraft will always obey the laws of physics !!!!!!!!!!!!!!!!!!!!!!!
The cause of engine failure is immaterial. An emergency off-field landing requires the pilot to know how to fly power off to a designated area. Since the early “70’s when the FAA decided idle power landing approaches were contributing to base/final turn stalls, there has been no requirement for private pilots to demonstrate proficiency in idle power landings. The FAA statistics from 2001 showed 75% off field landings touched down midfield or beyond the chosen area. 50% of the fatalities were from overrunning the area.
That would not have caused a sudden lose of all power It would have ran rough but should have been able to return to airport so i presume that there was something else wrong also
I find it difficult to believe the stud all of a sudden came loose and backed out. This probably was something coming on for a while, which should have been obvious long time ago. The engine not being overhauled within the 12 years is really immaterial. Had the valve covers been off? Any inspection previously? Why did it back out and would the stud have backed out if under 12 years?
If everything on the engine checked out, why overhaul?
It’s easy to point to something like this and say he should have overhauled the engine 12 years prior, however it may not have made a difference. The question is why did the stud back out? Was the engine run hot? Why didn’t the pilot or AP pick up on the problem sooner? Had to be down on power.
S turns? I don’t think so, at 300 feet it gives little time to troubleshoot, check fuel, gauges, make a turn, find the field etc. He may have made the field and then just floated? What were the winds? Don’t know. I’m not blaming the pilot.
I agree with observations that the 12 year ‘TBO’ issue expressed by the author of the NTSB Probable Cause statement is bogus. I also agree that the IA who inspected the engine at annual was guilty of missing or misinterpreting the symptoms of this soon-to-fail engine. While we can fault the pilot for being oblivious to developing symptoms, the IA and any A&P who worked on the plane were the “experts”. FWIW, the NTSB Factual report says a series of SB’s were published for rocker arm issues. HOWEVER, the SN of this aircraft and engine were not included for two listed, and the third was only effective at overhaul. Why then, was this extraneous and irrelevant information even mentioned? Does the NTSB believe aircraft owners should comply with SB that aren’t included in the affected population of aircraft, appliances, and engines??? Was it just cover for Lycoming and the FAA since if this was a really serious problem it warranted an AD (which was issued… but excluded this engine)??? So much for the bogus over TBO issue. Regardless, SB are not required of Part 91 operations, which this was.
I disagree, however, that at 300 feet “S” turns and aggressive slips with partial power available (or no power) wouldn’t have been both timely and effective. Engine failure at that altitude leaves little time for “trouble shooting” beyond checking carb heat, mixture, throttle and selecting a landing site. IMHO aggressive slips and “S” turns would be an either or choice. Again, IMHO, the odds of uncoordinated turns would be high. That, in combination with flaps down partially masking airflow over the tail would increase potential for low altitude, unsurvivable spin. FWIW, the NTSB Docket is not available at this time, so it’s not possible to determine whether the 80 year old private pilot was proficient, or the extent of his recent flight experience. Given his flawed response to this emergency it appears his proficiency and decision making under stress were subpar.
You blame the IA that did the last annual, but the valve adjustment would have been a recent event – probably done before this last flight.
Aircraft owners need an annual inspection, but there is no telling what an owner, or a hack mechanic, might do after the IA has completed his inspection.
“Fly ‘S’ turns” from 300 feet AGL with a dead engine??
Full flaps and slipping would likely have been more than enough to get it down. S-turning from that altitude would not have been a wise choice.
woulda, coulda, shoulda, do this, do that, and all will be well. Maybe the pilot did not have enough time to do everything that might have made for a safe landing. Panic might have happened and caused valuable seconds to be wasted. In a tough situation a lot of people develop tunnel vision and the brain does not work so well. I had a similar situation, burnt valve, but I was 1000 agl and was able to get back to the airport alright. It is always easy to blame the pilot.