FlightFollowerBeech A36 N19MT — Dead Cylinder, Oil Pressure Loss and Engine Failure
The Flight & Context
On January 19, 2023, a Beech A36, N19MT, was conducting an IFR personal flight from New York toward Ohio when the aircraft developed degraded climb performance. The pilot and one passenger were aboard. The NTSB investigation found that the eventual loss of engine power resulted from a failure of the No. 4 piston and the subsequent loss of engine oil.
The Engine Warning Signs
Recorded engine data showed the No. 4 cylinder-head temperature exceeding its highest allowed value shortly after takeoff. The temperature later fell in a pattern consistent with the cylinder no longer firing correctly. The flight continued while the engine problem developed.
The Emergency Sequence
At about 17:18:30, the pilot reported a dead cylinder and requested to proceed toward Westchester County Airport. ATC issued a 340-degree heading, but the aircraft did not immediately follow it. At 17:20:11, engine data showed oil pressure falling below the specified minimum and continuing toward zero.
The pilot eventually turned toward the assigned heading and later declared an emergency, reporting that the oil pressure was dropping. A subsequent uncommanded right turn increased the distance and flight time to the intended runway. The controller issued another vector. The engine then lost all power, and the aircraft descended toward the airport before striking trees and terrain less than one mile from the runway threshold.
What the Investigation Found
The NTSB found damage to the No. 4 piston consistent with pre-ignition or detonation. The damage pressurized the crankcase, pushed oil out through the breather system and depleted the oil supply, ultimately causing catastrophic internal engine failure. Investigators could not determine the underlying reason for the pre-ignition/detonation.
Probable Cause
The NTSB determined that the probable cause was pre-ignition/detonation damage to the No. 4 piston for reasons that could not be determined, which caused crankcase pressurization, oil exhaustion and catastrophic internal engine failure.
Key Takeaways / Lessons Learned
The case demonstrates why engine trend information can matter before a complete power loss. A rising cylinder temperature, degraded climb performance and a reported dead cylinder were separate warning signs of a deteriorating engine condition. Once the emergency developed, minimizing delay and preserving the most direct path to a suitable runway became critical.
On January 19, 2023, about 1729 EST, a Beech A36, N19MT, was substantially damaged when it was involved in an accident near North Castle, New York. The private pilot and one passenger were fatally injured. The airplane was operated as a Title 14 Code of Federal Regulations Part 91 personal flight.
About 18 minutes after takeoff, while on an instrument flight rules (IFR) flight, the pilot requested a lower altitude, advising the controller that the airplane’s climb performance was degraded. As the flight continued the pilot recognized a “dead cylinder” and requested a heading to a nearby airport. The controller vectored the flight to the airport, but the pilot delayed turning onto the vectored heading for over 2 minutes.
When the flight was about 6 nautical miles from the airport the pilot declared an emergency and advised the controller that the oil pressure was dropping. After turning onto the vectored heading, the airplane began a right turn that was not directed by the controller or announced by the pilot. The controller informed the pilot to level the wings and maintain 5,000 ft msl.
The change in the airplane’s heading resulted in the controller providing a new vector, which increased the distance and flight time to the intended runway. Recorded data showed the engine then lost all power. The airplane continued to descend and subsequently collided with trees and the ground less than 1 mile from the intended runway threshold.
According to recorded data, shortly after takeoff, when the flight was about 1 nautical mile from the departure end of the runway, the No. 4 cylinder head temperature (CHT) value exceeded the highest allowed value. The flight continued while the No.
4 CHT continued to increase. The CHT for that cylinder then began to decrease, consistent with non-firing of the fuel air mixture, and the flight continued. Postaccident examination of the engine revealed damage to the top and sides of the No.
4 piston that were likely the result of pre-ignition/detonation that pressurized the crankcase, pushing oil out of the breather assembly and depleting the oil supply. This ultimately resulted in oil exhaustion and subsequent catastrophic internal engine failure. Both spark plugs of the No.
4 cylinder had extensive deposits and one had a separated section of core nose insulator while the other only had a cracked core nose insulator, though it could not be determined from the available evidence if those conditions existed before or were the result of preignition/detonation. Causes for detonation include improper ignition timing, high inlet air temperature, engine overheating, carbon build-up or oil in the combustion chamber, an issue with the fuel octane, or a lean fuel-to-air mixture. Although the magneto-to-engine timing could not be determined postaccident, there were no postaccident anomalies noted with either the magneto or the ignition harness.
High inlet air temperature, engine overheating, or carbon build-up/oil in the combustion chamber were not likely or not observed. There was no report of any fuel-related issue from the facility that last fueled the accident airplane. While the position of the mixture control during the flight and the pilot’s leaning procedures were unknown, it is unlikely that the pilot would have leaned the fuel-to-air ratio to CHT exceedance as that would have been contrary to the published limitations and takeoff procedures.
Accident Facts
- Incident date
- 19 Jan 2023
- Registration
- N19MT
- Category
- Emergency, Crash, Fuel, Engine failure
- Reconstruction
- 9:35
Sources
Primary Source / Investigation Record
Primary Investigation Reference
NTSB accident number: ERA23FA113
Primary investigation report: ERA23FA113