Cirrus SR22 N969JM

Summary

On 22 November 2019 at about 19:38 local time, a Cirrus SR22 registered N969JM was involved in an accident near Tyler, Texas, United States. 3 people were on board and 2 were seriously injured. The aircraft was substantially damaged. The NTSB has published a probable cause for this accident; it is quoted in full below.

Date

22 November 2019 at 19:38

Classification

Accident

Location

Tyler, Texas, United States

Coordinates

32.4897, -95.4819

Aircraft

Cirrus SR22

Registration

N969JM

Category

Airplane

Year built

2014

Engines

1

Operator

Not recorded

Operating rule

Part 91: General Aviation

Purpose of flight

Personal

Phase of flight

Not recorded

Route

Terrell → Gladewater

Aircraft damage

Substantial

Weather

IMC

Light

Day

NTSB number

CEN20LA020

2 people were seriously injured.

A total loss of engine power as a result of detonation due to a combination of improper magneto to engine timing and a rich fuel mixture.

Quoted verbatim from the NTSB record. This site does not paraphrase or interpret it.

Read the full NTSB narrative

According to the pilot, about 2 minutes after leveling off at a cruise altitude of 3,000 ft above mean sea level (msl), the engine shook and vibrated. He switched his multifunction display (MFD) to the engine parameter page and all engine indications appeared normal. About 2 minutes later, the indication of the No. 5 engine cylinder turned from green to red. He then reported the engine problem to air traffic control and announced his intentions to divert to an alternate airport. Unable to maintain altitude he began a descent. Shortly thereafter, the engine appeared to operate normally, and he was able to climb about 200 ft per minute before the shaking returned. The airplane descended out of the clouds about 1,200 ft msl, and the pilot deployed the airplane’s parachute system. The airplane impacted the ground and was substantially damaged.   A postaccident examination of the engine revealed that the No. 5 piston head exhibited cleaning and damage consistent with detonation, while the No. 1 cylinder exhibited signatures consistent with the initial phase of detonation. The magneto timing on the engine measured at 27° before top center (BTC) rather than the factory specification of 24° BTC. According to the engine manufacturer, coupled with a rich mixture, this could result in detonation. When asked to describe the engine leaning procedure used, the pilot stated that he would lean the mixture to the blue line on the MFD. According to the airframe manufacturer, the Lean Assist blue line does not take into account engine timing. It is likely that the incorrect engine timing, when combined with a mixture setting that was too rich for the engine condition, resulted in detonation. Investigators did not establish the last time the engine timing was adjusted.

Quoted verbatim from the NTSB record.