Pilot Debrief

Zenair CH601 near Maricopa, AZ — 2020-06-10

Final reportWPR20LA177
Sign in to save
Date
2020-06-10
Location
Maricopa, AZ, USA
Airport
A39
Aircraft
Zenair CH601
Registration
N6402X
Category
Airplane
Highest injury
Fatal
Fatalities
1
Phase of flight
Approach

Probable cause

The pilot’s loss of situational awareness and descent below pattern altitude during the landing approach, which resulted in collision with terrain at night.

NTSB narrative

The pilot departed from his home airport for a night flight to an airport he had flown to in the past. The flight was in trail with another airplane as they approached the airport from the north. Flight track data indicated that the accident airplane overflew the airport midfield about 300 ft below the traffic pattern altitude. The flight progressed well beyond the airport environment and descended to about 600 ft below the traffic pattern altitude. As the airplane began what appeared to be an extended base turn to the southeast, about 2 miles from the runway threshold, it struck an isolated and unlit hill just below its summit. Examination of the wreckage did not reveal any mechanical anomalies with the airplane or engine, and damage signatures to the propeller indicated that the engine was producing power at impact. Based on autopsy findings, the pilot had mild-to-moderate atherosclerosis in his coronary arteries. While the atherosclerosis placed the pilot at some increased risk for an acute cardiac event, there was no evidence to suggest such an event occurred and, given the pilot was communicating with air traffic control and the other airplane right up until the accident, the pilot’s cardiovascular disease was not a factor. Given the operational issued of the accident, the ethanol concentrations identified in liver tissue were from sources other than ingestion. At the time of the accident, the sun had set, but there was still light on the horizon, toward the direction the airplane was heading prior to turning toward the airport. The light conditions would have provided a challenging perceptual environment for the pilot as he looked toward the unlit terrain and peak. It was likely that the pilot’s visual attention was directed toward the airport at that time, while he monitored the other airplane and positioned himself for landing. Both factors would have impeded the pilot’s visual identification of the terrain. Further, the limited cultural lighting in the vicinity of the airport would provide few cues from which the pilot could reliably estimate distance while maneuvering. The reason for the pilot’s nonstandard flight track and flight below pattern altitude is unknown, but it is indicative of the pilot losing situational awareness as he followed the other airplane in the traffic pattern and prepared for landing over unlit and unpopulated terrain.

Analysis

Primary failure mode
Controlled flight into terrain
First missed decision gate
Pilot could have chosen to avoid flying at night in unlit terrain.

NTSB coding

Evidence available

  • Video
  • ADS-B / radar
  • Photos
  • 11 docket documents
View NTSB final reportView NTSB docket

Docket documents11

Related mishaps