Pilot Debrief

Arion Aircraft LLC Lightning LS-1 near Mount Pleasant, SC — 2020-04-10

Final reportERA20LA150
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Date
2020-04-10
Location
Mount Pleasant, SC, USA
Airport
LRO
Aircraft
Arion Aircraft LLC Lightning LS-1
Registration
N81DJ
Category
Airplane
Highest injury
Fatal
Fatalities
2
Phase of flight
Approach

Probable cause

The pilot's failure to maintain clearance from trees at the end of the runway due to spatial disorientation during initial climb in dark night conditions. Also causal was the flight instructor’s inadequate monitoring, which did not identify and prevent the descent and subsequent collision with trees.

NTSB narrative

The student pilot and flight instructor flew to a nearby airport where they planned to practice touch-and-go landings at night. Flight track data showed that the airplane entered a descending left turn on final approach to the runway at the destination airport. A witness reported hearing a possible airplane accident and the wreckage was subsequently located in trees bordering the south airport security fence. The wreckage path was about 250 ft long and oriented heading away from, and slightly left of the runway departure end centerline; the wreckage was heavily fragmented, consistent with a high-energy impact. A postaccident examination of the flight controls and engine did not reveal any evidence of preimpact anomalies that would have precluded normal operation. At the time of the accident, the weather was reported to be few clouds at 4,400 ft and scattered clouds at 5,500 ft. The departure end of the runway was surrounded by 75- to 100-ft-tall trees about 1,700 ft from the runway edge. Beyond the trees were some residential areas and a highway, followed by a swamp, inlet bay, and the Atlantic Ocean, which was about 2 1/2 miles from the airport. Dark night conditions existed at the time of the accident; the end of civil twilight was about 45 minutes before the accident, and the moon was below the horizon and set to rise about 50 minutes after the accident occurred. Based on autopsy findings, both the student pilot and the flight instructor had moderate coronary artery disease. While cardiovascular disease will increase the risk for an acute cardiac event, there was no evidence to suggest such an event occurred. In this case, there were also two pilots who had the ability to operate the plane if one were to become incapacitated. Based on available information, it could not be definitively determined which of the two pilots was flying the airplane at the time of the accident; however it is most likely that the student pilot, who had recently purchased the airplane, was flying with the flight instructor monitoring the flight. The circumstances of this accident are consistent with the pilot experiencing spatial disorientation, and most likely a somatogravic illusion. During the transition from the landing to the takeoff, the pilot may have interpreted acceleration cues accompanying the takeoff and initial climb as an indication that the airplane was in an abnormally high nose-up pitch attitude. Pilots experiencing this illusion make control inputs to reduce pitch, which can increase acceleration and exacerbate the illusion, leading to a failure to climb or inadvertent descent into terrain. The dark night conditions and limited cultural lighting along the flightpath would have made it difficult for the pilot to recognize that the airplane was not climbing after takeoff using external cues; the pilot likely perceived that the nose of the airplane was pitching up due to the forward linear acceleration, which caused him to push the control yoke forward. The airplane subsequently impacted the trees at high speed off the end of the runway.

Analysis

Primary failure mode
Spatial disorientation
First missed decision gate
Pilot could have opted to delay descent until visual references were available.

NTSB coding

Evidence available

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

Docket documents12

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