Aviat A-1C-200 N280TB

Summary

On 15 October 2015 at about 23:07 local time, a Aviat A-1C-200 registered N280TB was involved in an accident near Swan Valley, Idaho, United States. 2 people were on board and one died, one was seriously injured. The aircraft was substantially damaged. The NTSB has published a probable cause for this accident; it is quoted in full below.

Date

15 October 2015 at 23:07

Classification

Accident

Location

Swan Valley, Idaho, United States

Coordinates

43.2233, -111.0614

Aircraft

Aviat A-1C-200

Registration

N280TB

Category

Airplane

Year built

2015

Engines

1

Operator

Not recorded

Operating rule

Part 91: General Aviation

Purpose of flight

Personal

Phase of flight

Not recorded

Route

Alpine → Alpine

Aircraft damage

Substantial

Weather

VMC

Light

Day

NTSB number

WPR16FA013

1 person died.

The pilot's failure to maintain airspeed while maneuvering in high density altitude conditions over mountainous terrain, which resulted in the airplane exceeding its critical angle of attack and experiencing an aerodynamic stall.

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

Read the full NTSB narrative

The airline transport pilot, and one passenger, were conducting a formation pleasure/sightseeing flight with another airplane in mountainous terrain. The pilot of the second airplane, who was flying in trail behind the accident airplane, stated that the two airplanes flew into a canyon area. As they approached a ridgeline, the second pilot performed a 360° climbing turn to gain altitude prior to crossing the ridgeline. After he completed his turn, he noticed a dust cloud on the ground ahead of him, and realized that the lead airplane had impacted terrain. Postaccident examination of the airplane revealed no evidence of mechanical malfunctions of failures that would have precluded normal operation. The density altitude about the time of the accident was over 10,990 ft. Data recovered from the airplane's avionics system indicated that the engine was producing full power throughout the 24-minute flight. Before impact, the airplane's airspeed decreased to between 48 and 50 knots. The airplane's published stall speed was between 46 and 55 knots, depending on the airplane's configuration. Signatures at the accident site and the damage to the airplane indicated a near-vertical impact, consistent with an aerodynamic stall. The passenger reported that, before impact, the airplane was in a turn, and that she heard a beeping sound, consistent with activation of the aural stall warning. Despite the fact that the airplane's engine was producing full power, the high density altitude conditions would have degraded the engine's performance and the airplane's ability to climb. It is likely that, as the pilot was maneuvering the airplane in an attempt to climb over the rising terrain, he allowed the airspeed to decay and the airplane exceeded its critical angle of attack and subsequently experienced an aerodynamic stall.

Quoted verbatim from the NTSB record.