Pilot Debrief

ALON A2 near Laramie, WY — 2015-09-11

Final reportCEN15LA407
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Date
2015-09-11
Location
Laramie, WY, USA
Aircraft
ALON A2
Registration
N6359V
Category
Airplane
Highest injury
Serious
Fatalities
0
Phase of flight
Climb

Probable cause

The pilot’s failure to use carburetor heat in cruise flight while operating in an area conducive to serious carburetor icing, which resulted in a loss of engine power and an off-airport landing. Contributing to the accident was the pilot's decision to continue flight toward rising mountainous terrain when the airplane could not maintain altitude.

NTSB narrative

The private pilot reported that, after departing and then making a slow circling climb to about 9,500 ft mean sea level (msl), the airplane was unable to climb any higher and was occasionally descending. The pilot began to fly on course toward higher terrain, and the engine suddenly began to lose power. The pilot applied carburetor heat, but engine power was not restored. The airspeed then slowed, and the airplane descended. The airplane impacted the concrete median barrier on the highway in a narrow mountain pass at an estimated terrain elevation of 7,980 ft msl and then came to rest upright. There was a fuel spill at the scene but no postimpact fire, and the injured pilot was able to exit the airplane without assistance. A postaccident examination of the airplane and engine found no preaccident mechanical malfunctions or failures that would have precluded normal operation. The pilot reported that the airplane had been recently fitted with a 4-point inertial reel shoulder harness system and that it is likely that his use of that shoulder harness system prevented him from sustaining a more serious injury. The weather conditions about the time of the accident were conducive to the accumulation of serious carburetor icing at all power settings. Federal Aviation Administration guidance states that, when conditions are conductive to carburetor icing, the pilot should immediately apply carburetor heat and that the heat should be left on until the pilot is certain that all of the ice has been removed. It is likely that the engine began to lose power due to carburetor ice and that the timely application of carburetor heat would have restored engine power.

Analysis

Primary failure mode
Engine power loss
First missed decision gate
Pilot could have avoided higher terrain after engine power loss.

NTSB coding

Evidence available

  • Photos
  • 7 docket documents
View NTSB final reportView NTSB docket

Docket documents7

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