Pilot Debrief

GRUMMAN AMERICAN AVN. CORP. AA5A near Redstone Arsenal, AL — 2023-07-04

Final reportERA23LA286
Sign in to save
Date
2023-07-04
Location
Redstone Arsenal, AL, USA
Aircraft
GRUMMAN AMERICAN AVN. CORP. AA5A
Registration
N26387
Category
Airplane
Highest injury
None
Fatalities
0
Phase of flight
Cruise

Probable cause

The separation of the clamp assembly securing the throttle control cable outer housing, which resulted in the pilot’s inability to control the throttle.

NTSB narrative

After takeoff the pilot performed a practice RNAV approach, then climbed to 3,500 ft mean sea level en route to another airport. While at altitude the pilot attempted to adjust the engine power settings, but the engine power “went to low power and was not responding to throttle control inputs.” He declared an emergency and after realizing that the flight was unable to reach a nearby airport, he selected a nearby field with a paved road. After landing on the road, he applied maximum braking, but the left wing impacted a metal pole, resulting in substantial damage to the leading edge of the wing. Postaccident inspection of the engine compartment revealed the throttle control cable assembly remained attached to the throttle control lever of the fuel injection servo, but the outer cable assembly was not secured in the engine compartment. Thus, movement of the throttle control in the cockpit did not result in movement of the throttle control lever. A clamp, shim, two screws, and two metal self-locking nuts that secured the outer cable assembly were not located, but a washer was found loose in the engine compartment. The throttle cable was replaced at the airplane’s last annual inspection 8 months earlier; the airplane had been operated for about 15 hours since the annual inspection. Although it is unlikely that the screws used to secure the cable would have sheared or failed, they were not located. Thus, the reason for the outer cable clamping hardware to separate could not be determined from the available evidence.

Analysis

Primary failure mode
Mechanical failure
First missed decision gate
Pilot could have checked throttle cable security before flight.

NTSB coding

Evidence available

  • 6 docket documents
View NTSB final reportView NTSB docket

Docket documents6

Related mishaps