Grumman AA1 N6216L

Summary

On 1 August 2017 at about 20:00 local time, a Grumman AA1 registered N6216L was involved in an accident near Phoenix, Arizona, United States. 2 people were on board and 2 were seriously injured. The aircraft was substantially damaged. The NTSB has published a probable cause for this accident; it is quoted in full below.

Date

1 August 2017 at 20:00

Classification

Accident

Location

Phoenix, Arizona, United States

Nearest airport

Phoenix Deer Valley (DVT)

Coordinates

33.6867, -112.0997

Aircraft

Grumman AA1

Registration

N6216L

Category

Airplane

Year built

1972

Engines

1

Operator

Not recorded

Operating rule

Part 91: General Aviation

Purpose of flight

Personal

Phase of flight

Not recorded

Route

Phoenix → Sedona

Aircraft damage

Substantial

Weather

VMC

Light

Day

NTSB number

WPR17LA175

2 people were seriously injured.

The partial loss of engine power during initial climb due to the No. 3 cylinder exhaust valve becoming stuck open due to deposit buildup in the exhaust valve stem and guide and the pilot’s exceedance of the airplane’s critical angle of attack while attempting to turn back to the airport, which resulted in an aerodynamic stall. 

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

Read the full NTSB narrative

Shortly after the private pilot took off for the local flight, about 200 to 300 ft above ground level, the engine experienced a partial loss of power. The airport was bordered on the south, west, and north by buildings, and there were high-traffic arterial roads on both the west and south sides of the airport; the pilot turned the airplane back toward the departure runway to make an emergency landing to the east. During the turn, the pilot exceeded the airplane's critical angle of attack, which resulted in an aerodynamic stall. The pilot was unable to regain control, and the airplane pitched nose down and subsequently impacted terrain and then collided with an airport perimeter fence and a tree before coming to rest. Postaccident examination of the propeller blades revealed chordwise striations across the cambered surface, torsional twisting, and trailing edge "S" bending, consistent with the engine producing power at the time of impact. The engine teardown examination revealed that the No. 3 cylinder's exhaust valve was stuck open, which would have degraded the engine power. Further, the exhaust valve stem and guide exhibited heavy combustion deposits, which likely led to the valve becoming stuck. No preaccident deficiencies were found with the cylinder.

Quoted verbatim from the NTSB record.