ERA23LA286

NTSB accident investigation · Grumman American Avn. AA5A · Redstone Arsenal, AL · July 4, 2023

Accident · No injuriesClass 3 · LimitedFinal report
Date
July 4, 2023, 14:07 local (19:07 UTC)
Place
Redstone Arsenal, AL
Injuries
2 uninjured
Damage
Substantial damage
Phase of flight
Enroute
Aircraft
N26387Grumman American Avn. AA5A
Defining event
Enroute: Powerplant sys/comp malf/fail
Weather
Visual (VMC) · Day
Status
Completed
Report
Approved by Office Director
Investigation class
Class 3
NTSB office
Eastern Region Aviation
Parties
FAA/FSDO
FAA report
20230704012019A
Case key
192517

From the NTSB’s public API. By law, NTSB reports can’t be used as evidence in lawsuits over the accident.

On this page

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.

Findings · 1

NTSB’s coded findings. Those marked are part of the probable cause; the rest are factors or other findings. Under each, the cases with the same finding.

Engine controls: power leverAircraft › Aircraft power plant · FailureGrumman American Avn. AA-5A: 1 caseAll aircraft: 95 casesProbable cause

Sequence of events

The events NTSB coded, in order, by phase of flight. The defining event is the one that best describes the accident. Under each, the cases with the same event anywhere in their sequence.

Analysis

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.

Factual narrative

On July 4, 2023, about 1407 central daylight time, a Grumman American Aviation AA-5A, N26387, was substantially damaged when it was involved in an accident near Redstone Arsenal, Alabama. The private pilot and pilot-rated passenger were not injured. The airplane was operated as a Title 14 Code of Federal Regulations Part 91 personal flight. The pilot stated that earlier that day he departed from the airplane’s home base, flew to Huntsville International Airport, Huntsville, Alabama, performed a RNAV approach, and then climbed to 3,500 ft mean sea level. While at that altitude en route to Guntersville Municipal Airport – Joe Starnes Field, Guntersville, Alabama, and while adjusting the engine power settings, the engine power decreased. He further described that the engine power was at high idle and would not respond to throttle control inputs. At that time, he declared an emergency and descended at slightly above best glide airspeed in an attempt to land at Redstone Arsenal, which he believed was the nearest airfield. When it was apparent that the airplane would be unable to reach the runway, he selected a nearby field with a paved road. After landing on the road, he applied maximum braking; however, the left wing impacted a metal pole, resulting in damage to the leading edge of the wing measuring 39 inches; the total wingspan was 31 ft 6 inches. Postaccident inspection of the engine compartment by an FAA inspector 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. A review of the maintenance records revealed the throttle cable was replaced at the airplane’s last annual inspection, which was completed on November 13, 2022. The airplane had been operated for about 15 hours since the annual inspection was completed.

Aircraft

Registration
N26387
Reported as
Grumman American Avn. AA5A (NO SERIES)
Category
Airplane
Serial number
AA5A0555
Built
1978
Airframe hours
3,902
Engine
Lycoming IO-360-C1C6, 200 horsepower, reciprocating
Damage
Substantial damage
Flight
Personal · Part 91
Airworthiness certificate
Standard, Normal; Standard, Utility
Last inspection
Annual · November 13, 2022 · 15 hours before
Departed
M38 · Hazel Green, AL
Equipment
Electronic multifunction display, Auto-pilot, Electronic primary flight display, ADS-B, Onboard weather

Matched to the registry by N-number and the event date; the registry’s history has gaps, so older matches can be wrong. Compare the reported make and model.

Flight crew · 2

As NTSB recorded them. NTSB leaves out names.

Role
Pilot
Age
51
Injuries
None
Certificate
Private
Airplane ratings
Single-engine land
Instrument ratings
Airplane
Medical
BasicMed, Without waivers/limitations
Last flight review
January 22, 2022
Seat
Left
Restraint
3-point
Flight hours
434 total · 204 in this make and model · 342 as pilot in command · 4 in the last 90 days · 3 in the last 30 days
Role
Pilot-rated passenger
Age
56
Injuries
None
Certificates
Commercial, Flight instructor
Airplane ratings
Single-engine land, Multi-engine land
Instrument ratings
Airplane
Medical
BasicMed, With waivers/limitations
Last flight review
June 10, 2023
Seat
Right
Restraint
3-point
Flight hours
3,900 total

Weather

Conditions
Visual (VMC) · Day
Wind
190° at 4 knots
Visibility
10 statute miles
Lowest ceiling
25,000 ft broken
Temperature
82 °F, dew point 72 °F
Altimeter
30.06 inHg
Observed at
KHSV, 6 nm away
METAR
METAR KHSV 041853Z 19004KT 10SM FEW016 SCT160 BKN250 28/22 A3006 RMK AO2 SLP170 T02780222 $=

Docket · 6

The files NTSB released with the investigation on February 5, 2025, on NTSB’s docket system: statements, records, photos and specialists’ reports. 8.9 MB in all.

FAA reports on this event · 1

The FAA’s own accident and incident reports, matched to the aircraft by N-number and date.