Accident Grumman G-164A Ag-Cat N7849, Saturday 29 June 2024
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Date:Saturday 29 June 2024
Time:18:40 LT
Type:Silhouette image of generic G164 model; specific model in this crash may look slightly different    
Grumman G-164A Ag-Cat
Owner/operator:Private
Registration: N7849
MSN: 797
Year of manufacture:1971
Total airframe hrs:12212 hours
Engine model:Honeywell TPE 331-1-151A
Fatalities:Fatalities: 0 / Occupants: 1
Other fatalities:0
Aircraft damage: Substantial
Category:Accident
Location:Toccoa Airport-RG Letourneau Field (TOC/KTOC), Toccoa, GA -   United States of America
Phase: Landing
Nature:Ferry/positioning
Departure airport:Toccoa, GA
Destination airport:Walnut Ridge Airport, AR (ARG/KARG)
Investigating agency: NTSB
Confidence Rating: Accident investigation report completed and information captured
Narrative:
The pilot of the turbo propeller-powered agricultural airplane reported that, during takeoff for a cross-county flight, the engine rpm did not reach 100% but he continued the flight. Shortly after takeoff, the engine appeared to surge and the pilot decided to return to the departure airport. As he approached the airport, the surging worsened and, after touchdown, the engine power started to increase. He tried to shut down the engine, but the power continued to increase. He applied heavy braking to slow the airplane; the left brake then locked, and the airplane departed the runway and the airplane's wings were substantially damaged.
Postaccident examination of the engine revealed damage indicative of an engine that was rotating and operating at the time of impact; no pre-existing condition was found that would have prevented normal engine operation or control. The engine manufacturer issued a Pilot Advisory Letter more than 10 years before the accident addressing the issue of engine oscillations. The letter noted:
When performing a takeoff, pilots normally advance the power lever(s) to a takeoff value as specified in the POH/AFM and as indicated on the torque (or equivalent) gauge. If a takeoff is attempted with the Engine Speed Control(s) in any position other than full forward, resulting in the engine not achieving 100-101% RPM, the engine(s) may very well achieve the desired indicated torque; however, the engine(s) will actually develop a reduced level of horsepower. A reduced level of horsepower will result in the degradation of aircraft performance.
The letter added that, “One and possibly two adverse effects can result if a takeoff is attempted with the Engine Speed Control(s) in any position other than full forward. They are reduced power output from the engine(s) and the possibility of accompanying engine oscillations.'
Since the previous 22 hours of flying did not demonstrate this type of engine behavior, postaccident examination of the engine found no issues that would have prevented normal operation, and the pilot reported both not achieving 100% speed as well as engine oscillations during and after takeoff, the pilot likely did not advance the engine speed control fully forward during takeoff.

Probable Cause: The pilot's failure to set the engine speed control fully forward during takeoff, resulting in an engine surge and subsequent loss of control during landing.

Accident investigation:
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Investigating agency: NTSB
Report number: ERA24LA286
Status: Investigation completed
Duration: 1 year and 2 months
Download report: Final report

Sources:

NTSB ERA24LA286

History of this aircraft

Other occurrences involving this aircraft

17 January 1997 EC-ECP Fuentes de Andalucía (Sevilla) w/o

Location

Revision history:

Date/timeContributorUpdates
02-Jul-2024 13:07 Captain Adam Added
11-Jul-2024 21:59 Captain Adam Updated [Time, Operator, Location, Nature, Departure airport, Destination airport, Narrative, Category, Accident report, ]
01-Oct-2025 09:38 ASN Update Bot Updated [Time, Departure airport, Source, Narrative, Accident report, ]

Corrections or additions? ... Edit this accident description

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