Saturday, March 30, 2019

Loss of Engine Power (Partial): Grumman G-164 Ag-Cat, N6637, accident occurred April 27, 2018 in Garwood, Colorado County, Texas

The National Transportation Safety Board did not travel to the scene of this accident.

Additional Participating Entity: 

Federal Aviation Administration / Flight Standards District Office; Houston, Texas

Aviation Accident Final Report - National Transportation Safety Board: https://app.ntsb.gov/pdf 


Investigation Docket - National Transportation Safety Board: https://dms.ntsb.gov/pubdms 


Aviation Accident Data Summary - National Transportation Safety Board: https://app.ntsb.gov/pdf  

http://registry.faa.gov/N6637


Location: Garwood, TX
Accident Number: CEN18LA152
Date & Time: 04/27/2018, 1800 CDT
Registration: N6637
Aircraft: GRUMMAN G 164A
Aircraft Damage: Substantial
Defining Event: Loss of engine power (partial)
Injuries: 1 None
Flight Conducted Under: Part 137: Agricultural 

Analysis 

The commercial pilot was departing on an agricultural application flight when the engine experienced a partial loss of power shortly after takeoff. The pilot released part of the load of fertilizer and attempted to land in a nearby field. The airplane contacted a levee during the landing, which separated the landing gear. The airplane became airborne again, then settled back onto the ground and subsequently nosed over. The reported weather conditions were conducive to serious carburetor icing at glide power; however, the airplane was operating at a high power setting for takeoff. Therefore, it is unlikely that carburetor icing was present. A postaccident examination of the engine did not reveal any mechanical malfunctions or anomalies and the reason for the partial loss of power could not be determined.

Probable Cause and Findings

The National Transportation Safety Board determines the probable cause(s) of this accident to be:
A partial loss of engine power for reasons that could not be determined because postaccident examination of the engine did not reveal any anomalies that would have precluded normal operation.

Findings

Not determined
Not determined - Unknown/Not determined (Cause)


Factual Information

On April 27, 2018, at 1800 central daylight time, a Grumman G-164A airplane, nosed over during an off airport forced landing in Garwood, Texas. The pilot was not injured. The airplane was substantially damaged. The airplane was registered to and operated by Aero Ag Services Inc., as a Title 14 Code of Federal Regulations Part 137 aerial application flight. Day visual meteorological conditions prevailed. The flight was not operated on flight plan. The local flight was originating from a private airstrip in Garwood, Texas, when the accident occurred.

The pilot reported that he was taking off with a full load of fertilizer on the 28TH flight of the day when the accident occurred. He stated the ground run and lift off were normal. After lifting off, he began a turn and reduced the engine power to 32 inches of manifold pressure. He then felt a "slight shudder" and an additional reduction in engine power with no sputtering or backfiring. Although the manifold pressure still indicated 32 inches of manifold pressure and the propeller was at full rpm, the pilot decided to return to the airstrip. As he turned, the pilot perceived that the engine was not producing power, so he leveled the wings, lowered the nose, and dumped some of the fertilizer load. The airplane contacted a levee during the forced landing which separated the landing gear and the airplane becoming airborne. The airplane touched down a second time and nosed over.

A postaccident examination of the engine was conducted on September 12, 2018, at Air Salvage of Dallas, Lancaster, Texas. One propeller blade was bent rearward about 70° and the other was slightly bent rearward. The carburetor was broken off the engine. Both magnetos produced spark when rotated by hand. Engine continuity was established, and compression was achieved on all cylinders except for the No. 5 cylinder that sustained impact damage. The spark plugs were removed. All the plugs were slightly dark in color with normal wear signatures. The blower impeller was visually examined and appeared normal. The impeller appeared to have excessive backlash, about 0.750 inches, but there was no end play and no signs of contact between the impeller and the case. No metal was detected in the oil sump or inlet screen. The air box and air filter were clear of debris. The carburetor heat door was wired in the open/off position. The examination of the engine did not reveal any anomalies that would have precluded normal operation.

The temperature and dewpoint recorded at the Wharton Regional Airport (ARM), Wharton, Texas, located 23 miles southeast of the accident site, at 1815 were 77°F and 48°F respectively. According to the Federal Aviation Administration SAIB CE-09-35 Carburetor Icing Probability Chart those conditions were favorable for serious carburetor icing at glide power.

History of Flight

Initial climb
Loss of engine power (partial) (Defining event)

Landing
Collision with terr/obj (non-CFIT)

Landing-flare/touchdown
Landing gear collapse
Nose over/nose down

Pilot Information

Certificate: Commercial
Age: 29, Male
Airplane Rating(s): Single-engine Land
Seat Occupied: Center
Other Aircraft Rating(s): None
Restraint Used: 4-point
Instrument Rating(s): None
Second Pilot Present: No
Instructor Rating(s): None
Toxicology Performed: No
Medical Certification: Class 2 Without Waivers/Limitations
Last FAA Medical Exam: 12/28/2017
Occupational Pilot: Yes
Last Flight Review or Equivalent: 01/05/2017
Flight Time:  2140 hours (Total, all aircraft), 1125 hours (Total, this make and model), 2115 hours (Pilot In Command, all aircraft), 240 hours (Last 90 days, all aircraft), 40 hours (Last 30 days, all aircraft), 6 hours (Last 24 hours, all aircraft)

Aircraft and Owner/Operator Information

Aircraft Make: GRUMMAN
Registration: N6637
Model/Series: G 164A
Aircraft Category: Airplane
Year of Manufacture: 1970
Amateur Built: No
Airworthiness Certificate: Restricted
Serial Number: 766
Landing Gear Type: Tailwheel
Seats: 1
Date/Type of Last Inspection: 02/28/2018, Annual
Certified Max Gross Wt.: 6000 lbs
Time Since Last Inspection: 20 Hours
Engines: 1 Reciprocating
Airframe Total Time: 17000 Hours
Engine Manufacturer: Pratt & Whitney
ELT: Not installed
Engine Model/Series: R-1340-AN1
Registered Owner: AERO AG SERVICES INC
Rated Power: 600 hp
Operator: AERO AG SERVICES INC
Operating Certificate(s) Held: Agricultural Aircraft (137) 

Meteorological Information and Flight Plan

Conditions at Accident Site: Visual Conditions
Condition of Light: Day
Observation Facility, Elevation: KARM, 100 ft msl
Distance from Accident Site: 23 Nautical Miles
Observation Time: 1815 CDT
Direction from Accident Site: 118°
Lowest Cloud Condition: Clear
Visibility: 10 Miles
Lowest Ceiling: None
Visibility (RVR):
Wind Speed/Gusts: 7 knots /
Turbulence Type Forecast/Actual: /
Wind Direction: 10°
Turbulence Severity Forecast/Actual: /
Altimeter Setting: 30.01 inches Hg
Temperature/Dew Point: 25°C / 9°C
Precipitation and Obscuration: No Obscuration; No Precipitation
Departure Point: Garwood, TX (PVT)
Type of Flight Plan Filed: None
Destination: Garwood, TX (PVT)
Type of Clearance: None
Departure Time:  CDT
Type of Airspace: Class G

Airport Information

Airport: Private (PVT)
Runway Surface Type: Dirt
Airport Elevation: 178 ft
Runway Surface Condition: Rough
Runway Used: N/A
IFR Approach: None
Runway Length/Width:  
VFR Approach/Landing: Forced Landing 

Wreckage and Impact Information

Crew Injuries: 1 None
Aircraft Damage: Substantial
Passenger Injuries: N/A
Aircraft Fire: None
Ground Injuries: N/A
Aircraft Explosion: None
Total Injuries: 1 None
Latitude, Longitude: 29.444722, -96.399167

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