# NTSB CEN18LA152: Grumman G 164A, N6637, Garwood, TX, April 27, 2018 - Type: NTSB accident investigation - Classification: Accident · No injuries · Limited investigation · Final report - Date: April 27, 2018, 18:00 local (23:00 UTC) - Place: Garwood, TX - Coordinates: 29.444723, -96.399169 - Nearby events: https://openairdocs.org/map.md?lat=29.4447&lon=-96.3992&mi=10 - Phase of flight: [Initial climb](https://openairdocs.org/ntsb-phases/350) (OpenAirDocs' grouping) - Defining event: [Initial climb: Loss of engine power (partial)](https://openairdocs.org/ntsb-events/342) - Highest injury: No injuries - Injuries: 1 uninjured - Status: Completed, report March 18, 2019 - Report: Approved by Office Director - NTSB office: Central Region - Parties: FAA - SAIBs cited in the narratives: [SAIB CE-09-35](https://openairdocs.org/saib/CE-09-35) (OpenAirDocs) - NTSB case key (mKey): 97131 - NTSB case page: https://web.ntsb.gov/investigations/?ntsbnumber=CEN18LA152 - NTSB report (PDF, downloads): https://data.ntsb.gov/carol-repgen/api/Aviation/ReportMain/GenerateNewestReport/97131/pdf - NTSB docket: https://data.ntsb.gov/Docket?ProjectID=97131 - Page: https://openairdocs.org/ntsb/CEN18LA152 ## Probable cause 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 NTSB's coded findings; those marked are part of the probable cause. - [Not determined](https://openairdocs.org/ntsb-findings/05000000): Not determined › Not determined · Unknown/Not determined (probable cause); cases with it: [Grumman G-164A, 7 cases](https://openairdocs.org/ntsb-findings/05000000/cases.md?model=3952704), [All aircraft, 2,247 cases](https://openairdocs.org/ntsb-findings/05000000/cases.md) ## Sequence of events The events NTSB coded, in order, by phase of flight. The defining event best describes what happened. - [Initial climb: Loss of engine power (partial)](https://openairdocs.org/ntsb-events/342) (defining event); cases with it: [Grumman G-164A, 7 cases](https://openairdocs.org/ntsb-events/342/sequence.md?model=3952704), [All aircraft, 1,858 cases](https://openairdocs.org/ntsb-events/342/sequence.md) - [Landing: Collision with terr/obj (non-CFIT) ](https://openairdocs.org/ntsb-events/470); cases with it: [Grumman G-164A, 9 cases](https://openairdocs.org/ntsb-events/470/sequence.md?model=3952704), [All aircraft, 10,189 cases](https://openairdocs.org/ntsb-events/470/sequence.md) - [Landing-flare/touchdown: Landing gear collapse](https://openairdocs.org/ntsb-events/094); cases with it: [Grumman G-164A, 4 cases](https://openairdocs.org/ntsb-events/094/sequence.md?model=3952704), [All aircraft, 1,787 cases](https://openairdocs.org/ntsb-events/094/sequence.md) - [Landing-flare/touchdown: Nose over/nose down](https://openairdocs.org/ntsb-events/096); cases with it: [Grumman G-164A, 11 cases](https://openairdocs.org/ntsb-events/096/sequence.md?model=3952704), [All aircraft, 2,287 cases](https://openairdocs.org/ntsb-events/096/sequence.md) ## 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. ## Factual narrative 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. ## Aircraft - Registration: [N6637](https://openairdocs.org/deregistered/N6637-2021-05-08), registration cancelled 2021-05-08, S/N 766, built 1970 (OpenAirDocs) - Reported make and model: GRUMMAN G 164A - Registry model: [Grumman G-164A](https://openairdocs.org/model/grumman-g-164a) (registry code 3952704) (OpenAirDocs) - Registry engine: [Pratt & Whitney R-985-AN-1](https://openairdocs.org/engine/pratt-whitney-r-985-an-1) (registry code 51659, reciprocating) (OpenAirDocs) - Category: Airplane - Serial number: 766 - Year built: 1970 - Airframe hours: 17000 - Engines: Pratt & Whitney R-1340-AN1 600 horsepower reciprocating - Damage: Substantial damage - Flight: Aerial application, Part 137 - Operator: Aero Ag Services Inc - Registered owner: Aero Ag Services Inc - Airworthiness certificate: Special, Restricted (Special) - Last inspection: Annual, February 28, 2018, 20 hours before - Departed: PVT, Garwood, TX - Destination: PVT, Garwood, TX - Airport: PVT, Private ## Flight crew As NTSB recorded them. NTSB leaves out names. - Pilot; age 29; injuries: none; commercial; airplane ratings: single-engine land; medical: class 2, without waivers/limitations; last flight review January 5, 2017; seat: center; restraint: 4-point; flight hours: 2,140 total, 1,125 in this make and model, 2,115 as pilot in command, 240 in the last 90 days, 40 in the last 30 days, 6 in the last 24 hours ## Weather - Conditions: Visual (VMC), Day - Wind: 10° at 7 knots - Visibility: 10 statute miles - Lowest ceiling: none - Temperature: 77 °F, dew point 48 °F - Altimeter: 30.01 inHg - Observed at: KARM, 23 nm away ## FAA reports on this event (1) The FAA's own accident and incident reports, matched to the aircraft by N-number and date (OpenAirDocs). - [Accident 20180427004199A](https://openairdocs.org/incident/20180427004199A), Apr 27, 2018: Grumman G-164A, Garwood, TX, Destroyed. On 04/27/2018 pilot took off from heiman (private) strip in N6637. After rotation he reported that the aircraft lost power and he was forced to land in a field… ## Other investigations on N6637 (1) From the NTSB's public API. Aircraft are matched to registry aircraft by N-number and event date, checked against the reported serial number, make and model; the registry's history has gaps, so older matches can be wrong. Compare the reported make and model. - [NTSB FTW00LA098](https://openairdocs.org/ntsb/FTW00LA098), Mar 13, 2000: Grumman G-164A (N6637), Garwood, TX, substantial damage. Probable cause: The failure of the left magneto, which resulted in the partial loss of engine power during takeoff. ## Docket (3 files) The files NTSB released with the investigation on October 4, 2018, on NTSB's docket system: https://data.ntsb.gov/Docket?ProjectID=97131. 426 KB in all. - Pilot/Operator Aircraft Accident Report, NTSB Form 6120.1 (item 1, .PDF, 282 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40467195&FileExtension=.PDF&FileName=Pilot%2FOperator%20Aircraft%20Accident%20Report,%20NTSB%20Form%206120.1-Master.PDF - Teardown Report (item 2, .PDF, 77 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40467197&FileExtension=.PDF&FileName=Teardown%20Report-Master.PDF - Carburetor Icing Probability Chart (item 3, .PDF, 67 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40467199&FileExtension=.PDF&FileName=Carburetor%20Icing%20Probability%20Chart-Master.PDF From the NTSB's public API. Aircraft are matched to registry aircraft by N-number and event date, checked against the reported serial number, make and model; the registry's history has gaps, so older matches can be wrong. Compare the reported make and model. --- OpenAirDocs.org is an independent research project of [Contrail Labs](https://contraillabs.com/). It is not affiliated with the FAA or the NTSB. Source documents are U.S. government works in the public domain.