# NTSB MIA96LA041: Mckibben GN-1 Aircamper, N823GM, Mayhew, MS, December 12, 1995 - Type: NTSB accident investigation - Classification: Accident · No injuries · Limited investigation · Final report - Date: December 12, 1995, 16:25 local (22:25 UTC) - Place: Mayhew, MS - Location: 33.4848° N, 88.6345° W: Placed by OpenAirDocs: center of Mayhew, MS, within about 6 miles (OpenAirDocs) - Nearby events: https://openairdocs.org/map.md?lat=33.4848&lon=-88.6345&mi=10 - Phase of flight: [Takeoff](https://openairdocs.org/ntsb-phases/300) (OpenAirDocs' grouping) - Highest injury: No injuries - Injuries: 1 uninjured - Status: Completed, report June 7, 1996 - Report: Approved by Office Director - NTSB case key (mKey): 37959 - NTSB case page: https://web.ntsb.gov/investigations/?ntsbnumber=MIA96LA041 - NTSB report (PDF, downloads): https://data.ntsb.gov/carol-repgen/api/Aviation/ReportMain/GenerateNewestReport/37959/pdf - Page: https://openairdocs.org/ntsb/MIA96LA041 ## Probable cause The pilot's improper planning/decision, and failure to verify the airplane's performance data. The airplane's lack of climb capability with the newly manufactured propeller was a related factor. ## Sequence of events In NTSB's coding before 2008 (https://www.ntsb.gov/GILS/Documents/codman.pdf). - In flight collision with object, takeoff - planning/decision - improper, pilot in command (cause) - aircraft performance,climb capability - inadequate (contributing factor) - performance data - inadequate, pilot in command (cause) - object - tree(s) ## Analysis The pilot had manufactured a new propeller for his airplane. Before taking off on the first flight after certification, he performed taxi and runup tests on the engine and airplane. After takeoff, the airplane did not climb very fast and reached an altitude of only about 50 feet. After realizing that the airplane was not performing as expected, he attempted to stay over a clear field. To do this, he had to make a shallow turn, and the airplane started to descend. The airplane then struck trees at approximately 3,500 feet from the departure end of the runway. A postaccident investigation revealed no evidence of mechanical failure of the engine. When questioned, the pilot said that he expected the new propeller to produce 110 horsepower at 4500 rpm or 65 horsepower at 3000 rpm. However, during takeoff, the rpm only reached about 2600 rpm. ## Factual narrative On December 12, 1995, about 1625 central standard time, N823GM, a McKibben GN-1 Aircamper operated by a private owner as a 14 CFR part 91 personal flight, crashed in Mayhew, Mississippi. Visual meteorological conditions prevailed at the time and no flight plan was filed. The airplane was substantially damaged and the private pilot was not injured. The flight was originating at the time of the accident. The pilot stated that before to the accident he had performed 10 hours of taxi and runup tests. He had decided on the type of propeller by the designer's suggestions and he manufactured the propeller himself. He stated that his horsepower ratings were at 4,500 rpm it should be 110 horsepower and at 3,000 rpm it should be 65 horsepower. The pilot performed static runups on the engine and it came up to 2,500 rpm. During takeoff the aircraft did not accelerate as rapidly as he would have expected. The airplane did not climb very fast and reached an altitude of approximately 50 feet. After realizing the airplane was not performing as it was to be expected he attempted to stay over a clear field. To do this he had to make a shallow turn and the airplane started to descend. The airplane then struck trees about 3,500 feet from the departure end of runway 18. A post-accident investigation revealed that there was automotive fuel in the fuel tanks, fuel lines, filter, and the carburetor. There was no evidence of mechanical failure of the engine. There has been repeated requests to receive a written statement and pilot operator's report from the pilot but the pilot has ignored all requests. ## Aircraft - Registration: [N823GM](https://openairdocs.org/deregistered/N823GM-1998-04-01), registration cancelled 1998-04-01, S/N 001 (OpenAirDocs) - Reported make and model: MCKIBBEN GN-1 AIRCAMPER (GN-1 AIRCA) - Registry model: [Mckibben Gerald H GN-1 AIRCAMPER](https://openairdocs.org/model/mckibben-gerald-h-gn-1-aircamper) (registry code 05625HX) (OpenAirDocs) - Category: Airplane, amateur-built - Serial number: 2 - Engines: Corvair 65 horsepower reciprocating - Damage: Substantial damage - Flight: Part 91 - Registered owner: Gerald Mckibben - Airworthiness certificate: Special, Experimental (Special) - Departed: M51 - Airport: M51, Oktibbeha, runway 18, 2,200 × 150 ft, grass/turf ## Flight crew As NTSB recorded them. NTSB leaves out names. - Pilot; age 56; private; airplane ratings: single-engine land; medical: class 3, valid medical--w/ waivers/lim; seat: front; flight hours: 412 total, 367 as pilot in command ## Weather - Conditions: Visual (VMC), Day - Wind: 170° at 7 knots - Visibility: 7 statute miles - Lowest ceiling: 12,000 ft broken - Temperature: 59 °F, dew point 30 °F - Altimeter: 30.00 inHg - Observed at: CBM, 15 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 19951212040529A](https://openairdocs.org/incident/19951212040529A), Dec 12, 1995: Amtrgr GN1AIRCAMPER, Starkville, MS, Substantial damage. Made his own prop to his specs. On test poor acceleration and poor climb. Tried to turn. Mushed into trees. 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.