# NTSB MIA01LA167: Grumman American AA-1B, N8957L, Oak Hill, FL, June 19, 2001 - Type: NTSB accident investigation - Classification: Accident · No injuries · Limited investigation · Final report - Date: June 19, 2001, 10:45 local (14:45 UTC) - Place: Oak Hill, FL - Coordinates: 28.859092, -80.849433 (estimated) - Nearby events: https://openairdocs.org/map.md?lat=28.8591&lon=-80.8494&mi=10 - Phase of flight: [Enroute](https://openairdocs.org/ntsb-phases/400) (OpenAirDocs' grouping) - Highest injury: No injuries - Injuries: 2 uninjured - Status: Completed, report November 6, 2001 - Report: Approved by Office Director - Parties: FAA FSDO - NTSB case key (mKey): 52520 - NTSB case page: https://web.ntsb.gov/investigations/?ntsbnumber=MIA01LA167 - NTSB report (PDF, downloads): https://data.ntsb.gov/carol-repgen/api/Aviation/ReportMain/GenerateNewestReport/52520/pdf - Page: https://openairdocs.org/ntsb/MIA01LA167 ## Probable cause A partial loss of engine power while at a low altitude cruise due to fuel contamination, and the subsequent emergency descent and landing to a rural road resulting in collision with tree and mailbox post. ## Sequence of events In NTSB's coding before 2008 (https://www.ntsb.gov/GILS/Documents/codman.pdf). - Loss of engine power(partial) - nonmechanical, cruise - fluid,fuel - contamination,other than water (cause) - In flight collision with object, emergency descent/landing - object - tree(s) - object - other ## Analysis According to the pilot, 15 minutes after departure and 5 minutes after switching fuel source from left wing tank to right wing tank, he started losing engine rpm's as well as fuel pressure indications. He was at such an altitude, (1,200 feet, agl) that he had no time to complete the "engine failure during cruise" checklist, and executed an emergency landing to a rural road. The pilot and a passenger escaped injury, but the aircraft sustained substantial damage. Postcrash testing of all fuel and ignition components, as well as the core engine revealed no malfunctions. Evidence of fuel contamination was found in fuel samples taken from the carburetor bowl, and disassembly examination of the carburetor revealed other, caked contaminate in the recesses of the carburetor bowl. The aircraft was STC'ed for use of automotive fuel, and 87 octane automotive fuel was being used at the time of the accident. ## Factual narrative On June 19, 2001, about 1045 eastern daylight time, a Grumman American AA-1B, N8957L, registered to a private individual, operating as a 14 CFR Part 91 personal flight, crashed while attempting a forced landing in the vicinity of Oak Hill, Florida. Visual meteorological conditions prevailed and no flight plan was filed. The airplane received substantial damage and the private-rated pilot and a passenger were not injured. The flight originated from Space Coast Regional Airport, Titusville, Florida, about 15 minutes before the accident. According to the pilot, he had routinely switched his fuel source from the left tank to the right tank about 8 minutes before he started losing rpm and fuel pressure. He switched the fuel selector back to the left tank, but engine speed continued to decay to under 500 rpm, although it did not quit completely. He was at 1,200 feet msl, and did not have time to accomplish the entire "engine failure in flight" checklist. He did not attempt using carburetor heat. The aircraft was properly approved for the FAA supplemental type certificate for use of automotive fuel and 87 octane automotive fuel was being used at the time. According to an FAA inspector, the pilot chose an unpaved road about the same width as the wing span, and on landing rollout, the right wing collided with mailboxes and a palm tree that separated the wing, (and landing gear) near the wing root. The right wing tank was compromised during the crash sequence, and evidence of fuel spillage was present. The right wing contained about 1 gallon of auto fuel and the left wing contained about 6 or 7 gallons of auto fuel. During post crash examination of the Lycoming O-235-C2C engine at an aircraft maintenance facility with FAA oversight, all fuel and ignition components were inspected for possible causes of the symptoms reported by the pilot during the engine loss of power. A small amount of fine particulate matter was found in the 4 or 5 oz. of auto fuel drained from the carburetor bowl, although all filter screens in the fuel system were clean and unobstructed. The inspector characterized the contamination as, "...light to moderate muddiness, such as silt in suspension." The carburetor bowl assembly was removed from the carburetor, and an additional small amount of encrusted residue was visible. It was decided to continue the operational checks without removing the carburetor bowl contaminate. Two attempts were made to test run the engine, but after satisfactory starts, the engine would abruptly shut down of its own accord. On the third attempt, using throttle manipulation to prevent another shutdown, run time was adequate to operationally test the magnetos, and both tested normal. The indicated fuel pressure, with and without the boost pump on, was 4 to 5 psi, which is in the normal range. Removal and reinstallation of the carburetor to another engine for operational testing revealed normal performance of the carburetor. All components of the fuel and ignition systems were again re-examined, including the boost pump, the engine driven pump, the fuel lines, the fuel selector valve, both magnetos, the magneto p-leads, and the magneto switch. All components again tested normally. The carburetor, a Marvel Schebler, model MA-3A, PN 10-3103-1, Serial No. Y-29-5001, was subjected to FAA repair station disassembly examination, with NTSB oversight. The carburetor bowl contained an amount of encrusted, tan-colored residue within its angular recesses, that when scraped and deposited on a napkin, amounted to about 1/4 gram. Testing of the carburetor on a fuel flow tester revealed the float level was properly adjusted. The main nozzle was the correct part number for its application, and the fuel flow rate was to specification. The venturi assembly was found misaligned with respect to its relationship with the main nozzle, but it was seated squarely within the carburetor throat into its machined mating surface and would not have been a factor as to correct fuel/air flow or engine performance. Although the atmospheric conditions existing at the time of the original engine power loss put the flight in the regime of, "serious icing at glide power" on the icing probability charts, this line of investigation was not pursued since the engine exhibited the same power instability during postcrash testing at the maintenance facility. ## Aircraft - Registration: [N8957L](https://openairdocs.org/deregistered/N8957L-2013-05-17), registration cancelled 2013-05-17, S/N AA1B-0407, built 1974 (OpenAirDocs) - Reported make and model: Grumman American AA-1B - Registry model: [Grumman American Avn. AA-1B](https://openairdocs.org/model/grumman-american-avn-aa-1b) (registry code 3960103) (OpenAirDocs) - Registry engine: [Lycoming 0-235 series](https://openairdocs.org/engine/lycoming-0-235-series) (registry code 41505, 4 cycle) (OpenAirDocs) - Category: Airplane - Serial number: AA!B-0407 - Airframe hours: 3299 - Engines: Lycoming O-235-C2C 108 horsepower reciprocating - Damage: Substantial damage - Flight: Personal, Part 91 - Registered owner: Raymond Bridges - Airworthiness certificate: Standard, Normal - Last inspection: Annual, August 9, 2000, 78 hours before - Departed: TIX, Space Coast Reg, FL - Destination: EVB, New Smyrna, FL ## Flight crew As NTSB recorded them. NTSB leaves out names. - Pilot; age 23; injuries: none; private; airplane ratings: single-engine land; medical: class 3, valid medical--no waivers/lim.; last flight review December 20, 2000; seat: left; flight hours: 116 total, 48 in this make and model, 81 as pilot in command, 48 in the last 90 days, 25 in the last 30 days ## Weather - Conditions: Visual (VMC), Day - Wind: 40° at 6 knots - Visibility: 5 statute miles - Lowest ceiling: 13,000 ft broken - Temperature: 82 °F, dew point 64 °F - Altimeter: 30.17 inHg - Observed at: TIX, 21 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 20010619024209A](https://openairdocs.org/incident/20010619024209A), Jun 19, 2001: Amrgen AA1B, Oak Hill, FL, Substantial damage. (-23) The engine reportedly lost power during cruise at 1,200 ft. AGL, about 8 minutes after the PIC switched fuel tanks. The boost pump was reportedly on at… 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.