# NTSB ATL93LA149: American AA-1, N5765L, Tuscaloosa, AL, September 4, 1993 - Type: NTSB accident investigation - Classification: Accident · Minor injuries · Limited investigation · Final report - Date: September 4, 1993, 14:55 local (19:55 UTC) - Place: Tuscaloosa, AL - Coordinates: 33.229019, -87.540344 (estimated) - Nearby events: https://openairdocs.org/map.md?lat=33.2290&lon=-87.5403&mi=10 - Phase of flight: [Initial climb](https://openairdocs.org/ntsb-phases/350) (OpenAirDocs' grouping) - Highest injury: Minor injuries - Injuries: 1 minor - Status: Completed, report October 20, 1994 - Report: Approved by Office Director - NTSB case key (mKey): 3257 - NTSB case page: https://web.ntsb.gov/investigations/?ntsbnumber=ATL93LA149 - NTSB report (PDF, downloads): https://data.ntsb.gov/carol-repgen/api/Aviation/ReportMain/GenerateNewestReport/3257/pdf - Page: https://openairdocs.org/ntsb/ATL93LA149 ## Probable cause FOULED SPARK PLUGS ON THE NUMBER 2 AND 3 CYLINDERS, AND A LACK OF COMPRESSION ON THE NUMBER 1 AND 4 CYLINDERS, WHICH RESULTED IN A LOSS OF ENGINE POWER. A FACTOR WAS THE HIGH VEGETATION AT THE FORCED LANDING SITE. ## Sequence of events In NTSB's coding before 2008 (https://www.ntsb.gov/GILS/Documents/codman.pdf). - Loss of engine power, takeoff - initial climb - engine assembly,cylinder - low compression (cause) - ignition system,spark plug - fouled (cause) - Forced landing, descent - emergency - In flight collision with terrain/water, landing - flare/touchdown - terrain condition - high vegetation (contributing factor) ## Analysis THE PILOT REPORTED THAT THE ENGINE RPM BEGAN TO DECAY DURING THE INITIAL CLIMB AFTER TAKEOFF. UNABLE TO MAINTAIN ALTITUDE, HE MANEUVERED THE AIRCRAFT TO A NEARBY FIELD. HE FORCE LANDED THE AIRCRAFT IN HIGH GRASS, THE LANDING GEAR COLLAPSED, AND THE AIRFRAME RECEIVED STRUCTURAL DAMAGE. AN INSPECTION OF THE ENGINE REVEALED THAT THE NUMBER 2 AND 3 CYLINDER SPARK PLUGS WERE FOULED, AND WOULD NOT PRODUCE A SPARK. A COMPRESSION CHECK SHOWED NO COMPRESSION ON THE NUMBERS 1 AND 4 CYLINDERS. ## Factual narrative On September 4, 1993, at about 1455 central daylight time, an American AA-1, N5765L, was substantially damaged following a forced landing near Tuscaloosa, Alabama. The private pilot had minor injuries. The aircraft was operated under 14 CFR Part 91 by the pilot. Visual meteorological conditions prevailed at the time, and no flight plan was filed for the personal flight to Montgomery, Alabama. The flight was originating at the time of the accident. The pilot reported the following: During ground operations, he performed a magneto check, and noted a 100 rpm drop (both left and right magnetos). During the initial climb after takeoff, the engine rpm dropped from 2,500 to 2,300. After checking the magnetos and carburetor heat once again, the rpm continued to decay to about 1,200 rpm. Unable to make it back to the airport, he maneuvered the aircraft towards the closest field. He force landed the airplane in a field of high weeds. All three landing gear broke off during the landing roll, and structural damage to the airframe resulted. An inspector with the Federal Aviation Administration examined the aircraft following the accident. He reported the following: Clean, contaminant-free fuel was found in the fuel tanks, fuel lines, and carburetor. The electric fuel boost pump and engine driven fuel pump worked properly. The induction system tubes were sealed, and the air filter was clean. A compression check was performed on the engine; the numbers 1 and 4 cylinders would not develop compression. An examination of the spark plugs revealed that the numbers 1 and 4 cylinder plugs had dry, black soot deposits on the electrodes. The numbers 2 and 3 cylinder plugs were lead fouled, and would not produce a spark. These plugs were also carbon-fouled. ## Aircraft - Registration: [N5765L](https://openairdocs.org/deregistered/N5765L-2013-06-07), registration cancelled 2013-06-07, S/N AA1-0165, built 1969 (OpenAirDocs) - Reported make and model: AMERICAN AA-1 - Registry model: [American AA-1](https://openairdocs.org/model/american-aa-1) (registry code 0630610) (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: AA1-0165 - Airframe hours: 1571 - Engines: LYCOMING O-235-C2C 108 horsepower reciprocating - Damage: Substantial damage - Flight: Personal, Part 91 - Operator: Curenton, Rufus B. - Registered owner: Sturges, James T. - Airworthiness certificate: Standard, Utility - Last inspection: Annual, June 1, 1993, 9 hours before - Destination: MGM, MONTGOMERY, AL - Airport: TCL, Tuscaloosa Municipal, runway 29, 4,001 × 150 ft, asphalt ## Flight crew As NTSB recorded them. NTSB leaves out names. - Pilot; age 39; private; airplane ratings: single-engine land; instrument ratings: airplane; medical: class 3, valid medical--w/ waivers/lim; seat: left; flight hours: 278 total, 1 in this make and model, 220 as pilot in command, 44 in the last 90 days, 16 in the last 30 days ## Weather - Conditions: Visual (VMC), Day - Visibility: 10 statute miles - Lowest ceiling: none - Temperature: 86 °F, dew point 66 °F - Altimeter: 29.00 inHg - Observed at: TCL, 1 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 19930904032979A](https://openairdocs.org/incident/19930904032979A), Sep 4, 1993: Gulstm AA1, Tuscaloosa, AL, Substantial damage. Lost power on climbout. Landed in brush covered field. Wiped off all three gear no compression in nr 1/4 cylinder. ## Other investigations on N5765L (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 IAD80FIJ01](https://openairdocs.org/ntsb/IAD80FIJ01), Apr 7, 1980: Grum Amer AA-1A (N5765L), Galax, VA, substantial damage 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.