# NTSB ATL03LA059: Aeronca 7AC, N1648E, Gordo, AL, March 7, 2003 - Type: NTSB accident investigation - Classification: Accident · No injuries · Limited investigation · Final report - Date: March 7, 2003, 17:45 local (23:45 UTC) - Place: Gordo, AL - Coordinates: 33.388889, -88.005554 - Nearby events: https://openairdocs.org/map.md?lat=33.3889&lon=-88.0056&mi=10 - Phase of flight: [Enroute](https://openairdocs.org/ntsb-phases/400) (OpenAirDocs' grouping) - Highest injury: No injuries - Injuries: 2 uninjured - Status: Completed, report June 28, 2006 - Report: Approved by Office Director - Parties: Birmingham FSDO - NTSB case key (mKey): 56612 - NTSB case page: https://web.ntsb.gov/investigations/?ntsbnumber=ATL03LA059 - NTSB report (PDF, downloads): https://data.ntsb.gov/carol-repgen/api/Aviation/ReportMain/GenerateNewestReport/56612/pdf - Page: https://openairdocs.org/ntsb/ATL03LA059 ## Probable cause Fatigue failure of the crankshaft. ## Sequence of events In NTSB's coding before 2008 (https://www.ntsb.gov/GILS/Documents/codman.pdf). - Airframe/component/system failure/malfunction, cruise - engine assembly,crankshaft - fatigue (cause) - Loss of engine power(total) - mech failure/malf, cruise - Forced landing, descent - emergency - On ground/water encounter with terrain/water, emergency landing - terrain condition - water (contributing factor) ## Analysis During cruise flight a "bump" was felt under the pilot's seat, then the airplane pitched up erratically and became difficult to control. The pilot selected an open field and executed an emergency landing. The airplane came to rest in a pond. The pilot reported that the crankshaft sheared behind the propeller flange and in front of the crankcase. Examination of the airplane on site revealed that one of the propeller blades separated at the flange, there was substantial damage to the nose bowl cowling due to the airplane nosing over into the pond. The firewall was bent slightly rearward at the base and there was also water damage to the wing spar. Further examination of the partial crankshaft recovered, revealed that the separation had occurred between the oil slinger and the propeller mounting flanges leaving a fracture face. The fracture face displayed arced crack arrest marks, consistent with fatigue propagation. The arcing of the crack arrest marks indicated that the fatigue origin was located further forward, towards the propeller-mounting flange on the unrecovered portion of the crankshaft. ## Factual narrative On March 7, 2003, at 1745 central standard time, an Aeronca 7AC, N1648E, registered to and operated by a private owner, propeller blade separated in-flight, and the pilot conducted an emergency landing near Gordo, Alabama. The personal flight was operated under the provisions of Title 14 CFR Part 91 with no flight plan filed. Visual meteorological conditions prevailed at the time of the accident. The airplane sustained substantial damage, and the pilot and passenger were not injured. The flight originated from Tuscaloosa Municipal Airport, Tuscaloosa, Alabama, at 1700 on March 7, 2003. According to the pilot, during cruise flight a "bump" was felt under his seat, then the airplane pitched up erratically and became difficult to control. The pilot selected an open field and executed an emergency landing. The airplane came to rest in a feeder pond. The pilot reported that the crankshaft sheared behind the propeller flange and in front of the crankcase. There was 2391 hours total time on the part and 2170 hours total time at overhaul. Examination of the airplane on site revealed one of the propeller blades separated at the flange, substantial damage to the nose bowl cowling due to aircraft nosing over into pond, firewall bent slightly rearward at base and water damage to wing spar. Further examination of the partial crankshaft recovered revealed that the separation had occurred between the oil slinger and the propeller mounting flanges leaving a fracture face inclined at approximately 45 degrees to the longitudinal axis of the crankshaft. The fracture face displayed arced crack arrest marks, consistent with fatigue propagation. The arcing of the crack arrest marks showed that the fatigue origin was located further forward, towards the propeller-mounting flange on the unrecovered portion of the crankshaft. ## Aircraft - Registration: [N1648E](https://openairdocs.org/aircraft/N1648E), registered now, S/N 7AC-5213, built 1946 (OpenAirDocs) - Reported make and model: Aeronca 7AC - Registry model: [Aeronca 7AC](https://openairdocs.org/model/aeronca-7ac) (registry code 2110102) (OpenAirDocs) - Registry engine: [Continental A&C65 series](https://openairdocs.org/engine/continental-a-c65-series) (registry code 17003, reciprocating) (OpenAirDocs) - Category: Airplane - Serial number: 7AC-5213 - Airframe hours: 2391 - Engines: Continental A65-8 65 horsepower reciprocating - Damage: Substantial damage - Flight: Personal, Part 91 - Registered owner: Carole Anne Taylor - Airworthiness certificate: Standard, Normal - Last inspection: Annual, February 11, 2003, 1.2 hours before - Departed: KTCL, Tuscaloosa, AL ## Flight crew As NTSB recorded them. NTSB leaves out names. - Pilot; age 46; injuries: none; flight instructor, airline transport, commercial; airplane ratings: single-engine land, single-engine sea, multi-engine land; instrument ratings: airplane; medical: class 2, valid medical--w/ waivers/lim; last flight review August 15, 2002; seat: front; flight hours: 2,874 total, 705 in this make and model, 2,789 as pilot in command, 75 in the last 90 days, 36 in the last 30 days, 3 in the last 24 hours ## Weather - Conditions: Visual (VMC), Day - Wind: 60° at 3 knots - Visibility: 10 statute miles - Lowest ceiling: none - Temperature: 70 °F, dew point 48 °F - Altimeter: 30.04 inHg - Observed at: tcl, 20 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 20030307013949A](https://openairdocs.org/incident/20030307013949A), Mar 7, 2003: Bbavia 7AC, Gordo, AL, Substantial damage. (-23) The airplane departed the tuscaloosa al airport with the pilot and one passenger. The propeller departed the airplane during cruise flight. The… ## Other investigations on N1648E (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 MIA68D0405](https://openairdocs.org/ntsb/MIA68D0405), Jan 31, 1968: Aeronca 7AC (N1648E), Jacksboro, TN, 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.