# NTSB FTW96LA025: Piper PA-28R-180, N7471J, Dibble, OK, October 24, 1995 - Type: NTSB accident investigation - Classification: Accident · Minor injuries · Limited investigation · Final report - Date: October 24, 1995, 11:25 local (16:25 UTC) - Place: Dibble, OK - Location: 35.0197° N, 97.6271° W: Placed by OpenAirDocs: center of Dibble, OK, within about 6 miles (OpenAirDocs) - Nearby events: https://openairdocs.org/map.md?lat=35.0197&lon=-97.6271&mi=10 - Phase of flight: [Maneuvering](https://openairdocs.org/ntsb-phases/450) (OpenAirDocs' grouping) - Highest injury: Minor injuries - Injuries: 1 minor, 2 uninjured - Status: Completed, report September 24, 1996 - Report: Approved by Office Director - NTSB case key (mKey): 19695 - NTSB case page: https://web.ntsb.gov/investigations/?ntsbnumber=FTW96LA025 - NTSB report (PDF, downloads): https://data.ntsb.gov/carol-repgen/api/Aviation/ReportMain/GenerateNewestReport/19695/pdf - Page: https://openairdocs.org/ntsb/FTW96LA025 ## Probable cause an overload failure of the #1 connecting rod bolt and resulting connecting rod fatigue failure. A factor was the lack of suitable terrain for the forced landing. ## Sequence of events In NTSB's coding before 2008 (https://www.ntsb.gov/GILS/Documents/codman.pdf). - Loss of engine power(total) - mech failure/malf, maneuvering - engine assembly,connecting rod cap - loose part/bolt/nut/clamp/etc - engine assembly,connecting rod bolt - overload (cause) - engine assembly,connecting rod - fatigue (cause) - Forced landing, emergency landing - On ground/water encounter with terrain/water, landing - roll - terrain condition - none suitable (contributing factor) - object - fence - terrain condition - ditch ## Analysis While practicing maneuvers at 3,500 feet, the pilots heard a loud noise and the windshield became covered with oil. During the ensuing forced landing, the airplane collided with a fence and ditch. Engine disassembly revealed the #4 connecting rod had fractured. The #2 and #4 top connecting rod nuts were loose. Metallurgical examination disclosed the #4 bottom connecting rod bolt had failed in overload and the #4 connecting rod had failed from high stress, low cycle fatigue. ## Factual narrative On October 24, 1995, approximately 1125 central daylight time, a Piper PA-28R-180, N7471J, operated by Airman Flight School, was substantially damaged when it collided with terrain during a forced landing near Dibble, Oklahoma. The commercial flight instructor received minor injuries, and the commercial pilot receiving flight instruction and another commercial pilot-rated passenger were not injured. Visual meteorological conditions prevailed and no flight plan was filed for this instructional flight being conducted under Title 14 CFR Part 91. The local flight originated at Norman, Oklahoma, on October 24, 1995, approximately 1 hour, 25 minutes before the accident. The following is based on the Pilot/Operator Report and a conversation the flight instructor had with a Federal Aviation Administration inspector. The pilots were practicing maneuvers at 3,500 feet msl (above mean sea level) when they heard a loud noise. The airplane began to shake and oil covered the windshield. The instructor took control of the airplane, secured the engine, and made a forced landing in a field. The airplane went through a fence, across a road, and collided with a ditch. The engine was disassembled and examined at Textron Lycoming and observed by a Federal Aviation Administration inspector. The #4 connecting rod was fractured in the bearing bore area. One connecting rod bolt was broken with the head end remaining with the end cap. The threaded end of this bolt and the nut were not recovered. The other connecting rod bolt was not recovered. A connecting rod nut was found embedded near the #1 cylinder bore. An imprint of the threaded end of a connecting rod bolt with a nut installed was observed near the #4 tappet bosses. One of the #1 connecting rod nuts was loose and the other was "somewhat tight." Examination of the undamaged fracture surfaces of the #4 connecting rod bolt disclosed a failure mode consistent with overload. Metallurgical examination revealed all failed components met design material specifications. It was the opinion of Textron Lycoming that the #2 and #4 top connecting rod nuts had loosened and had separated from their respective bolts. This caused the no. 4 bottom bolt to fail from overload. The no. 4 connecting rod then failed from high stress, low cycle fatigue. Examination of the maintenance records disclosed that at the time of the accident, the engine had accrued 3,083 total hours. The engine was overhauled on June 19, 1978, and received a top overhaul on April 18, 1991. At the time of the accident, the engine had accrued 1,894 hours and 1,096 hours since major overhaul and top overhaul, respectively. ## Aircraft - Registration: [N7471J](https://openairdocs.org/deregistered/N7471J-2018-01-29), registration cancelled 2018-01-29, S/N 28R-30824, built 1968 (OpenAirDocs) - Reported make and model: PIPER PA-28R-180 - Registry model: [Piper PA-28R-180](https://openairdocs.org/model/piper-pa-28r-180) (registry code 7102809) (OpenAirDocs) - Registry engine: [Lycoming I0360 series](https://openairdocs.org/engine/lycoming-i0360-series) (registry code 41515, reciprocating) (OpenAirDocs) - Category: Airplane - Serial number: 28R-30824 - Engines: LYCOMING IO-360-B1A 180 horsepower reciprocating - Damage: Substantial damage - Flight: Instructional, Part 91 - Registered owner: Airman Flight School, Inc. - Airworthiness certificate: Standard, Normal - Last inspection: 100 hour, October 2, 1995, 39 hours before - Departed: OUN, NORMAN, OK ## Flight crew As NTSB recorded them. NTSB leaves out names. - Pilot; age 25; flight instructor, commercial; airplane ratings: single-engine land, multi-engine land; instrument ratings: airplane; medical: class 1, valid medical--w/ waivers/lim; seat: left; flight hours: 1,305 total, 157 in this make and model, 1,218 as pilot in command, 327 in the last 90 days, 141 in the last 30 days, 5 in the last 24 hours ## Weather - Conditions: Visual (VMC), Day - Wind: 70° at 4 knots - Visibility: 10 statute miles - Lowest ceiling: none - Temperature: 55 °F, dew point 27 °F - Altimeter: 30.00 inHg - Observed at: OKC, 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 19951024034499A](https://openairdocs.org/incident/19951024034499A), Oct 24, 1995: Piper PA28R180, Dibble, OK, Substantial damage. During dual at 3500 ft. loud noise oil on windshield. Collided with ditch landing. Lost rod bolts. Rods thru case. ## Other investigations on N7471J (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 LAX70FUG09](https://openairdocs.org/ntsb/LAX70FUG09), Feb 18, 1970: Piper PA-28R (N7471J), Big Bear City, CA, destroyed 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.