# NTSB CHI99LA092: Cessna 172RG, N9506D, Lawrenceville, IL, February 15, 1999 - Type: NTSB accident investigation - Classification: Accident · No injuries · Limited investigation · Final report - Date: February 15, 1999, 15:15 local (21:15 UTC) - Place: Lawrenceville, IL - Coordinates: 38.719856, -87.679969 (estimated) - Nearby events: https://openairdocs.org/map.md?lat=38.7199&lon=-87.6800&mi=10 - Phase of flight: [Initial climb](https://openairdocs.org/ntsb-phases/350) (OpenAirDocs' grouping) - Highest injury: No injuries - Injuries: 2 uninjured - Status: Completed, report June 22, 2000 - Report: Approved by Office Director - NTSB case key (mKey): 45756 - NTSB case page: https://web.ntsb.gov/investigations/?ntsbnumber=CHI99LA092 - NTSB report (PDF, downloads): https://data.ntsb.gov/carol-repgen/api/Aviation/ReportMain/GenerateNewestReport/45756/pdf - Page: https://openairdocs.org/ntsb/CHI99LA092 ## Probable cause the fatigue fracture of the landing gear actuator. ## Sequence of events In NTSB's coding before 2008 (https://www.ntsb.gov/GILS/Documents/codman.pdf). - Airframe/component/system failure/malfunction, takeoff - initial climb - landing gear,normal retraction/extension assembly - failure,total (cause) - landing gear,normal retraction/extension assembly - fatigue (cause) - acft/equip,inadequate design, manufacturer (cause) - On ground/water encounter with terrain/water, landing - roll ## Analysis During climb-out both pilots heard a pop from the right side of the aircraft under the right seat. The CFI performed a landing gear extension. The left landing gear would extend and lock, but the right main gear would extend partially and then retract simultaneously as the left main landing gear would lower and lock. The manual landing gear extension procedures were tried, but the right main landing gear failed to extend. An emergency landing was attempted. The airplane veered off the right side of the runway during the landing rollout. The right wing and right horizontal stabilizer were damaged when they impacted the ground. The examination of the right main landing gear actuator assembly revealed the actuator body was cracked in two locations near the cups for the bearings. One of the cracks had fatigue striations that originated at the corner formed by the intersection of the 2.25 inch inner-diameter surface of the gear housing and the 1.0 inch inner-diameter surface of the linear actuator portion of the actuator housing. The examination of the corner revealed the presence of circumferential scouring marks consistent with grinding or filing marks. The maintenance logbooks indicated that the landing gear actuator was originally equipped on the airplane and had a total of approximately 7,000 flight hours and 21,000 cycles. There is no life or component time limit listed for the component by the airplane manufacturer. ## Factual narrative On February 15, 1999, at 1515 central standard time, a Cessna 172RG, N9506D, operated by Vincennes University, was substantially damaged during landing. The Certified Flight Instructor (CFI) reported the right main landing gear failed to extend during landing. The CFI and dual student were not injured. The 14 CFR Part 91 flight had departed Lawrenceville, Illinois, at 1500 CST on a local instructional flight. Visual meteorological conditions prevailed and no flight plan had been filed. The CFI reported that during the climb-out both pilots heard a pop from the right side of the aircraft under the right seat. The CFI performed a landing gear extension. The CFI reported the left landing gear would extend and lock, but the right main gear would extend partially and then retract simultaneously as the left main landing gear would lower and lock. The CFI reported that the manual landing gear extension procedures were tried, but the right main landing gear failed to extend. The landing gear unsafe indicator illuminated. The CFI reported he circled overhead the airport for 1.5 hours before executing an emergency landing. The landing was made with the nose wheel and the left landing gear in the down position. The right gear remained in the retracted position. The CFI reported the airplane veered off the right side of the runway during the landing rollout. The right wing and right horizontal stabilizer were damaged when they impacted the ground. The right main landing gear actuator assembly, p/n 9882015-2, was sent to the National Transportation Safety Board's Materials Laboratory for examination. The examination revealed the actuator body was cracked in two locations near the cups for the bearings. The inspection of the cracks revealed that one of the cracks had fatigue striations that originated at the corner formed by the intersection of the 2.25 inch inner-diameter surface of the gear housing and the 1.0 inch inner-diameter surface of the linear actuator portion of the actuator housing. The examination of the corner revealed the presence of circumferential scouring marks consistent with grinding or filing marks. (See Materials Laboratory Factual Report) A review of the maintenance logbooks indicated that the landing gear actuator was originally equipped on the airplane and had a total of approximately 7,000 flight hours and 21,000 cycles. There is no life or component time limit listed for the component by the airplane manufacturer. ## Aircraft - Registration: [N9506D](https://openairdocs.org/deregistered/N9506D-2013-07-03), registration cancelled 2013-07-03, S/N 172S11315 (OpenAirDocs) - Reported make and model: Cessna 172RG - Registry model: [Cessna 172S](https://openairdocs.org/model/cessna-172s) (registry code 2072439) (OpenAirDocs) - Category: Airplane - Serial number: 172RG1191 - Airframe hours: 7024 - Engines: Lycoming O-360-F1A6 180 horsepower reciprocating - Damage: Substantial damage - Flight: Instructional, Part 91 - Registered owner: Vincennes University - Airworthiness certificate: Standard, Normal - Last inspection: Annual, January 20, 1999, 32 hours before - Departed: LWV - Airport: LWV, Lawrenceville Airport, runway 18, 5,200 × 100 ft, asphalt ## Flight crew As NTSB recorded them. NTSB leaves out names. - Pilot; age 30; commercial; airplane ratings: single-engine land, multi-engine land; instrument ratings: airplane; medical: class 1, valid medical--no waivers/lim.; seat: right; flight hours: 1,396 total, 76 in this make and model, 1,264 as pilot in command, 171 in the last 90 days, 67 in the last 30 days ## Weather - Conditions: Visual (VMC), Day - Wind: 180° at 15 knots - Visibility: 10 statute miles - Lowest ceiling: none - Temperature: 55 °F - Altimeter: 30.00 inHg - Observed at: LWV ## 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 19990215001469A](https://openairdocs.org/incident/19990215001469A), Feb 15, 1999: Cessna 172RG, Lawrenceville, IL, Substantial damage. Acft right main landing gear did not extend on landing. (.19) on February 15, 1999, at 1515 central standard time, a Cessna 172RG, N9506D, operated by… 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.