# NTSB CHI07LA011: Cessna R182, N5274S, Ames, IA, October 22, 2006 - Type: NTSB accident investigation - Classification: Accident · No injuries · Limited investigation · Final report - Date: October 22, 2006, 14:30 local (19:30 UTC) - Place: Ames, IA - Coordinates: 41.991943, -93.621948 - Nearby events: https://openairdocs.org/map.md?lat=41.9919&lon=-93.6219&mi=10 - Phase of flight: [Approach](https://openairdocs.org/ntsb-phases/500) (OpenAirDocs' grouping) - Highest injury: No injuries - Injuries: 2 uninjured - Status: Completed, report January 31, 2008 - Report: Approved by Office Director - Parties: Des Moines FSDO - NTSB case key (mKey): 64844 - NTSB case page: https://web.ntsb.gov/investigations/?ntsbnumber=CHI07LA011 - NTSB report (PDF, downloads): https://data.ntsb.gov/carol-repgen/api/Aviation/ReportMain/GenerateNewestReport/64844/pdf - Page: https://openairdocs.org/ntsb/CHI07LA011 ## Probable cause The fatigue failure of the landing gear actuator pin and the exterior visual maintenance inspection for cracks not possible by company maintenance personnel. ## Sequence of events In NTSB's coding before 2008 (https://www.ntsb.gov/GILS/Documents/codman.pdf). - Airframe/component/system failure/malfunction, approach - maintenance,inspection - not possible, company maintenance personnel (cause) - landing gear,gear locking mechanism - fatigue (cause) - maintenance,overhaul - not performed, company maintenance personnel - Nose gear collapsed, landing - roll - terrain condition - runway ## Analysis The airplane was operated as an instructional airplane when the nose landing gear collapsed during landing. The flight instructor stated that he and the dual student did not receive "a green light indicating gear down and locked" when landing. They reported cycling the landing gear several times but could not get a down and locked indication. Examination of the landing gear revealed that the two nose gear down lock actuator pins exhibited fatigue fracture over 70 percent of the fracture surface. Cessna service bulletin SEB95-20, recommends a reoccurring 200-hour inspection of the down lock pins for looseness. If looseness or movement is observed, Service kit SK210-155 is to be installed prior to further flight. The service bulletin does not provide for the visual inspection of the pins for fatigue cracks The pins were of the older design, and were reportedly inspected and no looseness was observed. Following the accident, the operator reported that one of the fractured pins was still not loose until he exerted a greater amount of force to check for looseness. ## Factual narrative On October 22, 2006, at 1430 central daylight time, a Cessna R182, N5274S, operated by Hap's Air Inc., received substantial damage on impact with terrain when the nose landing gear collapsed during landing at Ames Municipal Airport (AMW), Ames, Iowa. Visual meteorological conditions prevailed at the time of the accident. The 14 CFR Part 91 instructional flight was not operating on a flight plan. The commercial pilot and certified flight instructor (CFI) were uninjured. The local flight originated from AMW at 1400. The CFI reported that he was practicing takeoffs and landings with the commercial pilot during a dual instructional flight. During the final landing attempt, the pilots did not receive "a green light indicating gear down and locked." The pilots could visually see that the main gear was extended; however, they could not determine whether the nose gear was locked down. The pilots reported that they cycled the landing gear several times but could not get a down and locked indication. The CFI stated that during the landing, he attempted to keep "the nose wheel off of the ground as long as possible." As the airplane slowed "to nearly taxi speed," the nose gear collapsed. Inspection of the landing gear system revealed that one of the two landing gear down lock actuator pins (part number 1280209-1) was partially extended out of the nose gear actuator assembly bearing end (part number 1280600-5). The extended pin was loose and the other pin could not be moved until company maintenance personnel had to "get rough with it" and at that time looseness of the pin was noted. The pins were cylindrical steel dowels with grooves machined into the outer diameter for a transverse roll pin in the assembly. The groove was cut nearer to one end of the locking pin and oriented to the outer edges of the bearing end when assembled. The two pins and actuator bearing end were sent to the National Transportation Safety Board (NTSB) Materials Laboratory for a metallurgical examination. The pin fracture surfaces were relatively smooth, flat fracture surfaces with feature typical of fatigue progression in both pins. In both pins, the fatigue initiated at the bottom of the groove on the side nearest the longer portion of the pin. Both pins also displayed multiple fatigue origins around the groove diameter. The total fatigue area was about 75 percent of the groove cross section. Cessna issued SB SEB95-20 on December 29, 1995, recommending a reoccurring 200-hour inspection of the down lock pins for looseness. SEB95-20 stated, in part: E. Visually inspect [down lock] actuator pins while physically attempting to rotate and/or move actuator pins about all three axes in the bearing end. No movement is allowed, as pins are a press fit. F. If any looseness or movement is observed (1) Install SK210-155 prior to further flight Cessna Aircraft Company has designed and manufactured updated down lock actuator pins that have been available through SK210-155 since December 29, 1995. The incident fractured pins were of the older design, and the actuator bearing end had not been modified for installation of the newer pins. The diameters of the locking pin holes in the bearing end were measured at the outer and inner edges. At the outer edges, the hole diameters measured 0.377 inch for the left side hole and 0.376 inch for the right side hole. The diameters at the inner edges of the holes were larger, measuring 0.387 inch and 0.383 inch for the left and right holes respectively. As defined in the instructions for Cessna Service Kit SK210-155, the maximum allowable hole diameter is 0.3760 inch. The airplane was last inspected during an annual inspection on August 1, 2006, and accumulated a total time of 6,406.2 hours at the time of the accident. The company director of maintenance stated that the landing gear actuator pins were inspected within the 200-hour time frame cited in SEB95-20. There was no logbook entry pertaining to the inspection of the pins. The director of maintenance also reported that the airplane propeller (McCauley B2D34C218-13) accumulated a total time of 3,423.6 hours since last overhaul. McCauley Propeller Systems service bulletin (SB) 137W, states in part the overhaul frequency of B2D34C218 model propellers to be 2,000 hours or 72 calendar months, whichever occurs first. The NTSB investigated a fatigue failure of a landing gear actuator pin on a Cessna R182 under IAD05IA066. ## Aircraft - Registration: [N5274S](https://openairdocs.org/aircraft/N5274S), registered now, S/N R18201534, built 1980 (OpenAirDocs) - Reported make and model: Cessna R182 - Registry model: [Cessna R182](https://openairdocs.org/model/cessna-r182) (registry code 2072734) (OpenAirDocs) - Registry engine: [Lycoming O-540-J3C5D](https://openairdocs.org/engine/lycoming-o-540-j3c5d) (registry code 42361, reciprocating) (OpenAirDocs) - Category: Airplane - Serial number: R18201534 - Airframe hours: 6406.2 - Engines: Lycoming O-540-J3C5D 235 horsepower reciprocating - Damage: Substantial damage - Flight: Instructional, Part 91 - Registered owner: Hap's Air Inc. - Airworthiness certificate: Standard, Normal - Last inspection: Annual, August 1, 2006 - Departed: AMW, Ames, IA - Destination: AMW - Airport: AMW, Ames Muni, runway 31, 3,492 × 100 ft, asphalt ## Flight crew As NTSB recorded them. NTSB leaves out names. - Pilot; age 21; injuries: none; commercial; airplane ratings: single-engine land; instrument ratings: airplane; medical: class 2, with waivers/limitations; last flight review February 1, 2006; seat: rear; flight hours: 524 total, 102 in this make and model, 478 as pilot in command, 93 in the last 90 days, 12 in the last 30 days, 2 in the last 24 hours - Flight instructor; age 21; injuries: none; commercial, flight instructor; airplane ratings: single-engine land, multi-engine land; instrument ratings: airplane; medical: class 2, with waivers/limitations; last flight review March 1, 2006; seat: left; flight hours: 1,303 total, 136 in this make and model, 1,261 as pilot in command, 133 in the last 90 days, 50 in the last 30 days, 2 in the last 24 hours ## Weather - Conditions: Visual (VMC), Day - Wind: 320° at 10 knots - Visibility: 10 statute miles - Lowest ceiling: 4,900 ft overcast - Temperature: 39 °F, dew point 21 °F - Altimeter: 30.12 inHg - Observed at: AMW ## 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 20061022021449A](https://openairdocs.org/incident/20061022021449A), Oct 22, 2006: Cessna R182, Ames, IA, Substantial damage. (-23) The aircraft was landing at Ames Municipal Airport. The pilot setup to land on runway 31. He noted that the nose gear safe light had not illuminated so… 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.