# NTSB LAX00LA330: Piper PA-28-161, N6462C, Palo Alto, CA, September 4, 2000 - Type: NTSB accident investigation - Classification: Accident · No injuries · Limited investigation · Final report - Date: September 3, 2000, 18:40 local (Sep 4, 2000, 01:40 UTC) - Place: Palo Alto, CA - Coordinates: 37.4496, -122.099243 (estimated) - Nearby events: https://openairdocs.org/map.md?lat=37.4496&lon=-122.0992&mi=10 - Phase of flight: [Landing](https://openairdocs.org/ntsb-phases/550) (OpenAirDocs' grouping) - Highest injury: No injuries - Injuries: 2 uninjured - Status: Completed, report July 17, 2001 - Report: Approved by Office Director - NTSB case key (mKey): 50229 - NTSB case page: https://web.ntsb.gov/investigations/?ntsbnumber=LAX00LA330 - NTSB report (PDF, downloads): https://data.ntsb.gov/carol-repgen/api/Aviation/ReportMain/GenerateNewestReport/50229/pdf - Page: https://openairdocs.org/ntsb/LAX00LA330 ## Probable cause The failure of maintenance personnel to detect and correct loose attachment fasteners and fretting at the landing gear attachment during maintenance inspections. ## Sequence of events In NTSB's coding before 2008 (https://www.ntsb.gov/GILS/Documents/codman.pdf). - Main gear collapsed, landing - flare/touchdown - landing gear,main gear attachment - loose part/bolt/nut/clamp/etc - landing gear,main gear attachment - elongated - landing gear,main gear attachment - fretted - maintenance,inspection - inadequate, other maintenance personnel (cause) - maintenance,100-hour inspection - inadequate, other maintenance personnel (cause) ## Analysis The pilot reported he landed the rental aircraft 'somewhat hard' and collapsed the left main landing gear of the fixed gear airplane. The landing gear casting is bolted to the aft side of the wing spar with 8 bolts, 4 in a rectangular pattern on the top and 4 in a similar pattern on the bottom. During postaccident examination of the bottom 4 bolts it was determined that 2 were absent and not located in the wing, the bolt head was missing on the third bolt, and the fourth bolt was loose. All 4 of the upper attach bolts were loose. There was fretting at the casting-to-spar interface and the holes were elongated. The 8 bolts on the right main landing gear attachment, which did not fail, were all loose. There are no Airworthiness Directives or Service Bulletins in effect regarding the landing gear to wing spar attachment on this model aircraft. The aircraft manufacturer's Inspection Checklist for the 100-hour inspection instructs maintenance personnel to: 'Inspect gear struts, attachments, torque links and bolts for condition and security.' ## Factual narrative On September 3, 2000, at 1840 hours Pacific daylight time, a Piper PA-28-161, N6462C, was substantially damaged when the left main landing gear collapsed during landing at Palo Alto Airport of Santa Clara County, Palo Alto, California. The private pilot and one passenger were not injured. The personal flight, operated under 14 CFR Part 91 by ZP Aviation, Inc., departed from Monterey, California about 0500. Visual meteorological conditions prevailed and no flight plan was filed. The pilot reported that he landed the rental aircraft "somewhat hard" and collapsed the left main landing gear of the fixed gear airplane. According to the pilot, subsequent inspection of the aircraft revealed pre-existing damage to the bolts that attach the main landing gear to the spar. He reported that the landing gear casting is bolted to the aft side of the spar with 8 bolts; 4 in a rectangular pattern on the top, and 4 in a similar pattern on the bottom. Of the bottom 4 bolts, 2 were absent, the bolt head was missing on the third, and the fourth was loose. All 4 of the upper attach bolts were loose. A mechanic, who inspected the aircraft after the accident, confirmed that the two missing bolts were not found in the wing. He added that there was fretting at the casting-to-spar interface, and that the attachment holes were elongated. He also added that the 8 bolts on the right main landing gear attachment, which did not fail, were all loose. According to an investigator at The New Piper Aircraft Company, there are no Airworthiness Directives or Service Bulletins in effect regarding the landing gear to wing spar attachment on this model aircraft. The Piper Airplane Maintenance Manual for the PA-28-161 airplane, dated February 28, 1995, contains an Inspection Checklist for the 100-hour inspection. In the landing gear group of the checklist, item 16 states to "Inspect gear struts, attachments, torque links and bolts for condition and security." ## Aircraft - Registration: [N6462C](https://openairdocs.org/aircraft/N6462C), registered now, S/N 28-7816426, built 1978 (OpenAirDocs) - Reported make and model: Piper PA-28-161 - Registry model: [Piper PA-28-161](https://openairdocs.org/model/piper-pa-28-161) (registry code 7102803) (OpenAirDocs) - Registry engine: [Lycoming 0-320 series](https://openairdocs.org/engine/lycoming-0-320-series) (registry code 41508, reciprocating) (OpenAirDocs) - Category: Airplane - Serial number: 28-7816426 - Airframe hours: 3769 - Engines: Lycoming O-360-D3A 160 horsepower reciprocating - Damage: Substantial damage - Flight: Personal, Part 91 - Operator: Zp Aviation Inc. - Registered owner: Jerome Hoffman - Airworthiness certificate: Standard, Utility; Standard, Normal - Last inspection: 100 hour, July 17, 2000 - Departed: MRY, MONTEREY, CA - Destination: PAO - Airport: PAO, Palo Alto Apt Of Scc, runway 30, 2,500 × 65 ft, asphalt ## Flight crew As NTSB recorded them. NTSB leaves out names. - Pilot; age 70; private; airplane ratings: single-engine land; instrument ratings: airplane; medical: class 1, valid medical--w/ waivers/lim; seat: left; flight hours: 449 total, 18 in this make and model, 349 as pilot in command, 19 in the last 90 days, 8 in the last 30 days, 2 in the last 24 hours ## Weather - Conditions: Visual (VMC), Day - Wind: 310° at 3 knots - Visibility: 10 statute miles - Lowest ceiling: none - Temperature: 135 °F, dew point 108 °F - Altimeter: 30.00 inHg - Observed at: SJC, 9 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 20000903015099A](https://openairdocs.org/incident/20000903015099A), Sep 3, 2000: Piper PA28161, Palo Alto, CA, No damage. (-23) After landing and taxi to parking pilot observed left main landing gear was severed at the spare and damaged the upper surface of the wing. Upon… ## Other investigations on N6462C (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 MKC79FCQ37](https://openairdocs.org/ntsb/MKC79FCQ37), Jul 26, 1979: Piper PA-28 (N6462C), Halstead, KS, 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.