# NTSB SEA00LA032: Cessna 140, N2739N, Helena, MT, December 15, 1999 - Type: NTSB accident investigation - Classification: Accident · No injuries · Limited investigation · Final report - Date: December 15, 1999, 15:30 local (22:30 UTC) - Place: Helena, MT - Coordinates: 46.529342, -112.209983 (estimated) - Nearby events: https://openairdocs.org/map.md?lat=46.5293&lon=-112.2100&mi=10 - Phase of flight: [Landing](https://openairdocs.org/ntsb-phases/550) (OpenAirDocs' grouping) - Highest injury: No injuries - Injuries: 1 uninjured - Status: Completed, report May 17, 2001 - Report: Approved by Office Director - NTSB case key (mKey): 48527 - NTSB case page: https://web.ntsb.gov/investigations/?ntsbnumber=SEA00LA032 - NTSB report (PDF, downloads): https://data.ntsb.gov/carol-repgen/api/Aviation/ReportMain/GenerateNewestReport/48527/pdf - Page: https://openairdocs.org/ntsb/SEA00LA032 ## Probable cause Separation of the left main landing gear. Factors include inadequate preflight inspection by the pilot, and inadequate inspection at the time of annual inspection by maintenance personnel. ## Analysis The pilot stated that on his second touch-and-go landing at the airstrip, about half way down the runway, the left wheel separated and the airplane nosed over. FAA inspectors observed that the left wheel and gear extension had separated from the left main landing gear leg and were found off the runway on the left side. Surface tracks indicated that the airplane had been tracking along the centerline of the runway, and that the airplane had continued to track down the centerline for an additional 30 yards before it nosed over. The four left main landing gear extension attachment bolts were inspected by the NTSB's material laboratory. Examination revealed that all four bolts were bent through the shank portion; however, none of the bolts were separated. Additionally, the threads in each bolt were scraped on the convex side of the bend, as if from sliding out of the bolt hole. Three of the four bolts exhibited what appeared to be stripped threads of their corresponding nuts in their thread grooves. No evidence was found of the presence of a nut on the fourth bolt. Records revealed that the airplane had received an annual inspection on November 11, 1999, and it had accumulated seven hours of operation since that inspection. ## Factual narrative On December 15, 1999, approximately 1530 mountain standard time, a Cessna 140, N2739N, sustained substantial damage when it nosed over during landing roll at Silver City airstrip, about 18 miles northwest of Helena, Montana. The private pilot, the sole occupant, was uninjured. Visual meteorological conditions prevailed at the time of the accident. No flight plan was filed for the flight, which had originated at Helena, about 1500. The ELT actuated, but was shut off by the pilot immediately after the accident. The pilot stated that on his second touch-and-go landing at the airstrip, about half way down the runway, the left wheel separated and the airplane nosed over. FAA inspectors observed that the left wheel and gear extension had separated from the left main landing gear leg and were found off the runway on the left side. Surface tracks indicated that the airplane had been tracking along the centerline of the runway, and that the airplane had continued to track down the centerline for an additional 30 yards before it nosed over. The four left main landing gear extension attachment bolts were inspected by the NTSB's material laboratory. Examination revealed that all four bolts were bent through the shank portion; however, none of the bolts were separated. Additionally, the threads in each bolt were scraped on the convex side of the bend, as if from sliding out of the bolt hole. Three of the four bolts exhibited what appeared to be stripped threads of their corresponding nuts in their thread grooves. No evidence was found of the presence of a nut on the fourth bolt. See attached materials laboratory factual report for photographs. Records revealed that the airplane had received an annual inspection on November 11, 1999, and it had accumulated seven hours of operation since that inspection. ## Sequence of events In NTSB's coding before 2008 (https://www.ntsb.gov/GILS/Documents/codman.pdf). - Airframe/component/system failure/malfunction, landing - landing gear,main gear - separation (cause) - maintenance,annual inspection - inadequate, other maintenance personnel (contributing factor) - aircraft preflight - inadequate, pilot in command (contributing factor) - Nose over, landing - roll ## Aircraft - Registration: [N2739N](https://openairdocs.org/deregistered/N2739N-2018-01-17), registration cancelled 2018-01-17, S/N 12997, built 1947 (OpenAirDocs) - Reported make and model: Cessna 140 - Registry model: [Cessna 140](https://openairdocs.org/model/cessna-140) (registry code 2071602) (OpenAirDocs) - Registry engine: [Continental C85 series](https://openairdocs.org/engine/continental-c85-series) (registry code 17008, reciprocating) (OpenAirDocs) - Category: Airplane - Serial number: 12997 - Airframe hours: 2341 - Engines: Continental C-85-12 85 horsepower reciprocating - Damage: Substantial damage - Flight: Personal, Part 91 - Registered owner: John A Padilla - Airworthiness certificate: Standard, Normal - Last inspection: Annual, November 11, 1999, 7 hours before - Departed: HLN, HELENA, MT - Airport: MT18, Silver City, runway 8, 4,000 × 85 ft, grass/turf ## Flight crew As NTSB recorded them. NTSB leaves out names. - Pilot; age 54; private; airplane ratings: single-engine land; medical: class 3, expired; seat: left; flight hours: 216 total, 8 in this make and model, 169 as pilot in command, 10 in the last 90 days, 8 in the last 30 days, 2 in the last 24 hours ## Weather - Conditions: Visual (VMC), Day - Wind: calm - Visibility: 20 statute miles - Lowest ceiling: none - Temperature: 30 °F ## 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 19991215044409A](https://openairdocs.org/incident/19991215044409A), Dec 15, 1999: Cessna 140, Helena, MT, No damage. (-23) On December 15, 1999, at approx. 1530 MST, a Cessna 140, N2739N sustained substantial damage when it nosed over during landing roll at the silver city… From the NTSB's public API. Aircraft are matched to registry aircraft by N-number and event date; 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.