# NTSB ANC07LA060: Piper PA-18, N3195Z, Talkeetna, AK, July 2, 2007 - Type: NTSB accident investigation - Classification: Accident · No injuries · Limited investigation · Final report - Date: July 1, 2007, 17:45 local (Jul 2, 2007, 01:45 UTC) - Place: Talkeetna, AK - Coordinates: 62.3666666666667, -151.166666666667 - Nearby events: https://openairdocs.org/map.md?lat=62.3667&lon=-151.1667&mi=10 - Phase of flight: [Landing](https://openairdocs.org/ntsb-phases/550) (OpenAirDocs' grouping) - Highest injury: No injuries - Injuries: 1 uninjured - Status: Completed, report March 31, 2008 - Report: Approved by Office Director - NTSB office: Alaska Regional Office - Parties: FAA-AL-ANC FDSO 03 - NTSB case key (mKey): 66141 - NTSB case page: https://web.ntsb.gov/investigations/?ntsbnumber=ANC07LA060 - NTSB report (PDF, downloads): https://data.ntsb.gov/carol-repgen/api/Aviation/ReportMain/GenerateNewestReport/66141/pdf - Page: https://openairdocs.org/ntsb/ANC07LA060 ## Probable cause A fracture and collapse of the main landing gear. Contributing to the accident was an inadequate annual inspection by other maintenance personnel, and corrosion. ## Sequence of events In NTSB's coding before 2008 (https://www.ntsb.gov/GILS/Documents/codman.pdf). - Airframe/component/system failure/malfunction, landing - roll - maintenance,annual inspection - inadequate, other maintenance personnel (contributing factor) - landing gear,main gear shock absorbing strut - fractured (cause) - landing gear,main gear shock absorbing strut - corroded (contributing factor) - Loss of control - on ground/water, landing - roll - landing gear,main gear attachment - collapsed - On ground/water encounter with terrain/water, landing - roll - terrain condition - grass ## Analysis The private pilot was landing a tundra tire-equipped airplane on an off-airport grass surface area. As he applied the brakes during the landing roll, the left main landing gear collapsed. The airplane pivoted to the left, and the left wing struck the ground. His inspection of the landing gear revealed that the outboard end of the left main landing gear strut extension was broken through the outer radius of the attaching lug, where it normally would bolt to the axle. In addition, the landing gear safety cable was broken. The airplane was equipped with hydrasorb landing gear shock units, which consist of automotive type oleo struts, combined with light shock cords. Examination of the outboard end of the hydrasorb extension tube revealed a flat fracture surface that was perpendicular to the long axis of the tube. It had extensive evidence of corrosion. The landing gear had been installed since 1977, and the most recent annual inspection of the airplane was about 1 year before the accident. ## Factual narrative On July 1, 2007, about 1745 Alaska daylight time, a tundra tire-equipped Piper PA-18 airplane, N3195Z, sustained substantial damage during the landing roll at a remote airstrip along the Kahiltna River, about 25 miles west-southwest of Talkeetna, Alaska. The airplane was being operated as a visual flight rules (VFR) cross-country personal flight under Title 14, CFR Part 91, when the accident occurred. The airplane was operated by the pilot. The private certificated pilot, the sole occupant, was not injured. Visual meteorological conditions prevailed. The flight originated at the Wolf Lake Airport, Wasilla, Alaska, about 1600, and no flight plan was filed. During a telephone conversation with the National Transportation Safety Board (NTSB) investigator-in-charge (IIC), on July 2, the pilot reported that he was landing on a grass surface area that was oriented north/south. The area was about 800 feet long, and about 50 feet wide, and he was landing toward the south. He said that during the landing roll, as he applied the brakes, the left main landing gear collapsed. The airplane pivoted to the left, and the left wing struck the ground. His inspection of the landing gear revealed the shock strut and the safety cable were broken. The pilot said he did not think the landing was in anyway hard, and the wind conditions were about 180 degrees at 8 knots. On July 6, the owner of a maintenance facility reported that the airplane received structural damage to the left wing and both wing spars. The airplane was equipped with hydrasorb landing gear shock units, which consist of automotive type oleo struts, combined with light shock cords. The outboard end of the hydrasorb has an extension tube that is normally installed between the wheel axle and the hydrasorb unit. In addition, the landing gear had upper and lower safety cables. The safety cables limit the upward travel of the wheel if a strut unit should fail. The upper safety cable is attached between the fuselage tubing and the center cabane. The lower safety cable is attached between the main wheel axle and the center cabane. On July 10, the pilot brought the broken left hydrasorb strut extension tube to the NTSB Alaska Regional Office. The outboard end of the tube was fractured through the outer radius of the attaching lug, where it normally would bolt to the axle. Visual examination of the broken tube revealed a flat fracture surface that was perpendicular to the long axis of the tube. It had extensive evidence of rust and pitting. In the Pilot/Operator Aircraft Accident Report (NTSB Form 6120.1) submitted by the pilot, the pilot indicated that the most recent annual inspection was July, 2006, but he did not indicate any airframe total time, or time accrued since the inspection. He did indicate that the main landing gear struts had been installed since 1977. According to FAA aircraft certification staff, the accident airplane does not have a manufacturer's maintenance manual. The military version of the accident airplane, the L-21, did have a maintenance manual. Paragraph 2-85, Inspection of Main Landing Gear, of the L-21 manual states, in part: "a. Examine all attaching nuts and bolts for wear, distortion, and damaged threads. Replace damaged part. b. Inspect all metal parts for cracks, distortion, corrosion, and other damage. Replace parts that are damaged beyond repair. Corroded spots must be sanded down to good metal and coated with primer..." Information about aviation maintenance standards are contained in the FAA's advisory circular, AC 43.13-1B, Acceptable Methods, Techniques, and Practices - Aircraft Inspection and Repair. Chapter 9 of the AC, Aircraft Systems and Components, Section 1, Inspection and Maintenance of Landing Gear, states, in part: "9-2. General Inspection; A thorough inspection of the landing gear involves the entire structure of the gear, including attachment, struts, wheels, brakes... . The manufacturer's inspection procedures should be followed where applicable. 9-4. Fixed gear inspection. Fixed landing gear should be examined regularly for wear, deterioration, corrosion, alignment, and other factors that may cause failure or unsatisfactory operation. During a 100-hour or annual inspection of the fixed gear, the aircraft should be jacked up to relieve the aircraft weight. The gear struts and wheels should be checked for play and corrected... (g) The entire structure of the landing gear should be closely examined for cracks, nicks, cuts, corrosion damage, or any other condition that can cause stress concentrations and eventual failure." Chapter 6, Section 5, Visual Corrosion Inspection Guide for Aircraft, of AC 43.13-1B, states, in part: "6-63. General; This guide provides a general inspection checklist for those parts or surfaces that can be visually inspected without disassembly of the aircraft. 6-68. Wheel wells and landing gear; Inspect wheel well area and landing gear components for damage to exterior finish coating and corrosion. Particular attention should be given to exposed surfaces of struts, oleos, arms, links, and attaching hardware; axle interiors, exposed position indicator switches and other electrical equipment; crevices between stiffeners, ribs, and lower skin surfaces; magnesium wheels, particularly around bolt heads, lugs, and wheel web areas; and exposed rigid tubing at "B" nuts and ferrules under clamps, and tubing identification tapes." ## Aircraft - Registration: [N3195Z](https://openairdocs.org/aircraft/N3195Z), registered now, S/N 18-7191, built 1959 (OpenAirDocs) - Reported make and model: Piper PA-18 - Registry model: [Piper PA-18-150](https://openairdocs.org/model/piper-pa-18-150) (registry code 7101828) (OpenAirDocs) - Registry engine: [Lycoming 0-320 series](https://openairdocs.org/engine/lycoming-0-320-series) (registry code 41508, reciprocating) (OpenAirDocs) - Category: Airplane - Serial number: 18-7191 - Engines: Lycoming O-320-B2B 150 horsepower reciprocating - Damage: Substantial damage - Flight: Personal, Part 91 - Registered owner: Chadwick P. McGrady - Airworthiness certificate: Standard, Normal; Standard, Utility - Last inspection: Annual, July 1, 2006 - Departed: 4AK6, Wasilla, AK - Destination: Talkeetna, AK ## Flight crew As NTSB recorded them. NTSB leaves out names. - Pilot; age 31; injuries: none; private; airplane ratings: single-engine land; medical: class 3, without waivers/limitations; last flight review November 1, 2006; seat: front; flight hours: 500 total, 400 in this make and model, 400 as pilot in command, 100 in the last 90 days, 24 in the last 30 days, 2 in the last 24 hours ## Weather - Conditions: Visual (VMC), Day - Wind: 180° at 8 knots - Visibility: 20 statute miles - Lowest ceiling: 2,000 ft broken - Temperature: 61 °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 20070701014799A](https://openairdocs.org/incident/20070701014799A), Jul 1, 2007: Piper PA18150, Talkeetna, AK, Substantial damage. (-23) Original -23 not saved and expect this document to be amended. 7/27/07. Pilot has not completed NTSB report as of this date. Pilot will get a statement… ## Other investigations on N3195Z (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 ANC70DAG27](https://openairdocs.org/ntsb/ANC70DAG27), Jun 7, 1970: Piper PA-18 (N3195Z), Willow, AK, 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.