# NTSB ANC19LA047: Piper PA-22-150, N7236D, Talkeetna, AK, August 29, 2019 - Type: NTSB accident investigation - Classification: Accident · No injuries · Class 3 · Limited · Final report - Date: August 28, 2019, 19:00 local (Aug 29, 2019, 03:00 UTC) - Place: Talkeetna, AK - Coordinates: 62.321388, -150.092773 (estimated) - Nearby events: https://openairdocs.org/map.md?lat=62.3214&lon=-150.0928&mi=10 - Phase of flight: [Landing](https://openairdocs.org/ntsb-phases/550) (OpenAirDocs' grouping) - Defining event: [Landing: Landing gear collapse](https://openairdocs.org/ntsb-events/094) - Highest injury: No injuries - Injuries: 2 uninjured - Status: Completed - Report: Approved by Office Director - Investigation class: Class 3 - NTSB office: Alaska Regional Office - NTSB case key (mKey): 100172 - NTSB case page: https://web.ntsb.gov/investigations/?ntsbnumber=ANC19LA047 - NTSB report (PDF, downloads): https://data.ntsb.gov/carol-repgen/api/Aviation/ReportMain/GenerateNewestReport/100172/pdf - NTSB docket: https://data.ntsb.gov/Docket?ProjectID=100172 - Page: https://openairdocs.org/ntsb/ANC19LA047 ## Probable cause A failure of the aft left weld-on fuselage landing gear fitting due to a poor weld joint. ## Findings NTSB's coded findings; those marked are part of the probable cause. - [Landing gear system: main landing gear attach sec](https://openairdocs.org/ntsb-findings/01023211): Aircraft › Aircraft systems · Failure (probable cause); cases with it: [Piper PA-22-150, 4 cases](https://openairdocs.org/ntsb-findings/01023211/cases.md?model=7102210), [All aircraft, 66 cases](https://openairdocs.org/ntsb-findings/01023211/cases.md) ## Sequence of events The events NTSB coded, in order, by phase of flight. The defining event best describes what happened. - [Landing: Landing gear collapse](https://openairdocs.org/ntsb-events/094) (defining event); cases with it: [Piper PA-22-150, 15 cases](https://openairdocs.org/ntsb-events/094/sequence.md?model=7102210), [All aircraft, 1,787 cases](https://openairdocs.org/ntsb-events/094/sequence.md) ## Analysis While dragging an off-airport landing site, the flight instructor heard an audible "pop" and noticed a partial separation of the left main landing gear. After returning to the departure airport, he conducted a fly by and was told that the left main landing gear was loose. The pilot conducted an emergency landing, which resulted in a ground loop and substantial damage to the fuselage. Postaccident examination revealed that the aft left welded-on fuselage landing gear fitting had separated from the fuselage at the welding point. Examination of the fractured weld surfaces revealed an unacceptable weld filet profile, which included incomplete fusion, a lack of penetration, and gross porosity in the weld deposit. ## Factual narrative On August 29, 2019, at about 1900 Alaska daylight time, a tundra tire and tailwheel-equipped Piper PA-22 airplane, N7236D, sustained substantial damage following a partial separation of the left main landing gear near Talkeetna, Alaska. The certificated flight instructor and certificated private pilot receiving instruction were not injured. The airplane was registered to Christianson Lake Rentals Maintenance LLC and operated by Alaska Floats and Skis, under the provisions of Title 14 Code of Federal Regulations Part 91 when the accident occurred. Visual meteorological conditions prevailed, and a company flight plan had been filed. The flight departed Talkeetna Airport (PATK), Talkeetna, Alaska. According to the operator, while dragging an off-airport landing site, the flight instructor heard an audible "pop" and noticed a partial separation of the left main landing gear. They returned to Talkeetna, conducted a fly by and were informed that the left main landing gear was loose. During the ensuing emergency landing, the airplane ground looped and sustained substantial damage to the fuselage. An initial examination of the airplane revealed that the aft left weld-on fuselage landing gear fitting had separated at the weld area from the fuselage. A photographic visual examination of the fractured weld surfaces by the National Transportation Safety Board (NTSB) Materials Laboratory revealed an unacceptable weld filet profile, which included incomplete fusion, a lack of penetration, and gross porosity in the weld deposit. The NTSB Materials Laboratory examination report is in the public docket for this accident. The closest weather reporting facility is Talkeetna Airport, (PATK), Talkeetna, Alaska. At 1853, a METAR from PATK was reporting in part: wind, 200° at 4 knots; visibility, 5 statute miles, smoke, haze; sky condition, overcast clouds, 4,600 ft; temperature, 66° F; dew point 45° F; and an altimeter setting of 30.08 inches of mercury. ## Aircraft - Registration: [N7236D](https://openairdocs.org/aircraft/N7236D), registered now, S/N 22-5062, built 1957 (OpenAirDocs) - Reported make and model: Piper PA-22-150 - Registry model: [Piper PA-22-150](https://openairdocs.org/model/piper-pa-22-150) (registry code 7102210) (OpenAirDocs) - Registry engine: [Lycoming 0-320 series](https://openairdocs.org/engine/lycoming-0-320-series) (registry code 41508, reciprocating) (OpenAirDocs) - Category: Airplane - Serial number: 22-5062 - Year built: 1957 - Airframe hours: 3836.6 - Engines: Lycoming O-320 SERIES 150 horsepower reciprocating - Damage: Substantial damage - Flight: Instructional, Part 91 - Operator: Alaska Floats and Skis - Registered owner: Christianson Lake Rentals Maintenance Ll - Airworthiness certificate: Standard, Normal - Last inspection: Continuous airworthiness, July 23, 2019 - Departed: TKA, Talkeetna, AK - Destination: TKA, Talkeetna, AK - Flight plan: Company VFR - Airport: TKA, Talkeetna, runway 19, 3,500 × 75 ft, asphalt - Equipment: None ## Flight crew As NTSB recorded them. NTSB leaves out names. - Pilot; age 23; injuries: none; flight instructor, commercial; airplane ratings: single-engine sea, single-engine land, multi-engine land; instrument ratings: airplane; medical: class 2, without waivers/limitations; last flight review June 20, 2019; seat: right; restraint: 4-point; flight hours: 1,200 total, 200 in this make and model, 2 as pilot in command, 200 in the last 90 days, 60 in the last 30 days, 3 in the last 24 hours - Pilot; age 58; injuries: none; airline transport; airplane ratings: single-engine land; instrument ratings: airplane; medical: unknown; seat: left ## Weather - Conditions: Visual (VMC), Day - Wind: 200° at 4 knots - Visibility: 5 statute miles - Lowest ceiling: 4,600 ft overcast - Temperature: 66 °F, dew point 45 °F - Altimeter: 30.07 inHg - Observed at: PATK ## 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 20190829011649A](https://openairdocs.org/incident/20190829011649A), Aug 29, 2019: Piper PA-22-150, Talkeetna, AK, Substantial damage. On 08-29-2019 at 1751 local time a Piper PA-22 piloted by maverick brady and student roger ditcher while dragging and off airport landing site the pilot heard… ## Other investigations on N7236D (2) 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 NYC68F0193](https://openairdocs.org/ntsb/NYC68F0193), Sep 8, 1967: Piper PA-22 (N7236D), Kingston, NY, substantial damage - [NTSB NYC68D0156](https://openairdocs.org/ntsb/NYC68D0156), Aug 31, 1967: Piper PA-22 (N7236D), New Salem, NY, substantial damage ## Docket (4 files) The files NTSB released with the investigation on April 17, 2020, on NTSB's docket system: https://data.ntsb.gov/Docket?ProjectID=100172. 1.8 MB in all. - Pilot/Operator Aircraft Accident Report, NTSB Form 6120.1 (item 1, .PDF, 550 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40482522&FileExtension=.PDF&FileName=Pilot%2FOperator%20Aircraft%20Accident%20Report,%20NTSB%20Form%206120.1-Master.PDF - Materials Laboratory - Email (item 2, .PDF, 170 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40482523&FileExtension=.PDF&FileName=Materials%20Laboratory%20-%20Email-Master.PDF - Photos (item 3, .PDF, 993 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40482524&FileExtension=.PDF&FileName=Photos-Master.PDF - Damage Determination (item 4, .PDF, 136 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40482525&FileExtension=.PDF&FileName=Damage%20Determination-Master.PDF 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.