# NTSB ANC04LA051: Piper PA-18, N2521S, Kasilof, AK, May 6, 2004 - Type: NTSB accident investigation - Classification: Accident · No injuries · Limited investigation · Final report - Date: May 6, 2004, 11:30 local (19:30 UTC) - Place: Kasilof, AK - Coordinates: 60.799999, -152.666671 - Nearby events: https://openairdocs.org/map.md?lat=60.8000&lon=-152.6667&mi=10 - Phase of flight: [Landing](https://openairdocs.org/ntsb-phases/550) (OpenAirDocs' grouping) - Highest injury: No injuries - Injuries: 1 uninjured - Status: Completed, report January 24, 2005 - Report: Approved by Office Director - NTSB office: Alaska Regional Office - Parties: Federal Aviation Administration - NTSB case key (mKey): 59286 - NTSB case page: https://web.ntsb.gov/investigations/?ntsbnumber=ANC04LA051 - NTSB report (PDF, downloads): https://data.ntsb.gov/carol-repgen/api/Aviation/ReportMain/GenerateNewestReport/59286/pdf - Page: https://openairdocs.org/ntsb/ANC04LA051 ## Probable cause The pilot's inadequate compensation for wind conditions while landing, which resulted in an undershoot and an in-flight collision with terrain. Factors associated with the accident were a downdraft, and an embankment. ## Sequence of events In NTSB's coding before 2008 (https://www.ntsb.gov/GILS/Documents/codman.pdf). - Undershoot, landing - flare/touchdown - weather condition - downdraft (contributing factor) - compensation for wind conditions - inadequate, pilot in command (cause) - In flight collision with terrain/water, landing - flare/touchdown - terrain condition - dirt bank/rising embankment (contributing factor) - Gear collapsed, landing - flare/touchdown ## Analysis The solo private certificated pilot was landing on a remote sand-covered beach. He said he flew over the beach, and observed a small creek at the approach end of his intended landing site. He reported that during the landing flare, he encountered a slight downdraft, and he inadvertently allowed the airplane to descend below the intended glide path. He said that the main wheels struck the bank of the creek, and the right main landing gear collapsed. Following the landing gear collapse, the right wing struck the beach. The airplane sustained structural damage to the right wing, both right lift struts, and fuselage. The pilot said that there were no preaccident mechanical anomalies noted with the airplane. ## Factual narrative On May 6, 2004, about 1130 Alaska daylight time, a tundra tire-equipped Piper PA-18 airplane, N2521S, sustained substantial damage when the right main landing gear collapsed and the right wing struck the ground while landing, about 35 miles west of Kasilof, 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 solo private certificated pilot was not injured. Visual meteorological conditions prevailed, and no flight plan was filed. The flight originated about 1000, from the Merrill Field Airport, Anchorage, Alaska. During a telephone conversation with the NTSB investigator-in-charge on May 7, the pilot reported he was landing on a remote sand-covered beach site, commonly known as Polly Creek. He said he flew over the beach, and observed a small creek at the approach end of his intended landing site. The pilot reported that during the landing flare, he encountered a slight downdraft, and he inadvertently allowed the airplane to descend below the intended glide path. He said that the main wheels struck the bank of the creek, and the right main landing gear collapsed. Following the landing gear collapse, the right wing struck the beach. The airplane sustained structural damage to the right wing, both right lift struts, and fuselage. The pilot said that there were no preaccident mechanical anomalies noted with the airplane. ## Aircraft - Registration: [N2521S](https://openairdocs.org/aircraft/N2521S), registered now, S/N 18-7909152, built 1979 (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: 18-7909152 - Airframe hours: 1744.1 - Engines: Lycoming O-320-A2B 150 horsepower reciprocating - Damage: Substantial damage - Flight: Personal, Part 91 - Registered owner: Jan K. Sieberts - Airworthiness certificate: Standard, Normal - Last inspection: Annual, December 19, 2003, 21 hours before - Departed: MRI, ANCHORAGE, AK - Destination: Kasilof, AK ## Flight crew As NTSB recorded them. NTSB leaves out names. - Pilot; age 61; injuries: none; private; airplane ratings: single-engine land, single-engine sea; medical: class 3, valid medical--w/ waivers/lim; last flight review September 1, 2003; seat: front; flight hours: 703 total, 694 in this make and model, 641 as pilot in command, 6 in the last 90 days, 6 in the last 30 days, 2 in the last 24 hours ## Weather - Conditions: Visual (VMC), Day - Wind: 360° at 5 knots, gusting 10 - Visibility: 50 statute miles - Temperature: 50 °F - Altimeter: 29.39 inHg ## 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 20040506009589A](https://openairdocs.org/incident/20040506009589A), May 6, 2004: Piper PA18150, Kasilof, AK, Minor damage. (-23) On may 6, 2004, Mr. Sieberts, pilot-in-command, departed merrill field (mri) in N2521S, a Piper super cub (PA-18) enroute to polly creek (off airport… 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.