# NTSB ANC21LA027: Beech A36, N1820L, Port Alsworth, AK, March 20, 2021 - Type: NTSB accident investigation - Classification: Accident · No injuries · Class 4 · Limited · Final report - Date: March 19, 2021, 16:15 local (Mar 20, 2021, 00:15 UTC) - Place: Port Alsworth, AK - Coordinates: 60.204333, -154.31887 - Nearby events: https://openairdocs.org/map.md?lat=60.2043&lon=-154.3189&mi=10 - Phase of flight: [Landing](https://openairdocs.org/ntsb-phases/550) (OpenAirDocs' grouping) - Defining event: [Landing: Landing area undershoot](https://openairdocs.org/ntsb-events/370) - Highest injury: No injuries - Injuries: 2 uninjured - Status: Completed - Report: Approved by Office Director - Investigation class: Class 4 - Basic report with no Prelim publish - NTSB office: Alaska Regional Office - NTSB case key (mKey): 102805 - NTSB case page: https://web.ntsb.gov/investigations/?ntsbnumber=ANC21LA027 - NTSB report (PDF, downloads): https://data.ntsb.gov/carol-repgen/api/Aviation/ReportMain/GenerateNewestReport/102805/pdf - NTSB docket: https://data.ntsb.gov/Docket?ProjectID=102805 - Page: https://openairdocs.org/ntsb/ANC21LA027 ## Probable cause The pilot's misidentification of the airport’s active runway, which resulted in an off runway landing and a collision with a snow berm. Contributing to the accident was the runway’s lack of identifying markings. ## Findings NTSB's coded findings; those marked are part of the probable cause. - [Info processing/decision: decision making/judgment](https://openairdocs.org/ntsb-findings/02041520): Personnel issues › Action/decision · Pilot (probable cause) - [Runway/land/takeoff/taxi surface: snow/slush/ice covered surface](https://openairdocs.org/ntsb-findings/03023015): Environmental issues › Physical environment · Awareness of condition ## Analysis According to the pilot, during the approach to land on a plowed- snow-covered runway, he selected a touchdown point near, what he had identified as, the runway threshold. On short final a pilot-rated passenger seated in the right front seat recommended adding power. The pilot assumed this was to “cushion” the landing not realizing he was landing short of the runway’s plowed surface. Subsequently, the airplane touchdown in an area of unplowed snow, impacted a snow berm, and the nosewheel collapsed. The airplane sustained substantial damage to the fuselage. The pilot reported no preaccident mechanical failures or malfunctions that would have precluded normal operations. In the recommendation section of the NTSB Accident/Incident Reporting Form 6120.1, the pilot stated that the accident may have been prevented if there were clear runway threshold markings to define the runway’s plowed surface. According to the operator, cones are normally used to identify the runway threshold; however, they had been removed due to ongoing snow removal operations on the day of the accident. ## Sequence of events The events NTSB coded, in order, by phase of flight. The defining event best describes what happened. - [Landing: Landing area undershoot](https://openairdocs.org/ntsb-events/370) (defining event) ## Aircraft - Registration: [N1820L](https://openairdocs.org/aircraft/N1820L), registered now, S/N E-843, built 1976 (OpenAirDocs) - Reported make and model: BEECH A36 - Registry model: [Beech A36](https://openairdocs.org/model/beech-a36) (registry code 1151604) (OpenAirDocs) - Registry engine: [Continental IO-520 series](https://openairdocs.org/engine/continental-io-520-series) (registry code 17032, reciprocating) (OpenAirDocs) - Category: Airplane - Serial number: E-843 - Year built: 1976 - Airframe hours: 26135.6 - Engines: CONT MOTOR IO-550B 285 horsepower reciprocating - Damage: Substantial damage - Flight: Business, Part 91 - Operator: Lake Clark Air - Registered owner: Alsworth Glen R - Airworthiness certificate: Standard, Normal - Last inspection: 100 hour, December 23, 2020 - Departed: MRI, Anchorage, AK - Destination: Same as departure - Flight plan: Company VFR - Airport: TPO, Port Alsworth, runway 06L, 3,000 × 100 ft, snow - Equipment: Stall warning system ## Flight crew As NTSB recorded them. NTSB leaves out names. - Pilot; age 35; injuries: none; commercial; airplane ratings: single-engine land, multi-engine land; instrument ratings: airplane; medical: class 1, without waivers/limitations; last flight review May 7, 2020; seat: left; restraint: 3-point; flight hours: 1,325 total, 4 in this make and model, 1,225 as pilot in command, 4 in the last 90 days, 4 in the last 30 days ## Weather - Conditions: Visual (VMC), Day - Wind: 70° at 6 knots - Visibility: 40 statute miles - Lowest ceiling: none - Temperature: 28 °F, dew point 16 °F - Altimeter: 29.54 inHg - Observed at: PALJ - METAR: PALJ 192255Z 07006KT 40SM FEW100 M02/M09 A2954 RMK EST PASS OPEN NOSPECI ## 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 20210319002169A](https://openairdocs.org/incident/20210319002169A), Mar 19, 2021: Beech A36, Port Alsworth, AK, Substantial damage. After a preflight inspection, and obtaining a weather briefting, the pilot took off at approximately 1 :15 pm from pamr with the Destination being tpo.… ## Other investigations on N1820L (3) 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 ANC13CA038](https://openairdocs.org/ntsb/ANC13CA038), Apr 15, 2013: Beech A36 (N1820L), Port Alsworth, AK, substantial damage. Probable cause: The failure of the left main landing gear retraction brace assembly, resulting in the collapse of the left main landing gear. - [NTSB ANC01LA010](https://openairdocs.org/ntsb/ANC01LA010), Oct 12, 2000: Beech BE-A36 (N1820L), Nondalton, AK, substantial damage. Probable cause: The pilot's inadvertent retraction of the landing gear during the landing roll. - [NTSB ANC98LA159](https://openairdocs.org/ntsb/ANC98LA159), Sep 26, 1998: Beech A36 (N1820L), New Stuyahok, AK, substantial damage. Probable cause: The pilot's failure to extend the landing gear prior to landing. Factors associated with this accident were the pilot's interference with his normal habit pattern, turbulence, and the crosswind… ## Docket (2 files) The files NTSB released with the investigation on August 20, 2021, on NTSB's docket system: https://data.ntsb.gov/Docket?ProjectID=102805. 7.0 MB in all. - Pilot/operator aircraft accident report, NTSB form 6120.1 (item 1, PDF, 9 pages, 4.1 MB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=12134532&FileExtension=pdf&FileName=6120%20dms_Redacted-Rel.pdf - Photos (item 2, PDF, 2 pages, 2.9 MB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=12135227&FileExtension=pdf&FileName=Photo-Rel.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.