# NTSB ANC21LA030: Beech C-99, N991AK, Chignik Lagoon, AK, April 16, 2021 - Type: NTSB accident investigation - Classification: Accident · No injuries · Class 4 · Limited · Final report - Date: April 16, 2021, 10:10 local (18:10 UTC) - Place: Chignik Lagoon, AK · KCL - Coordinates: 56.31084, -158.5348 (estimated) - Nearby events: https://openairdocs.org/map.md?lat=56.3108&lon=-158.5348&mi=10 - Phase of flight: [Landing](https://openairdocs.org/ntsb-phases/550) (OpenAirDocs' grouping) - Defining event: [Landing-landing roll: Collision with terr/obj (non-CFIT) ](https://openairdocs.org/ntsb-events/470) - Highest injury: No injuries - Injuries: 9 uninjured - Status: Completed - Report: Approved by Office Director - Investigation class: Class 4 - Basic report with no Prelim publish - NTSB office: Alaska Regional Office - Parties: FAA - NTSB case key (mKey): 102941 - NTSB case page: https://web.ntsb.gov/investigations/?ntsbnumber=ANC21LA030 - NTSB report (PDF, downloads): https://data.ntsb.gov/carol-repgen/api/Aviation/ReportMain/GenerateNewestReport/102941/pdf - NTSB docket: https://data.ntsb.gov/Docket?ProjectID=102941 - Page: https://openairdocs.org/ntsb/ANC21LA030 ## Probable cause The pilot’s failure to visually inspect the runway condition before landing, which resulted in a collision with an ice chunk and main landing gear separation during landing. ## Findings NTSB's coded findings; those marked are part of the probable cause. - [Inspection](https://openairdocs.org/ntsb-findings/02061500): Personnel issues › Task performance · Pilot (probable cause); cases with it: [Beech C-99, 1 case](https://openairdocs.org/ntsb-findings/02061500/cases.md?model=1154006), [All aircraft, 29 cases](https://openairdocs.org/ntsb-findings/02061500/cases.md) - [Info processing/decision: decision making/judgment](https://openairdocs.org/ntsb-findings/02041520): Personnel issues › Action/decision · Pilot (probable cause); cases with it: [Beech C-99, 2 cases](https://openairdocs.org/ntsb-findings/02041520/cases.md?model=1154006), [All aircraft, 3,098 cases](https://openairdocs.org/ntsb-findings/02041520/cases.md) - [Info processing/decision: expectation/assumption](https://openairdocs.org/ntsb-findings/02041525): Personnel issues › Action/decision · Pilot (probable cause); cases with it: [Beech C-99, 2 cases](https://openairdocs.org/ntsb-findings/02041525/cases.md?model=1154006), [All aircraft, 51 cases](https://openairdocs.org/ntsb-findings/02041525/cases.md) - [Object/animal/substance: snow/ice](https://openairdocs.org/ntsb-findings/03022060): Environmental issues › Physical environment · Effect on equipment; cases with it: [Beech C-99, 1 case](https://openairdocs.org/ntsb-findings/03022060/cases.md?model=1154006), [All aircraft, 67 cases](https://openairdocs.org/ntsb-findings/03022060/cases.md) ## Sequence of events The events NTSB coded, in order, by phase of flight. The defining event best describes what happened. - [Landing-landing roll: Collision with terr/obj (non-CFIT) ](https://openairdocs.org/ntsb-events/470) (defining event); cases with it: [Beech C-99, 5 cases](https://openairdocs.org/ntsb-events/470/sequence.md?model=1154006), [All aircraft, 10,189 cases](https://openairdocs.org/ntsb-events/470/sequence.md) - [Landing-landing roll: Part(s) separation from AC](https://openairdocs.org/ntsb-events/338); cases with it: [Beech C-99, 1 case](https://openairdocs.org/ntsb-events/338/sequence.md?model=1154006), [All aircraft, 563 cases](https://openairdocs.org/ntsb-events/338/sequence.md) - [Landing-landing roll: Nose over/nose down](https://openairdocs.org/ntsb-events/096); cases with it: [Beech C-99, 2 cases](https://openairdocs.org/ntsb-events/096/sequence.md?model=1154006), [All aircraft, 2,287 cases](https://openairdocs.org/ntsb-events/096/sequence.md) ## Analysis The pilot reported that, during final approach to land, he noticed a road grader operating on the far end of the runway. He made a radio transmission stating that the flight was 4 miles out on final approach and observed the road grader pull over at the opposite end of the airport and park. Believing that the operator of the road grader heard his call and parked, he proceeded with a normal approach and landing. After touchdown, he applied reverse with moderate braking. When the airplane was fully out of reverse and had slowed to about 35 mph, he noticed a large piece of foreign object debris (FOD) on the runway centerline. The FOD appeared to be about 18 inches wide and about 12 inches tall. He veered to the left in an effort to straddle the FOD with main landing gear. Subsequently, the right main landing gear struck the FOD, the right main landing gear collapsed, and the airplane slid about 75 ft down the runway centerline before coming to a stop. The airplane sustained substantial damage to the right wing. A postaccident inspection revealed that the FOD was a chunk of ice. The pilot also learned that the road grader was not equipped with an aircraft radio. The pilot reported no preaccident mechanical failures or malfunctions with the airplane that would have precluded normal operation. The Federal Aviation Administration Supplement Alaska for the applicable airport under AIRPORT REMARKS states in part: Unattended. Rwy condition not monitored, recommend visual inspection prior to using. Seabirds on and invof arpt. Vehicle and pedestrians frequently use numerous roads and trails that cross rwy. Loose rocks on rwy sfc up to 6". Rwy 04–22 sfc contains numerous rocks and puddles. Several roads and trails cross Rwy 04–22. Rwy 04 thlds marked with orange reflective cones. ## Aircraft - Registration: [N991AK](https://openairdocs.org/aircraft/N991AK), registered now, S/N U-189, built 1982 (OpenAirDocs) - Reported make and model: BEECH C-99 - Registry model: [Beech C-99](https://openairdocs.org/model/beech-c-99) (registry code 1154006) (OpenAirDocs) - Registry engine: [Pratt & Whitney Canada PT6A-36](https://openairdocs.org/engine/pratt-whitney-canada-pt6a-36) (registry code 52253, turbo-prop) (OpenAirDocs) - Category: Airplane - Serial number: U-189 - Year built: 1982 - Airframe hours: 27917.9 - Engines: P&W CANADA PT6A-36 783 horsepower turbo prop; P&W CANADA PT6A-36 783 horsepower turbo prop - Damage: Substantial damage - Flight: Business, Part 135 - Operator: Lake Clark Air Inc - Registered owner: Lake Clark Air Inc - Airworthiness certificate: Standard, Normal - Last inspection: 100 hour, April 8, 2021 - Departed: MRI, Anchorage, AK - Destination: Same as departure - Flight plan: Company VFR - Airport: KCL, Chignik Lagoon, runway 22, 2,200 × 90 ft, gravel - Equipment: ADS-B ## Flight crew As NTSB recorded them. NTSB leaves out names. - Pilot; age 54; injuries: none; commercial; airplane ratings: single-engine sea, single-engine land, multi-engine land; instrument ratings: airplane; medical: class 2, without waivers/limitations; last flight review January 9, 2021; seat: left; restraint: lap only; flight hours: 13,724 total, 3,020 in this make and model, 13,624 as pilot in command, 341 in the last 90 days, 139 in the last 30 days, 7 in the last 24 hours ## Weather - Conditions: Visual (VMC), Day - Wind: calm - Visibility: 10 statute miles - Lowest ceiling: none - Temperature: 37 °F, dew point 30 °F - Altimeter: 30.49 inHg - Observed at: PAJC, 5 nm away - METAR: PAJC 161757Z AUTO 00000KT 10SM OVC050 03/M01 A3049 RMK AO2 SLP326 T00281011 10028 20000 51015 ## 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 20210416005319A](https://openairdocs.org/incident/20210416005319A), Apr 16, 2021: Beech C-99, Chignik Lagoon, AK, Substantial damage. Pilot landed on runway 22, did not notice anything unusual on final. During the roll out and initiation of thrust reversal, pilot's attention was divided… ## Docket (3 files) The files NTSB released with the investigation on September 20, 2021, on NTSB's docket system: https://data.ntsb.gov/Docket?ProjectID=102941. 7.7 MB in all. - Pilot/operator aircraft accident report, NTSB form 6120.1 (item 1, PDF, 10 pages, 6.4 MB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=12234264&FileExtension=pdf&FileName=6120_Redacted-Rel.pdf - Chart supplement Alaska (item 2, PDF, 1 page, 64 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=12234437&FileExtension=pdf&FileName=AK_79_22APR2021-Rel.pdf - Accident pictures (item 3, PDF, 3 pages, 1.2 MB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=12234274&FileExtension=pdf&FileName=Accident%20Pictures-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.