# NTSB ANC23LA050: Aviat A-1B, N460JC, Matanuska Glacier, AK, July 13, 2023 - Type: NTSB accident investigation - Classification: Accident · No injuries · Class 4 · Limited · Final report - Date: July 13, 2023, 15:30 local (23:30 UTC) - Place: Matanuska Glacier, AK · "A gravel Super Cub airstrip exists about ¼ mile from the hut. It is a one-way only landing and take-off and requires tundra tires but it is in an excellent shape. From the strip head uphill on the tundra benches for 700 feet to find the hut. In winter a landing can be made on Scandinavian Glacier on skis, 5 minute ski form the hut." (mtnclubak.org) - Coordinates: 61.589432, -147.47834 (estimated) - Nearby events: https://openairdocs.org/map.md?lat=61.5894&lon=-147.4783&mi=10 - Phase of flight: [Initial climb](https://openairdocs.org/ntsb-phases/350) (OpenAirDocs' grouping) - Defining event: [Initial climb: Collision with terr/obj (non-CFIT) ](https://openairdocs.org/ntsb-events/470) - 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 - Parties: Federal Aviation Administration (FAA) - NTSB case key (mKey): 192639 - NTSB case page: https://web.ntsb.gov/investigations/?ntsbnumber=ANC23LA050 - NTSB report (PDF, downloads): https://data.ntsb.gov/carol-repgen/api/Aviation/ReportMain/GenerateNewestReport/192639/pdf - NTSB docket: https://data.ntsb.gov/Docket?ProjectID=192639 - Page: https://openairdocs.org/ntsb/ANC23LA050 ## Probable cause The airplane’s encounter with downdrafts resulting in decreased performance insufficient to outclimb rising terrain. ## 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); cases with it: [Aviat A-1B, 9 cases](https://openairdocs.org/ntsb-findings/02041520/cases.md?model=2210406), [All aircraft, 3,098 cases](https://openairdocs.org/ntsb-findings/02041520/cases.md) - [Planning/preparation: flight planning/navigation](https://openairdocs.org/ntsb-findings/02061025): Personnel issues › Task performance · Pilot (probable cause); cases with it: [Aviat A-1B, 2 cases](https://openairdocs.org/ntsb-findings/02061025/cases.md?model=2210406), [All aircraft, 179 cases](https://openairdocs.org/ntsb-findings/02061025/cases.md) - [Performance/control parameters: climb rate](https://openairdocs.org/ntsb-findings/01062035): Aircraft › Aircraft oper/perf/capability · Not attained/maintained; cases with it: [Aviat A-1B, 1 case](https://openairdocs.org/ntsb-findings/01062035/cases.md?model=2210406), [All aircraft, 265 cases](https://openairdocs.org/ntsb-findings/01062035/cases.md) - [Wind: downdraft](https://openairdocs.org/ntsb-findings/03034035): Environmental issues › Conditions/weather/phenomena · Contributed to outcome; cases with it: [Aviat A-1B, 4 cases](https://openairdocs.org/ntsb-findings/03034035/cases.md?model=2210406), [All aircraft, 178 cases](https://openairdocs.org/ntsb-findings/03034035/cases.md) ## Sequence of events The events NTSB coded, in order, by phase of flight. The defining event best describes what happened. - [Initial climb: Collision with terr/obj (non-CFIT) ](https://openairdocs.org/ntsb-events/470) (defining event); cases with it: [Aviat A-1B, 23 cases](https://openairdocs.org/ntsb-events/470/sequence.md?model=2210406), [All aircraft, 10,189 cases](https://openairdocs.org/ntsb-events/470/sequence.md) - [Initial climb: Off-field or emergency landing](https://openairdocs.org/ntsb-events/440); cases with it: [Aviat A-1B, 5 cases](https://openairdocs.org/ntsb-events/440/sequence.md?model=2210406), [All aircraft, 3,365 cases](https://openairdocs.org/ntsb-events/440/sequence.md) - [Initial climb: Other weather encounter](https://openairdocs.org/ntsb-events/400); cases with it: [Aviat A-1B, 5 cases](https://openairdocs.org/ntsb-events/400/sequence.md?model=2210406), [All aircraft, 1,127 cases](https://openairdocs.org/ntsb-events/400/sequence.md) ## Analysis The pilot reported he encountered downdrafts during landing on a remote gravel airstrip near a glacial base camp known for downdrafts and mountain rotors. He elected to depart the airstrip into rising terrain due to more favorable winds. During initial climb out the pilot reported the airplane encountered more downdrafts than expected. Unable to outclimb rising terrain, the pilot performed a forced landing in an area of rough, rock-covered terrain, and during landing the airplane sustained substantial damage to the wings and fuselage. The pilot reported that there were no pre-accident mechanical malfunctions or failures with the airplane that would have precluded normal operation. ## Aircraft - Registration: [N460JC](https://openairdocs.org/aircraft/N460JC), registered now, S/N 2343, built 2006 (OpenAirDocs) - Reported make and model: AVIAT AIRCRAFT INC A-1B - Registry model: [Aviat A-1B](https://openairdocs.org/model/aviat-a-1b) (registry code 2210406) (OpenAirDocs) - Registry engine: [Lycoming O-360-A1P](https://openairdocs.org/engine/lycoming-o-360-a1p) (registry code 42259, reciprocating) (OpenAirDocs) - Category: Airplane - Serial number: 2343 - Year built: 2006 - Engines: Lycoming O-360-A1P 180 hp reciprocating - Damage: Substantial damage - Flight: Personal, Part 91 - Airworthiness certificate: Standard, Normal - Departed: PAMR, Anchorage, AK - Destination: PAMR, Anchorage, AK - Airport: Scandinavian Peaks Hut Airstrip - Equipment: Stall warning system, ADS-B, Handheld GPS ## Flight crew As NTSB recorded them. NTSB leaves out names. - Pilot; age 37; injuries: none; flight instructor, military, airline transport; airplane ratings: single-engine land, multi-engine land; instrument ratings: airplane; medical: class 1, without waivers/limitations; seat: front; restraint: 5-point; flight hours: 10,020 total, 898 in this make and model, 3,266 as pilot in command, 261 in the last 90 days, 44 in the last 30 days, 3 in the last 24 hours ## Weather - Conditions: Visual (VMC), Day - Wind: 110° at 5 knots - Visibility: 10 statute miles - Temperature: 73 °F, dew point 55 °F - Altimeter: 30.10 inHg - Observed at: PAAQ, 46 nm away - METAR: PAAQ 132253Z 11005KT 10SM FEW035 SCT075 23/13 A3010 RMK AO2 SLP192 T02280133 ## 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 20230713010959A](https://openairdocs.org/incident/20230713010959A), Jul 13, 2023: Aviat Aircraft Inc A-1B, Chickaloon, AK, Substantial damage. Accident occured at a remote airstrip located off the matanuska glacier. Pilot chose to make a takeoff toward rising terrain due to prevailing wind conditions… ## Docket (2 files) The files NTSB released with the investigation on February 1, 2024, on NTSB's docket system: https://data.ntsb.gov/Docket?ProjectID=192639. 7.0 MB in all. - Pilot/operator aircraft accident report, NTSB form 6120.1 (item 1, PDF, 11 pages, 4.7 MB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=16200642&FileExtension=pdf&FileName=NTSB%206120-Rel.pdf - Photos (item 2, PDF, 4 pages, 2.3 MB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=16201201&FileExtension=pdf&FileName=ANC23LA050%20Photos-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.