# NTSB ANC02LA052: Grumman G-21, N21A, Northway, AK, June 17, 2002 - Type: NTSB accident investigation - Classification: Accident · No injuries · Limited investigation · Final report - Date: June 17, 2002, 12:04 local (20:04 UTC) - Place: Northway, AK - Coordinates: 61.739097, -148.219528 (estimated) - Nearby events: https://openairdocs.org/map.md?lat=61.7391&lon=-148.2195&mi=10 - Phase of flight: [Landing](https://openairdocs.org/ntsb-phases/550) (OpenAirDocs' grouping) - Highest injury: No injuries - Injuries: 3 uninjured - Status: Completed, report May 30, 2003 - Report: Approved by Office Director - NTSB office: Alaska Regional Office - Parties: Federal Aviation Administration - NTSB case key (mKey): 54972 - NTSB case page: https://web.ntsb.gov/investigations/?ntsbnumber=ANC02LA052 - NTSB report (PDF, downloads): https://data.ntsb.gov/carol-repgen/api/Aviation/ReportMain/GenerateNewestReport/54972/pdf - NTSB docket: https://data.ntsb.gov/Docket?ProjectID=54972 - Page: https://openairdocs.org/ntsb/ANC02LA052 ## Probable cause The pilot's inadequate compensation for wind conditions during the landing roll, which resulted in an inadvertent ground loop/swerve. A factor associated with the accident was a crosswind. ## Sequence of events In NTSB's coding before 2008 (https://www.ntsb.gov/GILS/Documents/codman.pdf). - Loss of control - on ground/water, landing - roll - weather condition - crosswind (contributing factor) - compensation for wind conditions - inadequate, pilot in command (cause) - ground loop/swerve - inadvertent, pilot in command - On ground/water collision with object, landing - roll - object - tree(s) ## Analysis The certificated private pilot reported that while on approach for landing on runway 22, he encountered a strong right crosswind. After touchdown, during the landing roll, a gust of wind lifted the right wing, and the airplane veered to the left. The airplane ultimately departed the left side of the runway, rolled down an embankment, and came to rest in an area that contained trees. The airplane sustained substantial damage to the right wing and right horizontal stabilizer. The pilot reported that there were no preaccident anomalies with the airplane. ## Factual narrative On June 17, 2002, about 1204 Alaska daylight time, an amphibious Grumman Goose G-21 airplane, N21A, sustained substantial damage following a loss of control during the landing roll at the Northway Airport, Northway, Alaska. The airplane was being operated as an instrument flight rules (IFR) cross-country personal flight under Title 14, CFR Part 91, when the accident occurred. The certificated private pilot and the two passengers were not injured. Visual meteorological conditions prevailed, and an IFR flight plan was in effect, but was canceled prior to starting the visual approach for landing. The flight originated at 1101, from the Whitehorse International Airport, Whitehorse, Yukon, Canada. During a telephone conversation with the National Transportation Safety Board investigator-in-charge on June 17, the pilot reported that while on approach for landing on runway 22, he encountered a strong right crosswind. He said that after touchdown, during the landing roll, a gust of wind lifted the right wing, and the airplane veered to the left. The airplane ultimately departed the left side of the runway, rolled down an embankment, and came to rest in an area that contained trees. The airplane sustained substantial damage to the right wing and right horizontal stabilizer. The closest official weather observation station is at the Northway Airport. On June 17, at 1207, about 3 minutes after the accident, a special weather observation was reporting in part: Wind, 310 degrees at 8 knots with gusts to 15 knots, variable 280 degrees to 350 degrees; visibility, 10 statute miles; clouds and sky conditions, clear; temperature, 71 degrees F; dew point, 39 degrees F; altimeter, 29.73 inHg. The pilot reported that there were no preaccident anomalies with the airplane. ## Aircraft - Registration: [N21A](https://openairdocs.org/aircraft/N21A), registered now, S/N B129, built 1946 (OpenAirDocs) - Reported make and model: Grumman G-21 - Registry model: [Grumman G-21A](https://openairdocs.org/model/grumman-g-21a) (registry code 3951204) (OpenAirDocs) - Registry engine: [Amateur-built UNKNOWN ENG](https://openairdocs.org/engine/amateur-built-unknown-eng) (registry code 99999) (OpenAirDocs) - Category: Airplane - Serial number: B129 - Airframe hours: 24176 - Engines: Pratt & Whitney R-985 450 horsepower reciprocating - Damage: Substantial damage - Flight: Personal, Part 91 - Registered owner: Tuthill Corporation - Airworthiness certificate: Standard, Normal - Last inspection: Annual, March 15, 2002, 27 hours before - Departed: CYXY, Whitehorse - Destination: ORT, Northway, AK - Flight plan: IFR - Airport: PAOR, Northway, runway 22, 5,100 × 100 ft, asphalt ## Flight crew As NTSB recorded them. NTSB leaves out names. - Pilot; age 49; injuries: none; private; airplane ratings: multi-engine land, single-engine land, single-engine sea; instrument ratings: airplane; medical: class 3, valid medical--no waivers/lim.; seat: front; flight hours: 1,284 total, 377 in this make and model, 1,176 as pilot in command, 59 in the last 90 days, 53 in the last 30 days, 6 in the last 24 hours ## Weather - Conditions: Visual (VMC), Day - Wind: 310° at 8 knots, gusting 15 - Visibility: 10 statute miles - Lowest ceiling: none - Temperature: 72 °F, dew point 39 °F - Altimeter: 29.72 inHg - Observed at: ORT ## 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 20020617011549A](https://openairdocs.org/incident/20020617011549A), Jun 17, 2002: Grumav G21, Northway, AK, No damage. (.19) On June 17, 2002, about 1204 Alaska daylight time, an amphibious Grumman goose G-21 airplane, N21A, sustained substantial damage during landing at the… ## Other investigations on N21A (1) 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 MIA08LA048](https://openairdocs.org/ntsb/MIA08LA048), Jan 29, 2008: Grumman G-21A (N21A), Marathon, FL, substantial damage. Probable cause: The pilot’s failure to maintain control of the airplane during a water landing. ## Docket (1 files) The files NTSB released with the investigation on April 8, 2003, on NTSB's docket system: https://data.ntsb.gov/Docket?ProjectID=54972. 798 KB in all. - Pilot/Operator Aircraft Accident Report, NTSB Form 6120.1 (item 1, .PDF, 798 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40447049&FileExtension=.PDF&FileName=Pilot%2FOperator%20Aircraft%20Accident%20Report,%20NTSB%20Form%206120.1-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.