# NTSB ANC93LA075: Cessna 185F, N185TD, Gustavus, AK, May 31, 1993 - Type: NTSB accident investigation - Classification: Accident · No injuries · Limited investigation · Final report - Date: May 31, 1993, 11:30 local (19:30 UTC) - Place: Gustavus, AK - Coordinates: 58.420082, -135.780517 (estimated) - Nearby events: https://openairdocs.org/map.md?lat=58.4201&lon=-135.7805&mi=10 - Phase of flight: [Landing](https://openairdocs.org/ntsb-phases/550) (OpenAirDocs' grouping) - Highest injury: No injuries - Injuries: 2 uninjured - Status: Completed, report September 15, 1994 - Report: Approved by Office Director - NTSB office: Alaska Regional Office - NTSB case key (mKey): 2348 - NTSB case page: https://web.ntsb.gov/investigations/?ntsbnumber=ANC93LA075 - NTSB report (PDF, downloads): https://data.ntsb.gov/carol-repgen/api/Aviation/ReportMain/GenerateNewestReport/2348/pdf - Page: https://openairdocs.org/ntsb/ANC93LA075 ## Probable cause THE PILOT MISJUDGING HIS SPEED WHILE LANDING ON A WET GRASS STRIP. ## Sequence of events In NTSB's coding before 2008 (https://www.ntsb.gov/GILS/Documents/codman.pdf). - Overrun, landing - roll - airspeed - misjudged, pilot in command (cause) - airport facilities,runway/landing area condition - grass (contributing factor) - airport facilities,runway/landing area condition - wet (contributing factor) - Main gear collapsed, landing - roll - landing gear,main gear - overload ## Analysis THE PILOT STATED HE WAS USING FULL FLAPS AND AN APPROACH SPEED OF 65 KTS. HE TOUCHED DOWN 400 FT BEYOND THE THRESHOLD OF THE 1200-FT STRIP. HE REPORTED THE BRAKING ACTION AS 'NIL' ON THE WET GRASS. THE AIRPLANE OVERRAN THE END OF THE AIRSTRIP AND STRUCK A DITCH, COLLAPSING THE MAIN LANDING GEAR. THE PILOT OPERATOR'S HANDBOOK SUPPLEMENT FOR THE ROBERTSON STOL CONVERSION STATES THAT THE NORMAL GROUND ROLL IS 310 FT WITH FULL FLAPS, 58 KTS INDICATED AT 50 FT, AND HEAVY BRAKING ON HARD SURFACED RUNWAYS, AND THAT THIS DISTANCE SHOULD BE INCREASE BY 20% FOR DRY GRASS RUNWAYS. ## Factual narrative On May 31, 1993, at 1130 Alaska daylight time, a wheel equipped Cessna 185 airplane, N185TD, registered to and operated by the Pilot in Command, over ran the runway at the Glacier Bay Country Inn Airstrip located near Gustavus, Alaska. The personal flight, operating under 14 CFR Part 91, last departed the Glacier Bay Country Inn Airstrip for a local flight. No flight plan was filed and visual meteorological conditions prevailed. The Private Certificated Pilot in Command and the passenger were not injured and the airplane received substantial damage. According to the Pilot in Command, the grass strip was wet and he landed approximately 400 feet beyond the threshold of the 1200 foot long airstrip. The airplane was STOL equipped. He stated that there was no braking effect on the wet grass and the airplane slid off the end of the airstrip, struck a ditch and collapsed the gear and damaged the wing. According to the Pilot Operating Handbook Supplement (POHS 10-6), furnished by Robertson when an airplane is modified with a Robertson STOL kit under Supplemental Type Certificate SA1441WE, the Robertson NORMAL landing data at a gross weight of 3350 pounds, 40 degree (full) flaps, 58 knots at 50 feet above the ground at sea level pressure and 59 degrees Fahrenheit temperature, the ground roll should be 310 feet and 890 feet to clear a 50 foot obstacle. The note section states that the distances are based on zero wind, power off, and heavy braking. It also states that for operation on "dry, grass" runways, to increase the distances for both the ground roll and total to clear 50 foot obstacle by 20% of the "total to clear 50 foot." According to the Pilot in Command, he was using full flaps, and an approach speed of 65 knots indicated. He touched down 400 feet beyond the threshold of a 1200 foot airstrip which left 800 feet remaining. The grass was wet and he stated the braking action was "nil." By applying the POHS information, the airplane should have had a ground roll of 362 feet. However, the POHS does not show what increase in ground roll should be applied when the grass is wet or when a higher approach speed is used. ## Aircraft - Registration: [N185TD](https://openairdocs.org/aircraft/N185TD), registered now, S/N 18504136, built 1980 (OpenAirDocs) - Reported make and model: CESSNA 185F - Registry model: [Cessna A185F](https://openairdocs.org/model/cessna-a185f) (registry code 2072821) (OpenAirDocs) - Registry engine: [Continental IO-520 series](https://openairdocs.org/engine/continental-io-520-series) (registry code 17032, reciprocating) (OpenAirDocs) - Category: Airplane - Serial number: 18504136 - Airframe hours: 525 - Engines: CONTINENTAL IO-520-D 300 horsepower reciprocating - Damage: Substantial damage - Flight: Personal, Part 91 - Operator: Carpenter, Peter F. - Registered owner: Carpenter, Peter F. - Airworthiness certificate: Standard, Normal - Last inspection: Annual, May 10, 1993, 15 hours before - Airport: Glacier Bay Country Inn, runway 36, 1,222 × 100 ft, grass/turf ## Flight crew As NTSB recorded them. NTSB leaves out names. - Pilot; age 53; private; airplane ratings: single-engine land; medical: class 2, valid medical--w/ waivers/lim; seat: left; flight hours: 360 total, 160 in this make and model, 186 as pilot in command, 38 in the last 90 days, 7 in the last 30 days, 3 in the last 24 hours ## Weather - Conditions: Visual (VMC), Day - Wind: calm - Visibility: 30 statute miles - Lowest ceiling: 4,000 ft broken - Temperature: 61 °F ## 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 19930531015589A](https://openairdocs.org/incident/19930531015589A), May 31, 1993: Cessna STC185, Gustavus, AK, Substantial damage. Unable to stop stol equipped aircraft on short wet grass strip. Slid off end runway into ditch. 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.