# NTSB GAA17CA440: Mitchell Derryle V Rans S 7 Courier, N6333Y, Cordova, AK, July 23, 2017 - Type: NTSB accident investigation - Classification: Accident · No injuries · Data collection · Final report - Date: July 23, 2017, 04:50 local (12:50 UTC) - Place: Cordova, AK - Coordinates: 60.538055, -145.660278 (estimated) - Nearby events: https://openairdocs.org/map.md?lat=60.5381&lon=-145.6603&mi=10 - Phase of flight: [Takeoff](https://openairdocs.org/ntsb-phases/300) (OpenAirDocs' grouping) - Defining event: [Takeoff: Loss of lift](https://openairdocs.org/ntsb-events/500) - Highest injury: No injuries - Injuries: 1 uninjured - Status: Completed, report October 24, 2018 - Report: Approved by Office Director - NTSB office: General Aviation Accidents - Parties: FAA - NTSB case key (mKey): 95669 - NTSB case page: https://web.ntsb.gov/investigations/?ntsbnumber=GAA17CA440 - NTSB report (PDF, downloads): https://data.ntsb.gov/carol-repgen/api/Aviation/ReportMain/GenerateNewestReport/95669/pdf - NTSB docket: https://data.ntsb.gov/Docket?ProjectID=95669 - Page: https://openairdocs.org/ntsb/GAA17CA440 ## Probable cause The pilot’s improper decision to take off from a lake in gusting wind conditions, which resulted in a loss of airplane control. ## Findings NTSB's coded findings; those marked are part of the probable cause. - [Wind: downdraft](https://openairdocs.org/ntsb-findings/03034035): Environmental issues › Conditions/weather/phenomena · Effect on operation (probable cause); cases with it: [Mitchell Derryle V RANS S-7 COURIER, 1 case](https://openairdocs.org/ntsb-findings/03034035/cases.md?model=05606EC), [All aircraft, 178 cases](https://openairdocs.org/ntsb-findings/03034035/cases.md) - [Use of equip/info: aircraft control](https://openairdocs.org/ntsb-findings/02063040): Personnel issues › Task performance · Pilot (probable cause); cases with it: [Mitchell Derryle V RANS S-7 COURIER, 1 case](https://openairdocs.org/ntsb-findings/02063040/cases.md?model=05606EC), [All aircraft, 9,295 cases](https://openairdocs.org/ntsb-findings/02063040/cases.md) - [Performance/control parameters](https://openairdocs.org/ntsb-findings/01062000): Aircraft › Aircraft oper/perf/capability · Not attained/maintained (probable cause); cases with it: [Mitchell Derryle V RANS S-7 COURIER, 1 case](https://openairdocs.org/ntsb-findings/01062000/cases.md?model=05606EC), [All aircraft, 1,269 cases](https://openairdocs.org/ntsb-findings/01062000/cases.md) - [Info processing/decision: decision making/judgment](https://openairdocs.org/ntsb-findings/02041520): Personnel issues › Action/decision · Pilot (probable cause); cases with it: [Mitchell Derryle V RANS S-7 COURIER, 1 case](https://openairdocs.org/ntsb-findings/02041520/cases.md?model=05606EC), [All aircraft, 3,098 cases](https://openairdocs.org/ntsb-findings/02041520/cases.md) - [Wind: gusts](https://openairdocs.org/ntsb-findings/03034045): Environmental issues › Conditions/weather/phenomena · Effect on operation; cases with it: [Mitchell Derryle V RANS S-7 COURIER, 1 case](https://openairdocs.org/ntsb-findings/03034045/cases.md?model=05606EC), [All aircraft, 1,199 cases](https://openairdocs.org/ntsb-findings/03034045/cases.md) ## Sequence of events The events NTSB coded, in order, by phase of flight. The defining event best describes what happened. - [Takeoff: Other weather encounter](https://openairdocs.org/ntsb-events/400); cases with it: [Mitchell Derryle V RANS S-7 COURIER, 1 case](https://openairdocs.org/ntsb-events/400/sequence.md?model=05606EC), [All aircraft, 1,127 cases](https://openairdocs.org/ntsb-events/400/sequence.md) - [Takeoff: Loss of lift](https://openairdocs.org/ntsb-events/500) (defining event); cases with it: [Mitchell Derryle V RANS S-7 COURIER, 1 case](https://openairdocs.org/ntsb-events/500/sequence.md?model=05606EC), [All aircraft, 252 cases](https://openairdocs.org/ntsb-events/500/sequence.md) - [Takeoff: Loss of control in flight](https://openairdocs.org/ntsb-events/240); cases with it: [Mitchell Derryle V RANS S-7 COURIER, 1 case](https://openairdocs.org/ntsb-events/240/sequence.md?model=05606EC), [All aircraft, 5,002 cases](https://openairdocs.org/ntsb-events/240/sequence.md) - [Takeoff: Attempted remediation/recovery](https://openairdocs.org/ntsb-events/060); cases with it: [Mitchell Derryle V RANS S-7 COURIER, 1 case](https://openairdocs.org/ntsb-events/060/sequence.md?model=05606EC), [All aircraft, 1,422 cases](https://openairdocs.org/ntsb-events/060/sequence.md) - [Takeoff: Collision with terr/obj (non-CFIT) ](https://openairdocs.org/ntsb-events/470); cases with it: [Mitchell Derryle V RANS S-7 COURIER, 1 case](https://openairdocs.org/ntsb-events/470/sequence.md?model=05606EC), [All aircraft, 10,189 cases](https://openairdocs.org/ntsb-events/470/sequence.md) - [Takeoff: Nose over/nose down](https://openairdocs.org/ntsb-events/096); cases with it: [Mitchell Derryle V RANS S-7 COURIER, 1 case](https://openairdocs.org/ntsb-events/096/sequence.md?model=05606EC), [All aircraft, 2,287 cases](https://openairdocs.org/ntsb-events/096/sequence.md) ## Analysis The pilot of the float-equipped airplane reported that, following takeoff from a lake, he turned to left downwind about 750 ft above the water. He added that, once the turn was completed, the airplane encountered a strong downdraft, which "pushed [the] tail of [the airplane] down and away to [the] left," and the airplane began to descend. The pilot corrected with left rudder and was able to "straighten [the airplane] just prior to [the] right float tip contacting water." The airplane impacted the water, nosed over, and sank. The pilot egressed without further incident. The airplane sustained substantial damage to both wings. The pilot reported that there were no preaccident mechanical failures or malfunctions with the airplane that would have precluded normal operation. The pilot reported on the NTSB Form 6120.1 that the wind was from the east/southeast at 15 to 20 knots, gusting to 25 knots. The pilot reported a takeoff to the east. A review of recorded data from an automated weather observation station located about 7 nautical miles east of the accident, about the time of the accident, revealed winds calm; 10 statues miles visibility; few clouds at 600 ft, scattered clouds at 1,200 ft, and an overcast ceiling at 3,200 ft; temperature 54°F; dew point 54°F; and an altimeter setting at 30.19 inches of mercury. The computed density altitude at 750 ft was 322 ft. The Federal Aviation Administration's Airport Facility Directory for an airport 2 nautical miles west of the accident site stated, in part: "strong East winds, rwy subj to strong downdrafts." ## Factual narrative The pilot of the float-equipped airplane reported that, following takeoff from a lake, he turned left downwind about 750 ft. above the water. He added that, once the turn was completed, the airplane encountered a strong downdraft, which "pushed [the] tail of [the airplane] down and away to [the] left" and the airplane began to descend. The pilot corrected with left rudder and was able to "straighten [the airplane] just prior to [the] right float tip contacting water." The airplane impacted the water, nosed over, and sank. The pilot egressed without further incidence. The airplane sustained substantial damage to both wings. The pilot reported that there were no preaccident mechanical failures or malfunctions with the airplane that would have precluded normal operation. The pilot reported on the NTSB Form 6120.1 that the wind was from the east/southeast at 15 to 20 knots, gusting to 25 knots. The pilot reported a takeoff to the east. A review of recorded data from an automated weather observation station located about 7 nautical miles to the east of the accident, about the time of the accident, reported winds calm, 10 statues miles visibility, few clouds at 600 ft, scattered clouds at 1,200 ft, and an overcast ceiling at 3,200 ft, temperature 54°F, dew point 54°F, and an altimeter setting at 30.19" Hg. The computed density altitude at 750 ft. was 322 ft. The Federal Aviation Administration's Airport Facility Directory, for an airport 2 nautical miles west of the accident site, states in part: "strong East winds, rwy subj to strong downdrafts." ## Aircraft - Registration: [N6333Y](https://openairdocs.org/deregistered/N6333Y-2020-01-28), registration cancelled 2020-01-28, S/N 0596188, built 1998 (OpenAirDocs) - Reported make and model: MITCHELL DERRYLE V RANS S 7 COURIER (NO SERIES) - Registry model: [Mitchell Derryle V RANS S-7 COURIER](https://openairdocs.org/model/mitchell-derryle-v-rans-s-7-courier) (registry code 05606EC) (OpenAirDocs) - Registry engine: [Bombardier ROTAX (ALL)](https://openairdocs.org/engine/bombardier-rotax-all) (registry code 09050, reciprocating) (OpenAirDocs) - Category: Airplane, amateur-built - Serial number: 0596188 - Year built: 1998 - Airframe hours: 335.4 - Engines: Rotax 912 UL 105 horsepower reciprocating - Damage: Substantial damage - Flight: Personal, Part 91 - Airworthiness certificate: Special, Experimental (Special) - Last inspection: Annual, April 4, 2017 - Departed: CKU, Cordova, AK - Destination: CKU, Cordova, AK - Airport: CKU, Cordova Muni - Equipment: Handheld GPS ## Flight crew As NTSB recorded them. NTSB leaves out names. - Pilot; age 49; injuries: none; private; airplane ratings: single-engine sea, single-engine land; medical: class 3, with waivers/limitations; last flight review April 11, 2017; seat: front; restraint: 3-point; flight hours: 387 total, 100 in this make and model, 233 as pilot in command, 108 in the last 90 days, 70 in the last 30 days, 7 in the last 24 hours ## Weather - Conditions: Visual (VMC), Dawn - Wind: calm - Visibility: 10 statute miles - Lowest ceiling: 3,200 ft overcast - Temperature: 54 °F, dew point 54 °F - Altimeter: 30.19 inHg - Observed at: PACV, 7 nm away ## 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 20170723012609A](https://openairdocs.org/incident/20170723012609A), Jul 23, 2017: Mitchell Derryle V RANS S-7 COURIER, Cordova, AK, Substantial damage. After takeoff from cdv, eyak lake, at 700' pilot made a left turn. A sudden down draft caused the aircraft sink rate to be too difficult to overcome. Aircraft… ## Docket (3 files) The files NTSB released with the investigation on September 13, 2018, on NTSB's docket system: https://data.ntsb.gov/Docket?ProjectID=95669. 1.5 MB in all. - Pilot/Operator Aircraft Accident Report, NTSB Form 6120.1 (item 1, .PDF, 1.1 MB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40456204&FileExtension=.PDF&FileName=Pilot%2FOperator%20Aircraft%20Accident%20Report,%20NTSB%20Form%206120.1-Master.PDF - FAA Airport Facility Directory (item 2, .PDF, 79 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40466657&FileExtension=.PDF&FileName=FAA%20Airport%20Facility%20Directory-Master.PDF - Accident Photo (item 3, .PDF, 1 photo, 273 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40466658&FileExtension=.PDF&FileName=Accident%20Photo-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.