# NTSB MIA96LA137: Cessna U206G, N9702Z, Gulf Of Mexico, May 5, 1996 - Type: NTSB accident investigation - Classification: Accident · No injuries · Limited investigation · Final report - Date: May 5, 1996, 14:45 local (18:45 UTC) - Place: Gulf Of Mexico - Phase of flight: [Enroute](https://openairdocs.org/ntsb-phases/400) (OpenAirDocs' grouping) - Highest injury: No injuries - Injuries: 6 uninjured - Status: Completed, report December 16, 1996 - Report: Approved by Office Director - NTSB case key (mKey): 38017 - NTSB case page: https://web.ntsb.gov/investigations/?ntsbnumber=MIA96LA137 - NTSB report (PDF, downloads): https://data.ntsb.gov/carol-repgen/api/Aviation/ReportMain/GenerateNewestReport/38017/pdf - Page: https://openairdocs.org/ntsb/MIA96LA137 ## Probable cause Loss of engine power for undetermined reasons. Contributing to the accident was the unsuitable terrain encountered during the forced landing. ## Sequence of events In NTSB's coding before 2008 (https://www.ntsb.gov/GILS/Documents/codman.pdf). - Loss of engine power, cruise - reason for occurrence undetermined (cause) - Hard landing, emergency descent/landing - unsuitable terrain or takeoff/landing/taxi area - encountered, pilot in command (contributing factor) ## Analysis The pilot stated that during cruise flight after takeoff while flying at 500 feet above the water, he first noted that the oil temperature was near the 'high' end and he verified that the cowl flaps were open. The flight continued and the engine then ran rough momentarily then quit. The pilot landed the airplane in a heavy sea state that damaged one of the floats resulting in that float filling with water. All occupants donned personal flotation devices, exited the airplane, and were rescued 3 hours 20 minutes after the forced landing following a search by the Coast Guard, Navy, and civilian airplanes. The pilot further stated that there was no oil on the windscreen following the engine failure. The airplane was not recovered. The engine was rebuilt by the engine manufacturer on June 14, 1994, and had accumulated about 1,033 hours at the time of the failure. ## Factual narrative On May 5, 1996, about 1445 eastern daylight time, a Cessna U206G floatplane, N9702Z, registered to Key West Seaplane Service, Inc., was substantially damaged during a forced landing in the Gulf of Mexico shortly after takeoff from Fort Jefferson, Dry Tortugas Island, Florida. Visual meteorological conditions prevailed at the time and a DVFR flight plan was filed for the 14 CFR Part 135 nonscheduled, domestic, passenger flight. The commercial-rated pilot and five passengers were not injured. The flight originated about 10 minutes earlier from a seaplane base located at the fort. The pilot stated that during cruise flight at 24 inches manifold pressure and 2,450 rpm, about 500 feet above the water, he observed that the oil temperature was near the "high" side. He verified that the cowl flaps were open and the engine momentarily ran rough then quit and the propeller stopped. He landed the airplane on top of a swell in heavy seas and the airplane then bounced, touched down, and remained upright for about 10-15 minutes. The right float which was damaged began filling with water and the airplane began to list. All passengers donned personal flotation devices, exited the airplane which later rolled inverted and sank. The airplane was not recovered. The pilot and several of the passengers reported that there was no oil on the windscreen following the engine malfunction. The pilot further stated that after the engine malfunction, he was unable to contact the pilot of another airplane that was scheduled to depart the fort shortly after his flight departed. According to company personnel, the planned flight was calculated to be 45 minutes. At 1625, the Miami Automated Flight Service Station contacted the Key West Coast Guard Station to advise that the flight was overdue. The Coast Guard, Navy, and civilian airplanes dispatched by the operator launched a search. The pilot of a civilian airplane first spotted the airplane and occupants and dropped a raft. The occupants were rescued by the Coast Guard 3 hours 20 minutes after the forced landing. Review of the engine maintenance records revealed that the engine was rebuilt/zero timed on June 14, 1994, by the engine manufacturer, and it was installed in the accident airplane on January 15, 1995. The engine was operated for 6.9 hours on mineral oil then the remainder of the time using 15W50 oil. Oil samples were recorded as being taken every oil change and the results of the last six are an attachment to this report. The engine logbook also indicates that on April 4, 1996, the No. 1 cylinder was replaced. The engine had accumulated 1,032.9 hours since rebuild. ## Aircraft - Registration: [N9702Z](https://openairdocs.org/deregistered/N9702Z-2013-06-05), registration cancelled 2013-06-05, S/N U20606615, built 1982 (OpenAirDocs) - Reported make and model: Cessna U206G - Registry model: [Cessna U206G](https://openairdocs.org/model/cessna-u206g) (registry code 2073356) (OpenAirDocs) - Registry engine: [Continental IO-520 series](https://openairdocs.org/engine/continental-io-520-series) (registry code 17032, reciprocating) (OpenAirDocs) - Category: Airplane - Serial number: U20606615 - Airframe hours: 6206 - Engines: Continental IO-520F17B 300 horsepower reciprocating - Damage: Substantial damage - Flight: Part 135 - Registered owner: Key West Seaplane Service, Inc - Airworthiness certificate: Standard, Normal - Last inspection: 100 hour, April 28, 1996, 22 hours before - Departed: DTF, DRY TORTUGAS IS, FL - Destination: 6FL5, KEY WEST, FL - Flight plan: VFR ## Flight crew As NTSB recorded them. NTSB leaves out names. - Pilot; age 63; flight instructor, commercial, airline transport; airplane ratings: single-engine sea, multi-engine land, single-engine land; instrument ratings: airplane; medical: class 2, valid medical--w/ waivers/lim; seat: left; flight hours: 10,000 total, 1,000 in this make and model, 10,000 as pilot in command, 70 in the last 90 days, 25 in the last 30 days, 2 in the last 24 hours ## Weather - Conditions: Visual (VMC), Day - Wind: 100° at 9 knots, gusting 14 - Visibility: 10 statute miles - Lowest ceiling: none - Temperature: 82 °F, dew point 72 °F - Altimeter: 30.00 inHg - Observed at: EYW, 45 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 19960505009239A](https://openairdocs.org/incident/19960505009239A), May 5, 1996: Cessna U206G, Key West, FL, Substantial damage. On sightseeing expedition, engine stalled, pilot attempted to land in ocean, rolled over in heavy swells and sunk. 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.