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ASN Wikibase Occurrence # 37585
Last updated: 17 November 2020
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Date:17-MAR-1996
Time:12:37
Type:Silhouette image of generic C206 model; specific model in this crash may look slightly different
Cessna U206G Stationair 6
Owner/operator:Key West Seaplane Service
Registration: N9983Z
C/n / msn: U206-06794
Fatalities:Fatalities: 5 / Occupants: 6
Other fatalities:0
Aircraft damage: Written off (damaged beyond repair)
Location:Stock Island Sea Plane Base, Key West, FL -   United States of America
Phase: Take off
Nature:Passenger - Non-Scheduled/charter/Air Taxi
Departure airport:Stock Island Sea Plane Base, Key West, Florida
Destination airport:Dry Tortugas, FL (DTF)
Narrative:
After takeoff, according to radar data, the airplane climbed to 200 feet, then descended to 100 feet. The pilot was advised to turn right to pass behind the approach corridor for a departing airplane. Witnesses observed the airplane flying towards buildings, and stated that the airplane, which was about 50-100 feet above the water, started banking to the right which increased to near a 90-degree angle of bank. The airplane then pitched nose down and impacted the water nose and right wing low, rolled inverted and sank in about 6 feet of water about 20 yards from a seawall.

Examination and testing of the right magneto revealed that the point gap was 0.018 inch, which is greater than specified by the manufacturer, and the magneto fired intermittently throughout the entire rpm range. After adjusting the point gap to within limits, the right magneto operated normally. The engine was then run with replacement magnetos installed with their point gaps set as found on the accident magnetos. During the right magneto check, the rpm drop was 156 rpm greater than the left magneto check. Damage was also noted to the #1 cylinder top ignition lead. Examination of the aft bottom section of the right float revealed numerous damaged rivets which join the keel to the bottom skin panel near the aft bulkhead.

CAUSE: The pilot's improper decision to continue the flight rather than making an immediate water landing due to the low altitude of the airplane and obstructions ahead, which led to his intentional maneuver to avoid the obstructions and subsequent inadvertent stall and loss of control. Contributing to the accident were: an inadequate 100-hour inspection of the airplane by company maintenance personnel for failure to fix a damaged ignition lead and a partially separated keel on one of the floats, the pilot's inadequate preflight of the airplane for his failure to pump a float to remove water, and the pilot's intentional operation of the airplane with an excessive magneto drop.

Sources:

1. NTSB Identification MIA96FA100 at https://www.ntsb.gov/_layouts/ntsb.aviation/brief2.aspx?_ ev_id=20001208X05447&ntsbno=MIA96FA100&akey=1
2. FAA: http://registry.faa.gov/aircraftinquiry/NNum_Results.aspx?omni=Home-N-Number&nNumberTxt=9983Z


Revision history:

Date/timeContributorUpdates
24-Oct-2008 10:30 ASN archive Added
13-Jul-2016 16:40 Dr.John Smith Updated [Location, Nature, Departure airport, Source, Narrative]
05-Nov-2016 21:34 Dr.John Smith Updated [Time, Cn, Source]
21-Dec-2016 19:23 ASN Update Bot Updated [Time, Damage, Category, Investigating agency]
11-Oct-2017 16:07 TB Updated [Aircraft type, Location]

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