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ASN Wikibase Occurrence # 39415
Last updated: 13 October 2019
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Date:25-DEC-1984
Time:16:05
Type:Silhouette image of generic R22 model; specific model in this crash may look slightly different
Robinson R22 Alpha
Owner/operator:Executive Air Inc
Registration: N8475K
C/n / msn: 391
Fatalities:Fatalities: 2 / Occupants: 2
Other fatalities:0
Aircraft damage: Written off (damaged beyond repair)
Category:Accident
Location:near Huntsville, Alabama -   United States of America
Phase: En route
Nature:Private
Departure airport:Decatur, Alabama (DCU/KDCU)
Destination airport:
Investigating agency: NTSB
Narrative:
On December 25, 1984, approximately 16:15 CST (Central Standard Time), N8475K, a Robinson R22 Alpha, operated by Executive Air, Inc., broke up in flight near Huntsville, Alabama, during a personal flight. The flight had originated at Decatur, Alabama, at 13:30 CST. Before the accident, the helicopter was seen in cruise, at 400 to 600 feet elevation, heading west. One witness reportedly heard a loud noise and observed the helicopter falling vertically. Another witness stated he observed a puff of black smoke and saw parts separating from the helicopter. Both the pilot and passenger were killed.

The weather at the time of the accident was reportedly clear with 15 miles visibility, winds from 010 degrees at 8 knots, and no reported gusts. The pilot held an airline transport pilot certificate with commercial pilot privileges in
rotorcraft. The pilot also held airman ratings for airplane multi-engine land, sea, and glider, and he held an airframe and powerplant mechanic certificate. The pilot's flight logs and reported flight experience was so inconsistently reported that the Safety Board was unable to determine his total flight experience or his relevant experience in helicopters.

The Safety Board's examination of the wreckage found parts of the helicopter scattered over an area 400 by 700 feet. The pilot's body was found 141 feet from the fuselage. The pilot's seat cushion and windscreen centerpost (with the compass attached) were also located 365 feet and 85 feet east of the main wreckage, respectively. There was evidence that one main rotor blade had struck the windscreen about 2 feet left of the centerpost and traveled aft to the rear of the left passenger's seat. One of the main rotor blades exhibited downward bending and evidence that the blade had contacted the fuselage.

The main rotor mast separated at the top of the transmission in an overload fracture, resembling the fracture of the transmission upper cap. The upper main rotor mast was bent above the swashplate, where the main rotor hub contacts the shaft. One of the droop stops was fractured and the other droop stop was deformed. The main rotor shaft and droop stop damage was consistent with the rotor blades traveling beyond their design limits in the up and down direction (flapping). Both pitch change links were fractured at the top of the jam nut and upper adjustment threads and exhibited overload fractures.

Sources:

1. NTSB Identification: ATL85FA067: https://www.ntsb.gov/ntsb/brief.asp?ev_id=20001214X41702
2. FAA: http://registry.faa.gov/aircraftinquiry/NNum_Results.aspx?omni=Home-N-Number&nNumberTxt=8475K
3. http://www.griffin-helicopters.co.uk/accidentdetails.aspx?accidentkey=35152


Revision history:

Date/timeContributorUpdates
24-Oct-2008 10:30 ASN archive Added
07-Feb-2016 21:41 Dr.John Smith Updated [Time, Operator, Location, Departure airport, Source, Narrative]
07-Feb-2016 21:52 Dr.John Smith Updated [Narrative]
17-Sep-2016 22:56 Dr.John Smith Updated [Location, Departure airport, Source, Narrative]
21-Dec-2016 19:23 ASN Update Bot Updated [Time, Damage, Category, Investigating agency]

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