Aircraft Accident/Incident History

Date: 09 Nov 1968
Description:
Total flight hours at this point: 584
Accident case number: 681109091 Total loss or fatality Accident
Unit: 71 AHC
The station for this helicopter was Chu Lai in
Number killed in accident = 0 . . Injured = 0 . . Passengers = 0
costing 228554
Source(s) from which the incident was created or updated: Army Aviation Safety Center database.

Crew Members:
AC W1 HOLLY RF
P W1 POWELL WA

Accident Summary:

Aircraft UH-1, 67-17418 and crew were assigned a mission to make a VIP passenger pickup at Da Nang main airfield and return to Marble Mountain airfield. At approximately 0915 hours, the aircraft took off with six passengers aboard and 600 pounds of fuel. The available fuel was more than enough for the anticipated 20 minutes flying time required for this mission. As there were several rain showers in the area and a low ceiling, the aircraft commander requested and received a special VFR clearance from Marble Mountain to Da Nang main airfield. At some time almost immediately after takeoff, the “T” head bolt on the clamp assembly failed allowing the clasp assembly to vibrate loose and the main fuel filter bowl to separate from the filter seat. System fuel pressure forced fuel out of this separation. Entering the traffic pattern at Da Nang main, the aircraft commander noted 400 pounds of fuel remaining prior to the “20 minute fuel” warning light coming on and decided to return to Marble Mountain. Maintenance facilities are available at Marble Mountain and duration of flight to return was approximately 5 minutes. The heavy smell of fuel fumes confirmed the aircraft commanders conclusion that there was a fuel leak even though there was no discernable exterior fuel leakage. After setting down at Marble Mountain airfield, the density of the fumes apparently was touched off by contact with the engine exhaust. JP-4 fuel fumes have a low flash point. The extent of fire damage to the tail boom indicates that the fuel was carried back into the tail boom while the aircraft was in flight. Immediate shutdown of the helicopter cut off the fuel system pressure, however approximately 150 to 175 pounds of fuel apparently was trapped in the inner compartments and the tail boom when the fumes flashed into fire. The rapid reaction time of the fire fighters precluded further damage to the airframe.

Aircraft Assignment History