Aircraft Accident/Incident Report

Saipan India
Saturday, December 6, 1997 16:49

NTSB Narrative Summary Released at Completion of Accident

The pilot reported that he was making a standard approach to the helicopter pad which was located on a bluff overlooking a golf course. About 100 yards from the pad and 150 feet agl, he noticed a twitch in the nose of the aircraft and heard the rpm decreasing and the engine spooling down. He entered an autorotation and turned the helicopter to the right to avoid upsloping terrain. The aircraft touched down hard and the landing gear collapsed and the tail rotor struck the ground. The pilot stated that after coming to a stop, the engine was still idling so he closed the fuel shutoff valve and throttle and turned off all electrical power. The engine took about 20 to 30 seconds to spool down. The fuel control components were then tested at the Allied Signal Materials Technology Center in South Bend, Indiana, under the auspices of the FAA. Operational bench tests performed on the fuel control and governor indicated that the fuel control would meter minimum fuel flow throughout the various test points and that the acceleration bellows assembly was the probable source for the uncommanded minimum fuel flow condition. A leak was found in the bellows which stemmed from a corrosion pit that penetrated through the outer ply of a convolution tube at the edge of a braze fillet. The pit caused evacuation and malfunction of the bellows. Allied Signal and Allison Engines issued service bulletins on November 18, 1993, regarding the replacement of the fuel control bellows. The Allison Commercial Engine Bulletin CEB-A-282 directed that the beryllium copper bellows be replaced by a stainless steel welded Pc Inconel Bellows the next time the affected fuel control was at a repair/overhaul facility and the bellows area was disassembled for any reason, but in no case later than the next fuel control unit overhaul. The aircraft maintenance records revealed that on April 22, 1997, an overhaul of the fuel control assembly was performed. On a form indicating compliance with applicable service bulletins and directives, 'NA' was written by the maintenance facility in the space next to the listing for the Allison CEB-282. The records revealed that the fuel control with the beryllium copper Pc bellows was reinstalled in the helicopter on October 1, 1997, at engine time 2,247.1 hours, 39 hours prior to the accident.

NTSB Probable Cause Narrative

The failure of the maintenance facility to comply with the service bulletins, which resulted in the development of a corrosion pit, subsequent leakage and failure of the acceleration bellows of the fuel control.

Event Information

Type of Event Accident
Event Date 12/6/1997
Event Day of the Week Saturday
Time of Event 1649
Event Time Zone --
Event City SAIPAN
Event State --
Event Country INDIA
Zipcode of the event site 96950
Event Date Year 1997
Event Date Month 12
MidAir Collision Indicator No
On Ground Collision occurred ? No
Event Location Latitude
Event Location Longitude
Event Location Airport
Event Location Nearest Airport ID
Indicates whether the acc/inc occurred off or on an airport Off Airport/Airstrip
Distance from airport in statute miles --
Degrees magnetic from airport --
Airport Elevation --
Weather Briefing Completeness Not pertinent
Investigator's weather source Weather Observation Facility
Time of the weather observation 1700
Direction of event from weather observation facility (degrees) 0
Weather Observation Facility ID PGS
Elevation of weather observation facility 215
Distance of event from weather observation facility (units?) 0
Time Zone of the weather observation
Lighting Conditions Day
Lowest Ceiling Height 0
Lowest Non-Ceiling Height 1500
Sky/Lowest/Cloud Conditions Scattered
Sky Condition for Lowest Ceiling None
Visibility Runway Visual Range (Feet) 0
Visibility Runway Visual Value (Statute Miles) 0
Visibility (Statute Miles) 7
Air Temperature at event time (in degrees celsius) 28
Dew Point at event time (in degress fahrenheit) 23
Wind Direction (degrees magnetic) 70
Variable Wind Indicator Unknown
Wind Speed (knots) 13
Wind Velocity Indicator Unknown
Wind Gust Indicator Not Gusting
Wind Gust (knots) 0
Altimeter Setting at event time (in. Hg) 29
Density Altitude (feet) --
Intensity of Precipitation Unknown
METAR weather report --
Event Highest Injury Minor
On Ground, Fatal Injuries 0
On Ground, Minor Injuries 0
On Ground, Serious Injuries 0
Injury Total Fatal --
Injury Total Minor 5
Injury Total None --
Injury Total Serious --
Injury Total All 5
Investigating Agency NTSB
NTSB Docket Number (internal use) 1880
NTSB Notification Source --
NTSB Notification Date Dec 6 1997 12:00AM
NTSB Notification Time 100
Fiche Number and/or location -used to find docket information IMAGE
Date of most recent change to record Dec 8 2000 12:43PM
User who most recently changed record dbo
Basic weather conditions Visual Meteorological Cond
FAA District Office --

Aircraft Involved

Aircraft #1

Aircraft Registration Number N9068F
NTSB Number LAX98LA053
Missing Aircraft Indicator N
Federal Aviation Reg. Part Part 91: General Aviation
Type of Flight Plan filed Company VFR
Flight plan Was Activated? --
Damage Destroyed
Aircraft Fire None
Aircraft Explosion None
Aircraft Manufacturer's Full Name McDonnell Douglas
Aircraft Model 369HS
Aircraft Series Identifier 369HS
Aircraft Serial Number 210293S
Certified Max Gross Weight 2550
Aircraft Category Helicopter
Aircraft Registration Class U.S. Registered/U.S. Soil
Aircraft is a homebuilt? No
Flight Crew Seats --
Cabin Crew Seats --
Passenger Seats --
Total number of seats on the aircraft 5
Number of Engines 1
Fixed gear or retractable gear Fixed
Aircraft, Type of Last Inspection Annual
Date of Last Inspection Aug 27 1997 12:00AM
Airframe hours since last inspection 41
Airframe Hours 1806
ELT Installed Unknown
ELT Activated Unknown
ELT Aided Location of Event Site Unknown
ELT Type --
Aircraft Owner Name UREN CONSTRUCTION COMPANY
Aircraft Owner Street Address P.O. BOX 38
Aircraft Owner City WOODINVILLE
Aircraft Owner State WA
Aircraft Owner Country
Aircraft Owner Zipcode 98072
Operator is an individual? --
Operator Name MICRONESIAN AVIATION CORP
Operator Same as Owner? No
Operator Is Doing Business As --
Operator Address Same as Owner? No
Operator Street Address P.O. BOX 1160
Operator City SAIPAN
Operator State MP
Operator Country
Operator Zip code 96950
Operator Code FCYA
Owner has at least one certificate Yes - certificate holder
Other Operator of large aircraft? No
Certified for Part 133 or 137 Operation Unknown
Operator Certificate Number --
Indicates whether an air carrier operation was scheduled or not --
Indicates Domestic or International Flight --
Operator carrying Pax/Cargo/Mail --
Type of Flying (Per_Bus / Primary) Unknown
Second Pilot on Board No
Departure Point Same as Event Yes
Departure Airport Code
Departure City
Departure State MP
Departure Country
Departure Time 0
Departure Time Zone
Destination Same as Local Flt dest & departure same, accident can occur anywhere
Destination Airport Code
Destination City
Destination State
Destination Country
Specific Phase of Flight Approach
Report sent to ICAO? --
Evacuation occurred --
Date of most recent change to record Jan 2 2001 10:34AM
User who most recently changed record dbo
Since inspection or accident --
Event Location Runway Number and Location 0
Runway Length --
Runway Width --
Sight Seeing flight Yes
Air Medical Flight No
Medical Flight --