High Island 571 Platform Airport
Aircraft Accident/Incident Report

Galveston, Texas 77550
Wednesday, June 18, 1986 9:55 CST

NTSB Narrative Summary Released at Completion of Accident

THE PLT RPRTD THAT WHILE APCHG AN OIL DRILLING PLATFORM FOR A LNDG, HE OBSERVED THE MAIN ROTOR BLADES GO OUT OF TRACK ABOUT 8 TO 10 INCHES. HE ALSO RPRTD THE HELICOPTER DEVELOPED A 1:1 VERTICAL VIBRATION. DRG THE LNDG, THE HELICOPTER ENTERED INTO GROUND RESONANCE & THE PLT IMMEDIATELY SHUT DOWN BOTH ENGINES. AN EXAM OF THE HELICOPTER REVEALED THE LEFT FORWARD TRANSMISSION SUPPORT BAR (TSB) WAS BUCKLED & CRACKED AT MIDSPAN. A METALLURGICAL EXAM OF THE FRACTURE AREA ON THE TSB REVEALED EXTENSIVE, LOW CYCLE, HIGH AMPLITUDE, FATIGUE CRACKING. THERE WAS EVIDENCE THAT THE PROPAGATION TIME OFTHE FATIGUE OCCURRED OVR ABOUT 5 HRS OF OPN. THE INV DID NOT REVEAL WHEN THE ORIGINAL BUCKLING OF THE TSB OCCURRED. NO HISTORY OF A PREV HARD LNDG OR GND REASONANCE WAS FND. ALSO, THE RED ARM OF THE STARFLEX HAD FAILED; AN EXAM INDCD IT HAD RUPTURED EITHER UNDER STATIC LOADS, OR VERY RAPIDLY UNDER HI DYNAMIC LOADS. WHEN TESTED, EXTN & RETRACTION TIMES OF LNDG GEAR DAMPERS WERE 8.34 TO 10.38 SEC; AFTER ACDNT, TIME LMTS ESTABLISHED AT 6 TO 13 SEC, PREVIOUSLY 11.1 TO 13.1 SEC

NTSB Probable Cause Narrative

Not Yet Reported

Event Information

Type of Event Accident
Event Date 6/18/1986
Event Day of the Week Wednesday
Time of Event 955
Event Time Zone Central Standard Time
Event City GALVESTON
Event State TEXAS
Event Country --
Zipcode of the event site 77550
Event Date Year 1986
Event Date Month 6
MidAir Collision Indicator No
On Ground Collision occurred ? No
Event Location Latitude
Event Location Longitude
Event Location Airport HIGH ISLAND 571 PLATFORM
Event Location Nearest Airport ID
Indicates whether the acc/inc occurred off or on an airport On Airport
Distance from airport in statute miles 0
Degrees magnetic from airport 0
Airport Elevation 25
Weather Briefing Completeness Not pertinent
Investigator's weather source Weather Observation Facility
Time of the weather observation 955
Direction of event from weather observation facility (degrees) 0
Weather Observation Facility ID
Elevation of weather observation facility 25
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 8000
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) 15
Air Temperature at event time (in degrees celsius) 28
Dew Point at event time (in degress fahrenheit) 21
Wind Direction (degrees magnetic) 300
Variable Wind Indicator Unknown
Wind Speed (knots) 3
Wind Velocity Indicator Unknown
Wind Gust Indicator Not Gusting
Wind Gust (knots) 0
Altimeter Setting at event time (in. Hg) 30
Density Altitude (feet) --
Intensity of Precipitation Unknown
METAR weather report --
Event Highest Injury None
On Ground, Fatal Injuries 0
On Ground, Minor Injuries 0
On Ground, Serious Injuries 0
Injury Total Fatal --
Injury Total Minor --
Injury Total None 1
Injury Total Serious --
Injury Total All --
Investigating Agency NTSB
NTSB Docket Number (internal use) 2638
NTSB Notification Source --
NTSB Notification Date Jun 19 1986 12:00AM
NTSB Notification Time 1600
Fiche Number and/or location -used to find docket information 33874
Date of most recent change to record Dec 13 2000 4:07PM
User who most recently changed record dbo
Basic weather conditions Visual Meteorological Cond
FAA District Office --

Aircraft Involved

Aircraft #1

Aircraft Registration Number N5796T
NTSB Number LAX86MA268
Missing Aircraft Indicator N
Federal Aviation Reg. Part Part 91: General Aviation
Type of Flight Plan filed None
Flight plan Was Activated? --
Damage Substantial
Aircraft Fire None
Aircraft Explosion None
Aircraft Manufacturer's Full Name AEROSPATIALE
Aircraft Model AS-355F-1
Aircraft Series Identifier AS-355F-1
Aircraft Serial Number 5166
Certified Max Gross Weight 4600
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 Continuous Airworthiness
Date of Last Inspection Jun 5 1986 12:00AM
Airframe hours since last inspection 20
Airframe Hours 3500
ELT Installed No
ELT Activated No
ELT Aided Location of Event Site No
ELT Type --
Aircraft Owner Name PETROLEUM HELICOPTERS, INC.
Aircraft Owner Street Address P.O. BOX 90808
Aircraft Owner City LAYFAYETTE
Aircraft Owner State LA
Aircraft Owner Country
Aircraft Owner Zipcode 70509
Operator is an individual? --
Operator Name
Operator Same as Owner? Yes
Operator Is Doing Business As --
Operator Address Same as Owner? Yes
Operator Street Address
Operator City
Operator State
Operator Country
Operator Zip code
Operator Code PHI
Owner has at least one certificate Yes - certificate holder
Other Operator of large aircraft? No
Certified for Part 133 or 137 Operation External Load
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) Positioning
Second Pilot on Board No
Departure Point Same as Event No
Departure Airport Code
Departure City HIGH ISLAND 571
Departure State TX
Departure Country
Departure Time 950
Departure Time Zone CDT
Destination Same as Local Flt crash at destination city
Destination Airport Code
Destination City
Destination State
Destination Country
Specific Phase of Flight Landing
Report sent to ICAO? --
Evacuation occurred --
Date of most recent change to record Jan 2 2001 10:36AM
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 No
Air Medical Flight No
Medical Flight --