N81671 – Bell Textron 206L-3 – 2003-10-10 NTSB Accident Report

HISTORY OF FLIGHT

On October 10, 2003, approximately 1049 central daylight time, a Bell 206L-3 single-engine helicopter, N81671, call sign Sierra 61, registered to and operated by Petroleum Helicopters, Inc. (PHI), of Lafayette, Louisiana, was destroyed when it impacted water following a loss of control while maneuvering near offshore platform West Cameron (WC) 509, located in the Gulf of Mexico. The commercial pilot and two passengers were fatally injured. Instrument metrological conditions (IMC) prevailed, and a company visual flight rules (VFR) flight plan was filed for the 14 Code of Federal Regulations (CFR) Part 135 on-demand air taxi flight. The local flight departed platform High Island (HI) 330 at 1006, and was destined for West Cameron 509, with an estimated time of arrival of 1030.

Sierra 61's first flight of the day on October 10, 2003, originated from WC 509 at 0832, with the pilot reporting fuel-on-board to be "2 hours and 05 minutes," while en route to HI 330. The flight arrived at HI 330 at 0854. The second flight of the day departed HI 330 at 1006 with two passengers, and was destined for WC 509, with an estimated time of arrival at 1030. At 1009, the pilot reported the fuel-on-board to be "one hour and 35 minutes."

At 1035, Sierra 61 reported to PHI's Communications Center (COMCTR) that it was landing at WC 509. According to a witness located on WC 509, the helicopter was observed, "coming down at a very steep angle from the southeast on the southwest side of the platform. The helicopter started to ascend on a northwestern heading, as he lost sight of the helicopter very quickly due to the heavy rain."

At 1046, Sierra 61 called the COMCTR asking for information and assistance to get out of the weather. Because of the prior 1035 call to COMCTR, PHI's flight follower was under the impression that the helicopter had already landed at WC 509. At 1049, the COMCTR answered Sierra 61 by suggesting that he "just tie down for a few minutes and let it pass you over, and then take off again." Sierra 61 never responded.

Another PHI flight overheard the radio communication between Sierra 61 and COMCTR and suggested that COMCTR call WC 509 to verify that Sierra 61 was actually on the helideck. After verifying that the helicopter was not on the helideck, a search was initiated in the WC 509 area. At 1717, a signal emitted from an Underwater Emergency Position (Pinger) was received by a search boat. At 2100, a PHI hydrophone (device to pick up underwater acoustic energy) was used to confirm the signal from inside the East Cameron (EC) 264 block area. At 1030 on October 11, an oil slick was spotted inside the EC 261 block, approximately four miles northeast of WC 509. After several days of four to eight feet sea conditions and wind of 30 to 40 knots, the location of the helicopter wreckage was confirmed by divers in the EC 264 block on October 12, about 2310. The search for occupants continued until the early hours of October 14, before the last person aboard the helicopter was recovered.

PERSONNEL INFORMATION

The non-instrument rated commercial helicopter pilot, age 61, had been employed by PHI since April 1, 1980, and did not hold any other ratings. At the time of his employment application with PHI, the pilot had accumulated 5,530 hours of helicopter time. Initial completion of helicopter training was received from the armed forces of the Republic of South Vietnam in November 1966.

PHI assigned the pilot to offshore platform WC 509 on August 8, 2002, and he commuted from PHI's Sabine Pass base (SABN), near Sabine Pass, Texas. He started his last 14-day work schedule on October 2, 2003. The Flight and Duty Time Log shows that on October 9, 2003, the pilot reported for duty at 0630 at Sabine Pass and ended his duty day on WC 509 at 1700, with 3:05 hours of flight time. On the day of the accident, the pilot reported for duty on WC 509 at 0630.

According to company records provided by PHI, the pilot had accumulated a total of 18,913 hours, with 12,416 hours in the Bell 206 model. Federal Aviation Administration (FAA) records indicate that the pilot did not have any prior accidents, incidents, or violations. He had accumulated 67 hours of flight time in the accident make and model in the last 30 days. The pilot held a valid FAA second-class medical certificate issued February 11, 2003, with the restriction of "Holder shall posses glasses for near and intermediate vision."

On April 4-5, 2003, in accordance with 14 CFR 135 recurrent and proficiency check training, the pilot satisfactorily completed PHI's Bell Helicopter (BH) 206 VFR recurrent training requirements. The training included groundschool operational requirements and two flight training device (FTD) module periods (total 3:00 hours). FTD period one consisted of normal and emergency procedures, including weather minimums, passenger briefings, and heliport requirements. FTD period two included recognizing and avoiding severe weather situations, inadvertent entering and escape from IMC, emergency egress, and ditching procedures.

AIRCRAFT INFORMATION

The 1989-model Bell 206L-3, serial number 51301, was equipped with a 650-horsepower Rolls-Royce Allison 250-C30P turboshaft engine, serial number CAE 890094S, a two-bladed main rotor system, and a two-bladed tail rotor. The 12 month/1200-hour airframe inspection was completed on January 11, 2003, with 12,902.25 hours. The helicopter completed 300-hour and 150-hour maintenance inspections, in accordance with its approved aircraft inspection program, on October 5, 2003, with total aircraft time of 13,669.45 hours. From PHI's aircraft status report, the helicopter had accumulated a total time of 13,692.40 hours on October 9, 2003.

The engine had completed the 150-hour and 400-hour inspections on September 26, 2003, with total time of 10,902.30 hours. On October 9, 2003, the recorded total time on the engine was 10,961.35 hours.

A review of the airframe and engine records did not reveal any open discrepancies or anomalies.

Log sheet maintenance discrepancies were reviewed for the last 45 days, including corrective maintenance actions. The last two days of log sheets were aboard the helicopter and were not recovered. No open discrepancies or unusual events were noted. There were no deferred maintenance items using the policies and procedures of the Minimum Equipment List (MEL) and Configuration Deviation List (CDL), during the last 45 days up to October 8, 2003. The computerized listing for major repair and alterations was examined, and no discrepancies were noted.

Weight and Balance control procedures were approved by the FAA, with an effective date of April 4, 2002. These procedures by which either actual or approved average baggage, passenger, and crew weights may be used are in the operator's control program. N81671 was weighed on April 6, 2003. Total empty weight was 2,762 pounds, longitudinal arm 129.9 inches and moment 358721.2, lateral arm 0.07 inches and moment 201.84. A weight and balance form sheet was computed by PHI for the NTSB's investigator-in-charge (IIC), with estimated weights for crew, passengers, cargo, and fuel for determining center of gravity (CG). The actual seating of passengers aboard the helicopter was determined by witness statements. The result of the computation was that the aft, forward, and lateral CG range were within gross weight limits.

The helicopter was not equipped with a cockpit voice recorder (CVR) or flight data recorder (FDR), nor are they required.

METEOROLOGICAL INFORMATION

During an on-site evaluation of PHI's Communication Center (COMCTR) by the NTSB investigator-in-charge (IIC), the following weather service capabilities were noted: tailored weather radar graphics showing oil platforms with near real-time radar echoes overlaid on the display; all pilots start the day with a weather briefing from the COMCTR; the center has satellite radar data that is displayed every 12 minutes, pilot reports are sent to the COMCTR; the COMCTR has a current list of private, company, and national weather observation sites that are available.

According to the National Weather Service, a trough of low pressure moved from the northeastern Texas coast during the early morning hours of October 10, 2003, and was located in the vicinity of WC 509 when the accident occurred. Scattered very heavy to intense thunderstorms were located along the trough line. A short line of video integrator and processor (VIP), a system used to determine the intensity of precipitation, level 4-5 thunderstorms with maximum tops to approximately 48,000 feet was near WC 509 at the time of the accident. There are no National Weather Service (NWS) weather observation stations in the Gulf of Mexico, however, many of the platforms record weather observations. There were no weather observations in the vicinity of the accident location, but West Cameron 560 platform (WC 560) , located about 16 nautical miles southwest of the accident site and 11 nautical miles southwest of WC 509, recorded at time 1119; wind 160 degrees at 14 knots; visibility 3 statute miles (SM) with rain: sky conditions overcast (OVC) 600 feet; barometric pressure 29.80 inches of mercury.

Other platform and pilot weather observations from the area that were collected by the IIC included:

West Cameron 580

Time: 1023:

Visibility: 6 SM to the south, 3 1/4 - 4 SM miles to the north, with rain.

West Cameron 587

Pilot report (PIREP) from LAB 71

Visibility: 2 SM.

Conditions to the north, south, and east were worst.

West Cameron 100

PIREP from LAB 71

Visibility: 3-4 SM.

Ceiling: 1,000 feet OVC.

East Cameron 261

Time: 1129

Visibility: 1/4 SM, with rain/2 inch inches.

Ceiling: 400-500 feet OVC.

Green Canyon 184

Time: 1016

Wind: 140 degrees at 20 knots

Visibility: 5 SM, with rain.

Ceiling: 1,300 feet OVC.

Temperature/Dew Point: 27 degrees Celsius and 24 degrees Celsius.

Seas: 6-8 feet.

High Island 582

Time: 1210

Visibility: 1 SM, with rain and fog.

Seas: 2-4 feet.

High Island 350

Time: 1121

Visibility: 1 SM, with rain.

Ceiling: 400-500 feet OVC

High Island 264

Time: 1121

Wind: 240 degrees at 8 knots.

Visibility: 1/4 - 1/2 SM, with rain

Ceiling: 100 feet OVC.

A pilot report at 1020 gave the visibility as 1/2 SM, with rain.

COMMUNICATIONS

On October 10, 2003, the PHI communications center (COMCTR) received the following radio communication transmissions from N81671 operating with the call sign of Sierra 61:

At 1009.00: Sierra 61 transmitted; "High Island Sierra 61."

At 1009.13: COMCTR transmitted; "Sierra 61."

Sierra 61 transmitted; "61 off of High Island 330-West Cameron 509 about three zero, with 3 at 3 plus...ah 1 plus 35."

COMCTR transmitted; "Sierra 61."

At 1035.12: COMCTR transmitted; "Sierra 61, High Island."

Sierra 61 transmitted; "Sierra 61."

COMCTR transmitted; "Yes sir, you need some more time?"

Sierra 61 transmitted; "Yes, a little bit more, we run into the rain now, and just trying to get out."

At 1035.37: COMCTR transmitted; "OK, do you want me to add about 10 more minutes to your ETA?"

At 1035.50: Sierra 61 transmitted; "Ok, you can show me landing now."

COMCTR transmitted; "Ok sir, we got you landing."

At 1046.24: Sierra 61 transmitted; "High Island Sierra 61."

COMCTR transmitted; "Sierra 61."

Sierra 61 transmitted; "Yea, we thought we could see that we couldn't get there, so. So we might adverse weather now and you can try to get me out here. (Unintelligible)"

COMCTR transmitted; "Yes, I had gotten you sir, had you landing at WC 509, yes sir."

Sierra 61 transmitted; "Not yet, I thought I fly over there and we try to land and couldn't get there."

COMCTR transmitted; "Oh yes, but you had came up. I had called you and then there was a pause and you came back up and you were getting out of the rain and you were landing right then, that was at 10:33."

At 1047.23: COMCTR transmitted; "Have you got another plan Sierra 61, or you just wanted to make sure I copied your landing?"

Sierra 61 transmitted; " (unintelligible) Yes, I try to get...happy to get out of the weather right now."

COMCTR transmitted; "Oh OK, alright, I copy you now, standby."

At 1047.52: COMCTR transmitted; "Sierra 61, where would you like to go at from West Cameron 509?"

Sierra 61 transmitted; "Yea, anywhere we can get out of the weather."

COMCTR transmitted; "OK, alright."

At 1048.49: COMCTR transmitted; "OK, Sierra 61, after carefully looking at the radar and the map, your only alternative would be to go South, but if you go South, it will hit you again because it's moving in that direction. What I suggest is you just tie-down for a few minutes and let it pass you over, pass you over, and then you take off again.

At 1049.23: COMCTR transmitted; "Sierra 61 did you copy."

At 1049.46: COMCTR transmitted; Sierra 61, you still up High Island?"

No further radio transmissions were received from Sierra 61. Sierra 61 also never communicated with the WC 509 platform.

AERODROME INFORMATION

The Gulf of Mexico is divided into block areas (3 statute miles long and 3 statute miles wide), for oil/gas lease identification, and according to information from Helicopter Association International (HAI), there are over 5,500 offshore production platforms along the coastline of several states and into the Gulf. Inside block area West Cameron 509 is a large gas production platform called WC 509 (latitude 28 degrees 25.660 minutes North, longitude 93 degrees 01.892 minutes West), which is approximately 80 miles south of Cameron, Louisiana. There are two helidecks associated with WC 509. One is located on top of the living quarter's platform, and is approximately 50 feet long and 50 feet wide. The other helideck is located on top of the production platform, and is approximately the same size. The platforms are connected by a walkway about 300 feet apart. The WC 509 complex is where Sierra 61 normally spends its nights, secured to the helideck of the platform. The helicopter is staffed by one pilot who works 14 days on, and then has 14 days off. Approximately every three days, the pilot will fly the helicopter to PHI's Sabine Pass base, near Sabine, Texas, for a general maintenance inspection and any scheduled maintenance requirements needed. For those days spent offshore, the pilot conducts daily maintenance inspections of the helicopter.

WRECKAGE AND IMPACT INFORMATION

The wreckage was located inside block area East Cameron 264 (EC 264) at latitude 28 degrees 27 minutes 49.3 seconds North, longitude 92 degrees 55 minutes 44.5 seconds West, submerged in approximately 165 feet of water. The location is approximately five miles northeast of WC 509. The main fuselage body of the helicopter came to rest on its left side, with the landing gear skids and tail boom section located approximately 20 feet away. Other pieces and parts were located up to 120 feet away by divers. A "Remotely Operated Vehicle (ROV)," essentially an underwater robot with photo capability, also provided critical information about wreckage locations. The depth of water varied from 150 to 180 feet, and wreckage recovery occurred over several days where items were moved onto a boat and transported to shore. The wreckage was then hauled by truck to the PHI facilities at Lafayette, Louisiana for further examination.

Examination of the wreckage by the NTSB IIC, with representatives from the FAA, PHI, Bell Helicopters, INC., and Rolls-Royce Corporation. The examination revealed the tail boom separated from the fuselage, the engine remained attached to the fuselage, and the hydraulic assembly remained attached to the roof and beam assembly. The float bags were not inflated. The main rotor blades remained attached to the main rotor blade hub assembly. The instrument panel was recovered as a single component with many of the instruments missing, including the dual tachometer, engine oil temperature/pressure gauge, torque meter, transmission oil temperature/pressure gauge, turbine outlet temperature gauge, fuel quantity gauge, gas producer tachometer, and fuel pressure/DC load meter. All critical components were accounted for, and flight control ends remained attached to recovered surfaces. Control and drive continuity were established aft of the oil cooler drive shaft to the tail boom and tail rotor. Damage conditions made it impossible to determine control continuity throughout the fuselage area.

The crew and passenger compartments were fragmented into multiple pieces. The fuel valve cutoff switch was in the "ON" position, with the installation modification of a locking gate. The integrity of the fuel system was compromised during impact, and there was not any fuel found in any of the lines or components up to the airframe fuel filter. However, fuel was found in the airframe fuel filter and in the line that is attached to the fuel nozzle. The two electric fuel boost pumps were separated from the fuselage.

The engine sustained impact and salt-water corrosion damage. All engine mounts were bent and/or broken. The fuel pump, power turbine governor, and fuel control unit driveshafts and splines were intact. The accessory gearbox exhibited large areas of corrosion, which had penetrated the case. The low and high pressure compressor sections of the engine would not rotate by hand. The compressor impeller exhibited heavy rub and friction bluing on all blades. The impeller shroud exhibited heavy rub in the 6 to 12 o'clock quadrant that penetrated into the base metal. The diffuser scroll turning vanes were intact and in place. The spur adapter gearshaft was intact, but heavily corroded. All turbine wheels were intact and unremarkable. The turbine to compressor coupling was intact, but heavily corroded. The 1st, 2nd, and 3rd stage nozzles were intact and unremarkable. The 4th stage nozzle exhibited deep rotational scoring in the blade paths of the 3rd and 4th stage turbine wheels, including impeller shroud. There were no failed parts or components noted on the engine assembly during the examination.

The transmission and main drive system sustained impact damage. The transmission was decoupled from the engine, with fractured control tubes extending to the main rotor assembly. The nodal beam assemblies also sustained impact damage. The right forward transmission support link was fractured about five inches from the attaching point. The right side elastomer flexible assembly was separated from its forward bearing. During the examination, the mast was removed from the transmission; drive continuity was confirmed, as the drive spline was hand-rotated.

Both main-rotor blades were fractured by upward bending, and exhibited chordwise wrinkling throughout the spans, with leading edge damage on the blades. One blade fractured about 3/4 of its length outboard, and the other blade fractured just outboard of the attach doublers. All primary control components sustained substantial impact damage, with fractured surfaces displaying 45-degree shear lips. The collective sleeve, swashplate, and support were still attached to the mast above the transmission. The throttle was found in the full open position on the collective.

At PHI's hydraulic shop, both cyclic servos and the collective hydraulic actuators were tested. The right cyclic and middle collective extended and retracted when hydraulic pressure was applied. The left cyclic was slightly bent, prohibiting full extension and retraction when hydraulic pressure was applied.

The tail boom sustained substantial damage and was separated from the fuselage. The fracture surface was located aft of fuselage station 204.9, forward of the tail boom/fuselage attaching point. The number one driveshaft segment displayed a fracture on the forward end that was consistent with torsion shearing. The second segment driveshaft had a bolt missing from one side of the flexible coupling, with no visible damage or scoring in the coupling area. The left horizontal stabilizer was separated about one foot outboard of the attachment point. The right horizontal stabilizer sustained minor damage. The vertical fin sustained damage at both the upper and lower sections, with the bottom section split at the seam.

The tail rotor gearbox fairing displayed a significant impact signature on the left upper side. The tail rotor control head and control assembly appeared undamaged. The controls remained connected and moved freely. When the control tube inside the tail boom was moved, there was a corresponding movement of the rotor blades. The tail rotor blades rotated freely; however, there was substantial leading edge damage to both blades.

The field examination did not identify any preimpact airframe anomalies.

MEDICAL AND PATHOLOGICAL INFORMATION

On October 14, 2003, an autopsy was performed on the pilot at the County of Galveston Medical Examiner's Office, Texas City, Texas. The report indicated no evidence of any preexisting disease that could have contributed to the accident.

Toxicological testing on the pilot was performed by the FAA's Civil Aeromedical Institute (CAMI) Forensic Toxicological and Accident Research Center, Oklahoma City, Oklahoma, for carbon monoxide, cyanide, volatiles, and drugs. There was no carbon monoxide or cyanide (values are confirmed by FAA) detected in the blood, and no drugs (list and values are confirmed by FAA) detected in the kidney.

SURVIVAL ASPECTS

The cockpit and cabin area sustained major impact damage and was mostly fragmented. The seatbelt fastening components examined were all fastened to its respective mating end or were hanging loose. The configuration of two of the seatbelts did not allow for determination of whether they were in use at the time of the accident. Divers cut the pilot's seatbelt to remove the pilot from the wreckage.

The landing gear (skid type assembly) was relatively intact, with the floats still stowed and partially folded inside the remains of the enclosure packs. The pressure gauge and regulator that were attached to the float bottle were damaged, with the pressure gauge indicating zero.

FIRE

There was no evidence of smoke or fire aboard the helicopter.

TESTS AND RESEARCH

The automated data acquisition and engine control platform, "IntelliStart System," part number DPU-A-010-1, was removed from N81671 by the IIC and sent to the manufacturer, Altair Avionics Corporation, Norwood, Massachusetts, on October 15, 2003, for download and readout. However, because the last engine-run ended suddenly and there was a system power failure, the unit did not have time to calculate, log, and file a complete run.

Downloaded information included:

Note:

(1) There was a slight local time discrepancy between COMCTR communications and the recorded engine-run time.

(2) An index number is a reference set by the operator to note and record specified parameters or exceedance events.

A. The last recorded engine start time began at 08:20:58 on October 10, 2004, and lasted 28 minutes and 33.86 seconds.

B. The next event detected was at 10:27:35.85, engine torque (130.2980%) exceeded index 8 for 4.88 seconds.

(Index 8 records a torque exceedance above 105% for 4.88 seconds, actually 130.2980%).

C. The next event detected was at 10:27:35.89, engine torque (130.2980%) exceeded index 9 for 12.69 seconds.

(Index 9 records a torque exceedance above 100% for more than 5 seconds, actually 12.69 seconds).

D. The next event detected was at 10:27:41.71, engine torque (125.2063%) exceeded index 8 for 5.85 seconds.

(Index 8 records a torque exceedance above 105% for 5.85 seconds, actually 125.2063%).

E. The last event detected was at 10:38.37.05, where (N2) exceeded index 2 and went to 105.4556% for 2.92 seconds.

(Index 2 records N2 going above 103% to 105.4556% for 2.92 seconds).

Power was removed from the system at 10:38:45.

ADDITIONAL INFORMATION

The wreckage was released to the owner's representative on October 15, 2003.

ORGANIZATIONAL AND MANGERIAL INFORMATION

The operations specifications are issued to Petroleum Helicopters Inc., with Air Carrier Certificate Number HEEA617E. The certificate holder is authorized to conduct operations under the following other business names: Heli-Tours, Inc., International Helicopter Transport, Inc., and PHI Aeromedical Services. The Air Carrier Certificate, which included the standards, terms, conditions, and limitations contained in the FAA approved Operations Specifications (Parts A, B, D, E, and H) were reviewed. All management positions of the 14 CFR part 135 certificate holder were fulfilled as required by part 119.65, including the Director of Safety, who reported directly to the President and Chief Executive Officer of the corporation.