NTSB Identification: DFW05MA230
Nonscheduled 14 CFR Part 135: Air Taxi & Commuter
Accident occurred Tuesday, September 06, 2005 in Gulf of Mexico, TX
Probable Cause Approval Date: 04/28/2009
Aircraft: SIKORSKY S76, registration: N90421
Injuries: 5 Serious,7 Minor.
NTSB investigators traveled in support of this investigation and used data obtained from various sources to prepare this aircraft accident report.
About 18 minutes into the flight, the No. 1 (left) engine fire warning light illuminated in the cockpit, followed by several additional engine warnings and visible smoke in the cockpit and passenger compartment, according to crew and passenger interviews. After the fire and smoke indications, the helicopter lost power to both engines, and the flight crew executed a forced landing into the open waters of the Gulf of Mexico. The helicopter wreckage was located, and the cockpit voice recorder (CVR) was recovered shortly after the accident; however, efforts to recover the remainder of the wreckage were suspended due to an approaching hurricane. The wreckage could not be located following the hurricane; therefore, the cause of the in-flight fire warnings and the loss of power to both engines could not be determined.
After the first engine fire warning, CVR evidence revealed that, contrary to their training and the helicopter manufacturer's guidance, neither pilot acknowledged the fire warning, called for a checklist, or verbalized a plan of action. According to the Sikorsky S-76A Flight Manual, the emergency procedures for responding to an engine fire warning include pressing the fire warning light, establishing safe single-engine flight airspeed (76 knots), fully retarding the affected engine's illuminated T-handle (a handle located on the engine throttle quadrant above and in front of the pilots, which, when pulled, stops the flow of fuel to that engine and releases a fire suppressant), and, if necessary, selecting and activating the fire extinguishing system. The pilots, who had been on duty for more than 10 hours and had completed 13 landings that day, only completed the first step during the 2 minutes before impact with water; therefore, the pilots failed to follow emergency procedures in response to the engine fire warning. National Transportation Safety Board performance calculations indicated that, if the pilots had immediately completed the first three steps in responding to the No. 1 engine fire warning, as required, they may have been able to maintain single-engine flight to a suitable landing location on an off-shore platform before the No. 2 engine failed.
The investigation revealed additional flight crew performance deficiencies. For example, although the first officer transmitted a "mayday" call before the second engine failure and about 1.5 minutes after the first warning indication, he did not provide essential information needed to obtain emergency assistance. He also did not inform the passengers that they were executing a forced landing into the water. Before flight, the flight crew did not provide the required preflight passenger safety briefing, which would have included instructions on how to retrieve and inflate a liferaft; the passengers did not retrieve either of the two liferafts. All of these performance deficiencies are consistent with the known effects of situational stress (in this case associated with the emergency) and fatigue (associated with a long, demanding day of flying), both of which likely degraded the pilots' performance.
The flight crew did not file a flight plan with either the Federal Aviation Administration (FAA) or HHI, contrary to company procedures. Although Houston area air traffic control (ATC) facilities were monitoring emergency frequencies, controllers did not hear the distress call because the helicopter was well outside and below ATC radio coverage when the transmission was made. Commercial and military pilots in the area reported hearing the distress call to various ATC facilities; however, none of the reporting pilots could provide any additional information about the distressed aircraft because the first officer had only stated, "mayday ... Houston 421... going in" and did not provide a location or type of emergency.
At the time of the accident, neither HHI's communication network nor Gulf of Mexico offshore cellular towers were functioning as a result of Hurricane Katrina, and the company did not provide an alternate means for its pilots to communicate with base operations. Instead, HHI suggested that pilots use their personal satellite cell phones or request assistance from oil platform personnel to relay information to base operations. The accident pilot reported that he was reluctant to use his personal satellite cell phone because HHI would not reimburse him for the calls.
Regardless, flight crews were expected to contact an FAA automated flight service station if they could not contact base operations, and the accident flight crew did neither. If the accident flight crew had been reporting in every 15 minutes, as required by the company's OpsSpec, the HHI radio operator would have been alerted when the accident pilots missed a reporting time and HHI would have had more information about the accident location. HHI did not report the overdue helicopter to the FAA until almost 2 hours after the flight was expected back at homebase. As evidenced by this accident, HHI did not ensure that its pilots were adhering to flight-following procedures and did not have adequate procedures for reporting overdue flights; both of these deficiencies also delayed the initiation of the search and rescue efforts.
As a result of this accident and others, the Safety Board recommended to the FAA that "all offshore helicopter operators in the Gulf of Mexico provide their flight crews with personal flotation devices equipped with a waterproof, 406 megahertz personal locator beacon equipped with an enabled global positioning-system, as well as one other signaling device, such as a signaling mirror or a strobe light." (A-07-88) The 7.5 hours that the passengers spent in the water exposed them to hypothermia-inducing conditions, and the lack of a 406 megahertz personal locator beacon and another signaling device delayed their rescue. The recommendation was classified "Open-Acceptable Response," on July 25, 2008, pending the results of FAA meetings with industry and possible issuance of rulemaking.
As early as 2003, the FAA was aware of safety deficiencies at HHI, including lack of passenger safety briefings and inadequate flight-locating procedure training for dispatchers. In February 2005, the newly assigned principal operations inspector recorded HHI's lack of adherence to flight-locating procedures. Despite his efforts in August 2005 to suspend operations at HHI until the deficiencies were addressed, the Houston flight service district office manager gave HHI an extension on the morning of the accident because of the urgent need for helicopter services following Hurricane Katrina. After the loss of communications following Hurricane Katrina, the FAA improperly assumed that HHI had developed an alternate method of communication to comply with flight-following requirements because a survey of some Gulf operators revealed that they had started using repeater aircraft or satellite telephones. However, HHI had not done so. In addition, the FAA principal maintenance inspector failed to inspect all of the company's PFDs (eight of which had unapproved repairs) and repairman's manuals (which were out of date). The FAA's inadequate surveillance of HHI's operations and maintenance over an extended time contributed to the persistence of an unsafe corporate culture at HHI, which led to a disregard for passenger briefings, improper handling of emergency situations, and lack of flight-following and fostered noncompliance with regulations.
The National Transportation Safety Board determines the probable cause(s) of this accident to be: The pilots' delayed response to the No. 1 engine fire warning and the loss of power to both engines, which occurred for undetermined reasons. The pilots' delayed response was most likely due to stress and fatigue. Contributing to the delay of the initiation of search and rescue operations were the pilots' incomplete "mayday" call, the pilots' and Houston Helicopter, Inc.'s (HHI's) noncompliance with company and Federal Aviation Administration (FAA) flight-following requirements, and HHI's inadequate communications contingencies and procedures for reporting overdue flights. Also contributing to the delay of search and rescue operations was the FAA's inadequate surveillance of previously identified company deficiencies, including HHI's lack of adequate flight-following procedures. This lack of surveillance allowed HHI's corporate culture to remain lax with regard to safety. Full narrative available
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