The Air Accident Investigation Unit (AAIU) has recommended that CHC Ireland reviews all route guides used by its helicopters in light of the Rescue 116 crash which killed four air crew.
The preliminary report by the AAIU into the crash, which claimed the lives of Capt Dara Fitzpatrick (45), co-pilot Capt Mark Duffy (51), winch operator Paul Ormsby (53) and winchman Ciaran Smith (38), highlights the fact that the crew were using a prepared route.
The 38-page preliminary report indicates that a chain of events – some still to be investigated – led to the fatal crash off Blackrock island, 13km west of Blacksod lighthouse in north Mayo, in the early hours of March 14th.
The route guide appears to have lacked vital information on the north Mayo coast when the Dublin-based Irish Coast Guard helicopter crew was tasked to provide “top cover” to their Sligo counterparts for a medical evacuation.
An initial request for Air Corps “top cover” had been turned down as staff were not available.
The helicopter was owned by CHC Helicopter, which employs the air crew on a contract to the Coast Guard.
The AAIU says that the CHC review should focus on improving information on “obstacle heights and positions, terrain clearance, vertical profile, the positions of waypoints in relation to obstacles and enhanced ground proximity warning systems (EGPWS) database terrain and obstacle limitations”.
The fact that none of the four crew were located by satellite beacons is also explored in the preliminary report.
The crew’s beacons had been installed in the same pouch as the GPS antenna, as per a service bulletin issued by the lifejacket manufacturer.
However, the report notes the beacon manufacturer recommended a minimum separation distance of 30 centimetres between the GPS antenna and beacon to ensure the beacons functioned.
It recommends that the manufacturer of satellite locator beacons on Mk 44 lifejackets used by the search and rescue air crew should review “the viability of the installation provisions and instructions”.
The report found that the helicopter “pitched up rapidly” and collided with the western end of the island in its final seconds, with the final recorded words from co-pilot Capt Mark Duffy – “we’re gone”.
The Dublin-based Sikorsky S-92, had flown west of the Mayo coast to turn and made an approach into Blacksod lighthouse on the mainland when it collided with Blackrock lighthouse 13km to the west.
The pilots were relying on a programmed navigational route for Blacksod, which should have assisted their approach.
A separate enhanced ground proximity warning system (EGPWS), which is not to be relied on for navigation but does provide an alert in an emergency, did not have co-ordinates for Blackrock programmed into it.
The failure of this system is the last link in a chain of events which led to the fatal crash, and which the AAIU aims to address in its final report.
The preliminary report notes that the cockpit voice recorder recorded Capt Fitzpatrick “commenting to the other crew members on a number of occasions that it had been a substantial period of time since she had previously landed in Blacksod”, and her co-pilot said he had not been there recently.
The helicopter began a descent from its cruising altitude of 4,000 ft, the undercarriage was extended and speed was 75 knots before impact.
The report says the cockpit voice recorder indicates the co-pilot was using the weather radar to identify terrain features.
The radar altimeter called out “altitude, altitude” some 26 seconds prior to initial impact, while one of the winch crew warned of an island, probably through the use of the infra-red camera, approximately 13 seconds prior to the initial collision.
Capt Fitzpatrick was the first confirmed casualty, after she was recovered from the sea by the RNLI Achill lifeboat and flown to Mayo General Hospital where she was pronounced dead.
After faint signal from the aircraft’s “black box” recorder was picked up onMarch 15th , the main helicopter wreckage was subsequently located off Blackrock island in 40m of water on March 22nd.
The body of co-pilot Capt Mark Duffy was recovered by a Naval Service diving team on March 26th, but extensive searches have so far failed to locate the two winch crew.
The AAIU ruled out “mechanical anomalies” in the aircraft on April 1st, after “initial analysis” of data from the “black box,
