Signal interference and antenna errors hamper North Sea rescue

Casualties unknown • 500 metres south of ETAP platform, North Sea, GB

A search for a downed Eurocopter EC225 LP Super Puma in the North Sea was significantly delayed by signal suppression from passenger wrist-worn beacons and improper antenna deployment.

What happened

On 18 February 2009, a Eurocopter EC2CO225 LP Super Puma, registration G-REDU, was performing a commercial passenger flight near the ETAP oil production platform in the North Sea Central Area. During the night approach to the platform, observers on the ETAP installation witnessed the aircraft strike the sea surface.

Following the impact, the helicopter remained buoyant, allowing the crew and 16 passengers to evacuate into two liferafts. While the crew successfully activated several emergency locator units, the subsequent search and rescue operation faced significant difficulties. Although the aircraft's externally mounted Crash Position Indicator failed to deploy, the occupants were eventually rescued, though 3 passengers sustained minor injuries.

The investigation

The investigation examined the functionality of the various emergency signaling devices on board, including the aircraft's Crash Position Indicator (CPI) and several hand-portable locator beacons. It was noted that passengers were equipped with Wrist Watch Personal Locator Beacons (WWPLBs) designed to alert authorities if a wearer falls overboard.

Investigators also looked into the deployment of the antennas on the TechTest 500-12Y ELT/PLB units. It was discovered that while the antennas were pivoted toward a vertical position, the telescopic upper sections had not been extended by the crew, who were unaware of this requirement.

Findings

  • The search for the liferafts was delayed by approximately 27 minutes due to the weakness of homing signals and environmental factors like fog and darkness.
  • The presence of the WWPLBs adjacent to the TechTest 500-12Y ELT/PLBs inhibited the more powerful emergency signals on the 121.5 MHz and 243.0 MHz frequencies.
  • The failure to extend the telescopic section of the antennas on the ELT/PLB units reduced the broadcast strength and prevented rescue aircraft from receiving voice communications from the survivors.

Safety action

  • The Civil Aviation Authority is advised to review the use of non-certificated radio location devices in commercial transport helicopters.
  • Manufacturers of ELTs/PLBs are recommended to provide clearer instructions regarding antenna deployment on the device body.
  • Training for commercial flight crews should be updated to emphasize the correct operation and deployment of all emergency signaling equipment.

Probable cause

The search effectiveness was significantly reduced because the signal from the primary emergency locator units was suppressed by the proximity of passenger wrist-worn beacons, compounded by the crew's failure to fully extend the telescopic antennas on the emergency units.

Frequently asked questions

What happened in the 2009-02-18 Eurocopter EC225 LP Super Puma accident near 500 metres south of ETAP platform, North Sea, GB?

A search for a downed Eurocopter EC225 LP Super Puma in the North Sea was significantly delayed by signal suppression from passenger wrist-worn beacons and improper antenna deployment.

What aircraft was involved and where did it happen?

The accident on 2009-02-18 involved a Eurocopter EC225 LP Super Puma, registration G-REDU , at 500 metres south of ETAP platform, North Sea, GB.

What was the probable cause of the accident?

The search effectiveness was significantly reduced because the signal from the primary emergency locator units was suppressed by the proximity of passenger wrist-worn beacons, compounded by the crew's failure to fully extend the telescopic antennas on the emergency units.

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