Super Puma investigation reveals major survivor location snags

Bond Super Puma.JPG

Happily the February loss of a Bond Helicopters EC225 Super Puma in the North Sea was non-fatal, and now it turns out that luckily it was in benign conditions for the survivors. That’s because of three serious and unsuspected phenomena that led to the search operation being much more difficult than you’d imagine in the circumstances. The AAIB reports on them today.

The helicopter, you may recall, descended fairly gently into the sea in darkness, visually observed by individuals on the rig to which it was heading. It floated and the 18 occupants quickly got into the liferafts. Between the aircraft, the liferafts and the individuals they had plenty of locator beacons. Nevertheless, it took a 27 minute search to find the survivors.

Here’s why.This is the problem as far as the AAIB can establish. First theautomatically deployable crash position indicator on the helicopterfailed to release and didn’t transmit a signal. That aspect is stillunder investigation and the AAIB doesn’t venture a view as to how thathappened. It’s obvious that in more serious circumstances that alonecould be a crucial issue.

But there’s more. In the helicopterthere were four locator beacons – known as personal locator beacons forindividuals and emergency locator transmitters (PLB/ELT) on liferafts.One on each pilot’s lifejacket and one on each liferaft – all of thesame design.

They broadcast a signal on 406MHz to theCospas/Sarsat satellite-based international SAR organisation, and theybroadcast homing signals on the 243MHz and 121.5MHz internationaldistress frequencies. You can also talk on the distress frequencies.But it’s very important that the the telescopic antennas are extendedand in the vertical position for maximum efficiency.

Cleverly,if they’re close together then one of the beacons automatically becomesthe master and the others stay in standby mode, partly to save batterypower and partly to avoid confusing searchers.

But thepassengers were also wearing wristwatch-type personal locator beaconswhich are legal and in routine use, but not formally certificated bythe airworthiness authorities.  Those, it now turns out, will alsosuppress the PLB/ELT signals. But their own signal is very much weaker- a theoretical 5 miles, but in practice less, compared to up to 40nmfor the PLB/ELTs.

Furthermore, one of the four PLB/ELTs – mounted on oneof the liferafts – did not activate and was not recovered. It’s notknown why it didn’t activate.

And in any case it’s emerged thatthe crew didn’t actually know they had to correctly orient the beaconsor that they even had extendable antennas.

The upshot was thatdespite there being three functioning ELT/PLBs in use, SAR aircraft didnot receive any signal on 121.5MHz or 243MHz. And no voice signals werereceived either. In the end a faint 121.5MHz signal was detected,probably from a wristwatch beacon.

The AAIB, as you can read inthe full report, wants CAA and EASA reviews of the whole sorry saga andsome pretty rapid action on training.

Who’d have imagined.

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