Welcome To Zelo Street!

This is a blog of liberal stance and independent mind

Wednesday 23 January 2013

Helicopter Crash – What The Investigation Found

[Update at end of post]

Just three and a half hours after a helicopter impacted the jib of a tower crane at St George’s Wharf, Vauxhall, last Wednesday, the Air Accidents Investigation Branch (AAIB) had a team at the scene. From their thorough research, we now have rather more information on the events leading up to the accident. The AAIB “Special Bulletin” S1/2013 can be read HERE [.pdf].

The Augusta 109 registered G-CRST, and operating under the call-sign of Rocket 2, had taken off (or “lifted”) from Redhill Aerodrome at 0735 hours, had crossed central London, and arrived overhead Elstree Aerodrome at 0749. However, the pilot concluded that conditions were not suitable to attempt landing, and two minutes later he was heading back towards Redhill.

Only at 0756 hours did the pilot ask if Battersea Heliport was open. He suggested to Air Traffic Control (ATC) that he would prefer to divert there. While ATC checked with Battersea, the pilot was asked to hold. The helicopter, which had been heading towards the heliport, turned and headed east over the river towards Vauxhall Bridge (this was not unusual, and he was cleared to London Bridge if required).

What was not usual, though, was that the helicopter’s altitude, which was well over 1,000 feet clear of the Houses of Parliament, had fallen to less than 800 feet when it turned to head back down river. Its altitude fell further, to less than 600 feet Above Mean Sea Level (AMSL), or 200 feet below the level of the tower crane’s jib, before ascending to almost 800 feet on reaching a point abeam of St George’s Wharf.

At this point, G-CRST turned right, which was consistent with the pilot having been informed that Battersea was open, and that his request to divert there had been approved (the right turn would have continued until the helicopter was heading back west towards the Heliport). But it was not high enough to clear the jib of the tower crane, and hence the impact with it.

Why the pilot wished to divert to Battersea is not clear. The helicopter was not short of fuel: there was approximately 500 kilos of Jet A1 still on board at the time of accident. Also unexplained is the disregarded advice of the client – who was to have been collected at Elstree – not to take off in view of observed weather conditions there. And then there was a series of text messages.

The pilot either read or sent nine of these during the course of the flight (a tenth, to him from the operator, remained unread). It’s probable that he decided that he could manage this additional workload and still maintain full control. After all, he was vastly experienced and knew the area well. And, had he not been ordered to hold, he wouldn’t have been anywhere near that tower crane.

Sadly, circumstances conspired otherwise. I’ll watch for further news from AAIB.

[UPDATE 26 January 1850 hours: on the heels of the AAIB report has come a "Safety Notice" from the Civil Aviation Authority (CAA). Its release yesterday is not a coincidence.

Headed "Flight crew distraction", it is addressed to flight operations personnel and pilots. The Introduction includes "Several recent accidents have highlighted the potential for flight crew to be distracted by conducting non-essential activities in the flight crew compartment ... such activities include ... the use of personal wireless communication devices".

Paragraph 2.4, on the potentially critical consequences of losing situational awareness, should also be read and digested, especially the second bullet point, "altitude or course deviations". The helicopter involved in the St George's Wharf crane impact had descended (see above) to less than 600 feet AMSL and around 200 feet below the height of the crane jib. The pilot then gained height but it was not sufficient to clear the jib.

The pilot had also, as I noted above, sent and received a number of text messages during the flight. The CAA Notice is current until the beginning of February next year, and in being addressed to operations staff as well as pilots, is conceding that, in causing distraction to flight crew, it takes two to tango. The operator of that helicopter should take note]

No comments: