A Tale of Two Chinooks

Whether the Government likes it or not, helicopters are on the agenda and regularly on the front page.  In this instance we take a delve into the recent story of the ‘Cut and Shut Chinook Scandal’, which actually isn’t a scandal.  It isn’t actually much of a story, but at the moment it is being used as a stick to beat both the Government and the MOD.

The headlines recently announced that the RAF were operating a Chinook in Afghanistan that was rebuilt using two different airframes.  This was highlighted in ‘The Sun’, which reliably informed us that, ‘The two parts were fused together — a technique often used illegally by dodgy car dealers’ and contrary to the report in ‘The Daily Mail’, both engines were still attached to the airframe as the adjoining photographs clearly testify. On the face of it, the story itself is true, although missing a few vital facts.  One should take stock and note at this point that, dodgy car dealers aside, the processors used to manufacture a 1991 Vauxhall Cavalier and a Boeing Chinook are fundamentally different to say the least.

One, namely the Vauxhall, is made from pressed steel and welded, and was manufactured in a very short period of time.  The Chinook, in sharp contrast, is hand built in a jig using solid rivets and hand-formed sheet magnesium and aluminium; this as you can appreciate takes a significantly longer time compared with the Vauxhall.  Chinooks are also subject to a greater degree of quality control.

The aircraft in question is a Chinook HC.2, registration ZA704.  ZA704, Boeing build number B-834, was manufactured in the USA by Boeing at their Ridley Park Plant, Delaware County, Philadelphia and delivered to the RAF in 1981.  It was subsequently returned to the factory and converted into a HC.2 model, and then redelivered to the RAF around 1993.  On 23rd November 1999 ZA704 had an accident whilst on exercise at Soz, Oman.  Unfortunately whilst carrying out a run-on landing, the rear rotors touched the ground and this consequently ripped off the aft transmission, together with the structural pylon.

Chinook-2

Chinook-3

Rather than send the aircraft back to the manufacturers in the USA, it was decided to repair the aircraft in the UK at Fleetlands, Gosport.  To those that don’t know Fleetlands it is, or at least was, a Royal Navy repair facility that carries out third and fourth line aircraft maintenance.  I understand it has now been privatised and sold to Vector Aerospace.  Fleetlands has a long association with the UK military and their engineers are highly competent at repairing aircraft.  I have no doubts that the repair would have matched any carried out by Boeing.

Having lost its rear pylon it was decided to cannibalise one from another Chinook, ZH257.  The donor Chinook ZH257 was originally a CH-47C, registration AE-520 (Boeing build number B-797) and was captured from the Argentine Army relatively intact following the Falkland’s Conflict in 1982.  It was then used as a ground instruction airframe and was subsequently given a UK military serial number.  As the RAF Chinook HC.2’s are equivalent to the CH-47D, it was necessary to make a number of modifications to the donor pylon prior to attaching it to the recipient aircraft.

Chinook-1

Prior to re-assembly and flight testing the repair was signed off by one of Boeing’s own engineers as they were the Aircraft Design Authority, not something they would have done had there been any doubts about Fleetlands competence.  Following this, it would have been extensively air-tested and subject to alignment checks to ensure the structural integrity of the repair; if it wasn’t, the pilots assigned to fly it would be well within their rights to refuse.  The fact that they have flown it repeatedly since demonstrates their level of confidence in the airframe.  In addition to this the repair would be subject to routine inspection for the remainder of its in service life.  As a comparison, during the Falklands Conflict a Sea Harrier received damage from anti-aircraft fire.  This damage was repaired using a Battle Damage Repair (BDR) scheme as there was little time to develop a manufacturer based scheme.  This aircraft carried the BDR repair for many years until the aircraft was eventually modified to F/A 2 standard; proof that even ad hoc repairs can still have excellent structural integrity.

So to all those deeply concerned about the ’Cut and Shut Chinook’, be rest assured, the aircraft itself is structurally sound.

Another aspect of the story was that it was brought to the attention of the media by Ian Sadler, the father of Jack Sadler who tragically died in Afghanistan, 2007.  Mr Sadler has since campaigned to improve the equipment used by the UK armed forces.  The MOD can be accused of many things, financial incompetence and short-sightedness to name but two, but on this occasion the MOD probably did nothing more than sign the cheque.  Repairs of this magnitude are nothing new and comparable ‘Cut and Shuts’ have been carried out on other types of aircraft.  In conclusion, it was undoubtedly cheaper to repair the aircraft in the UK rather than ship it back to the factory, but this is more to do with standard industry practice as opposed to penny pinching by the MOD.  There are a great many things the MOD need to be taken to task on, especially regarding helicopters (watch this space!), but on this occasion the ‘Cut and Shut’ Chinook isn’t one of them.

 

The link below shows a picture of AE-520 prior to being ‘spliced’.

http://www.airliners.net/photo/Argentina—Army/Boeing-Vertol-CH-47C/0864107/