PDA

View Full Version : Clench Common microlight accident - AAIB Special Report


The Nr Fairy
9th Jun 2006, 04:56
The AAIB have published a special report (http://www.aaib.dft.gov.uk/publications/special_bulletins/s4_2006_pegasus_quantum_15_912__g_byno.cfm) into the accident at Clench Common a few months ago.

Synopsis:
After an uneventful flight, while on the approach to land the aircraft pitched up and rolled to the right. It subsequently crashed into the roof of a barn close to the landing threshold of the airstrip. Swages had failed in four rigging cable assemblies. These four cable assemblies were locally made items, and were not therefore approved by the manufacturer.

bar shaker
9th Jun 2006, 08:01
The maintenance on microlights is very relaxed but certain parts must be factory supplied. These were not.

The cause of this accident has been on the rumour network for some time and I am glad that the AAIB have got the interim report out so soon.

Stafford
9th Jun 2006, 09:04
Bar Shaker

A quick look at the AAIB reports and microlight accidents summary shows it to be a remarkably safe way to go flying. Although a couple of high profile, tragic accidents seem to have exposed one or two loopholes whereby maintenance procedures have fallen between the cracks ?

What is remarkable is that such a young sport has learned fast from the real pioneering days and has remained clear of over regulation, so far, with no significant detriment to overall flight safety ?

I suppose it is difficult to balance the attraction of "simple" microlighting in what used to be very basic machines to the operation and maintenance demands of rather more hi tech microlights now available on the market ?

I hope the two injured flyers are recovering well. It seems that the very experienced instructor had very little control over the machine and they were both (relatively) lucky that the failure occurred where and when it did. As for the cables themselves, I would have thought that making up such cables locally would have been a straightforward procedure for any reasonably qualified person ? I do note the caveat regarding "factory supplied" items though and would tend to think that this action was more for convenience than any minimal cost saving aim ?

Genghis the Engineer
9th Jun 2006, 09:26
I find that report absolutely shocking.

Whilst perhaps my level of knowledge is better than most, I really don't believe that anybody in the microlight world is under any illusion firstly that flying wires (the common name for the cables which failed) are structurally an extremely critical item, nor that the end-swages are the most critical part - subject to considerable inspection and control (often also periodic sample testing).

Of-course it's technically possible to make up replacement cables locally - but you'd obviously need access to the correct cable specifications, the correct type of terminations (swages), not to mention calibrated make-up equipment. Cables are a variable and complex business, particularly if their failure is likely to cause loss of life.

Secondly - why? Clench Common airfield (presumably as this was an instructional airfield, the home of this aircraft) is about 5 miles from Manton. Manton is where the aeroplane was built and product support is still available - it would take a few minutes flying time to nip over to Manton and ask them to fit some new cables. I can only assume that some idiot thought he was saving a few tens of pounds - on a £25k aeroplane...



Having said all that, and thought some much more critical things than I've posted here about whatever criminally insane idiot decided to make their own, clearly substandard, cables up in this way. Bloody well done to AAIB and BMAA for a quick spot of this and flagging it up to the world at large. And thank goodness nobody was killed!

G

Stafford
9th Jun 2006, 09:55
Ghengis

My point exactly, although expressed from a position of engineering ignorance of the criticality of the wires. I am by nature a yellow back striped pessimist and would never dream of making replacement items when a factory supplied (and presumably certicated) item is so readily available.

I wonder how long the suspect wires lasted before failure ?

Genghis the Engineer
9th Jun 2006, 10:17
Ghengis
My point exactly, although expressed from a position of engineering ignorance of the criticality of the wires. I am by nature a yellow back striped pessimist and would never dream of making replacement items when a factory supplied (and presumably certicated) item is so readily available.
I wonder how long the suspect wires lasted before failure ?

Just under 2 hours according to the AAIB report.

G