Nimrod Age
MadMark
Spanners
My apologies for the delay for getting back to you, but I have had a couple of days holiday and I purposely refrained from seeking out a computer to get logged on to Pprune! Nevertheless, as promised, I have spoken to some of our senior engineers at LHR and discussed the various points you raised, namely the Licensed engineers and also the checks for locating a fuel leak.
Let me explain the licensed engineers point firstly; and as I thought, you are quite wrong in your statement that unlicensed engineers ‘work’ on BA aircraft. They categorically DO NOT work on the aircraft, and for your information AGE (especially as I understand you are leaving the service soon) I am advised that this website will explain it all to you:
http://www.kingston.ac.uk/aircrafteng/licence/licence.htm
One of the chaps I met at LHR said that he was confident that he knew who you were (DG??) He was also at ISK and was going to get in touch with you.
On the business of locating fuel leaks, I am told by our engineers that there are currently a number of ways of locating a fuel leak. (none of which included buckets and soapy water and compressed air!) They involve ‘sniffer’ devices that are fed into the various areas where a leak is suspected and are used to locate the general area of the leak. (http://www.adixen.co.uk/downloads/Extrima-ENG.pdf) see page 2.
Litmus paper is then used to further narrow the exact location down. There is also some measuring equipment that is placed ‘in line’ within the fuel system to confirm firstly that there is a leak. I understand that the system is then pressurized to (I think they said 15lb psi) and a reading is then taken. After a set period of time, the reading is checked again, and if it has dropped then there is a leak. If it hasn’t then the system is OK. There are tolerances, but I don’t remember them. This method also helps in general location, as the pressurized system ‘forces’ out the fuel, thus staining the area of the leak.
(http://www.engineeringtalk.com/news/sis/sis105.html) This report highlights the importance of good leak detection, and in particular take note of the paragraph that states:
‘[FONT='Arial','sans-serif']Soap bubble testing can detect very small leaks allowing the operator to pinpoint the location of a leak. However, the process is highly dependent on the skill and patience of the operator. This can be dangerous if the operator's perspective is limited. For example, small leaks may remain hidden on the reverse side of the component or in a recess, which is a common occurrence in the aerospace industry where components are usually packed into tight spaces. [/FONT]
[FONT='Arial','sans-serif']Sometimes with soap bubble testing, larger leaks do not cause the formation of bubbles; instead, the compressed air blows away the soap solution, and operators frequently fail to observe such leaks.[/FONT]
[FONT='Arial','sans-serif']Conversely, with small holes, the capillary force can be extremely strong. [/FONT]
[FONT='Arial','sans-serif']The result is that liquid that has been sucked into a micro leak by capillary action, cannot be forced out with compressed air, and therefore no bubbles will appear. [/FONT]
[FONT='Arial','sans-serif']Another widely used leak detection method in the aerospace industry is pressure decay, where compressed air is simply injected into a test object, and a decrease in air pressure over time signifies a leak.[/FONT]
So, I can just confirm to you, that the practice of draining the fuel system down and then blowing air through it and listening for whistles, is NOT used on BA aircraft, and I would doubt that it is used on any other major airline.
That is still not to say that I blame you or any of your colleagues for what happened on 230, because I do not. But what you must try to appreciate (and it took me a long time to get my head around this also) is that the RAF is NOT the best at everything it does. It does NOT have the best kit available and does NOT (always) employ the best practices. I would suggest that perhaps you didn’t even know about these other methods of fuel leak detection did you? I am pretty sure that had you known about them, that someone at ISK would have suggested that you get one. But that would mean money, and thereby lies the root of this disaster – lack of money.
Now, and finally, as to whether or not you think I am a Walter Mitty or a real aircraft Captain flying a damned great aeroplane backwards and forwards across the pond with a few hundred pax behind me, I would simply respond by saying that frankly, I really couldn’t care less one way or another. You are free and entitled to make your own decision, and it affects not one thing in my life, it’s entirely yopur call Sirs.
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But please, try to stop taking offence at everything that is said that remotely involves the groundcrew. IMHO they are NOT to blame at all for what happened to 230. The blame lies squarely on the shoulders of the government, then SoS, then CAS, ACAS, AOC, and probably the Station Commander, although I note that he did pass on his concerns up the chain.[/FONT]
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The Winco[/FONT]