Question for the GLEX-drivers, please.

[Doodlebug]

Gents,

The 5 different serial numbers I've flown have all exhibited the tendency to 'creak and settle' as the cabin does its thing, most of the odd noises occurring on the way up through the twenties. So this is n o t what I'm about to ask about, I know the 'normal' groaning the airplane does.

We've now had a total of 3 loud 'bangs' in the cruise, all in the last 6 weeks or so. No, not the door-slamming-in-the-galley type of thing, either, I mean LOUD, I doubt I would be able to manufacture this level of decibels given any door to have a go at. In fact the last one, yesterday, happened when we ferrying pilots-only, so I know it's not Madame in that mood. Needless to say we're developing nervous twitches and are continuously eyeing the masks.

Guys, seriously. We have NO idea where this is coming from, and the Spanners just get that remote look in their rolling eyes when we ask. Gunshot-loud, eminates and reverberates from everywhere, no discernable indications of anything amiss on any instrumentation whatsoever. No sign of anything giving on any door or window or hatch, nothing.

Any ideas? Running out of underwear here! :uhoh:

Bug

[doubleu-anker]

Never make a test pilot that chap.! What?!

[CL300]

APU was ON and IAS > 300 Kt ?

[ramble on]

Perhaps you could try the main entry door - some movement or settling with cabin pressure differential increase may be causing these noises and having the door lubricated (or possiby the seal - I dont know the GLEX) may help.
Rgds RO

[Doodlebug]

Thanks CL and ramble, also for the PM.

No, APU was off every time, doing .82 to .85 in the low forties.

We did have some corrosion worked on on one of the steps, but this had nothing to do with the seating of the door. (apparently!) Will ask the techs to look at it, though.

[brakechute]

I expect you have probably checked but the only loud bangs I ever got in a GLEX were from the handrails falling out of the original (and crap) restraining clips. I think there is an SB to rectify this, so if you have had it done ignore this, if not I hope this is of some help.

[Captain Bug Smasher]

Doodlebug,

Heads Up, set you a PM

CBS

[Global Warrior]

Could it be floor plates buckling due to pressurization......... happens in the Challenger as well

[Doodlebug]

Hi GW,

I know the buckling you're referring too, all the GLEX's I've flown did it. No, this is something else. Way louder! I've looked at the suggestions mentioned above, no luck. Did notice some abrasion on the left-hand side of the door-frame as you enter, but this is probably just due to the rigging of the door. Currently waiting in suspense for the next nerve-shattering 'bang' to occur, been quiet for a while now.. :confused: Thanks for the input, though!

[exjet]

You could be refering to a sound (or sounds) more comparible to a 'dull thud'. Similar to the 'cladding' in the cockpit but eminating from pax walking in the cabin. It is more pronounced with the cabin door closed.

[Flasharry]

Hi There,
We had a similar incident with a new Learjet once. Turns out that the water vapour in the coalescer sock was freezing and causing a pressure buildup, the loud bang we experienced was air bypassing the sock. Like you say, bloody loud and scares the s**t out of you.

Don't know about the GLEX, but sounds similar.

Cheers.

[formulaben]

I can't say how many times I've heard "expansion" noises coming from the airframe, but each and every time I've never been comfortable with it. Good luck with your search, but I fear that it's the same thing I've been seeing in my experience (CE-500 series, CE-750, IAI-1125 and other misc aircraft.) Keep the O2 at the ready, but don't lose any sleep over it unless you're positive it's something other than the above.

[Doodlebug]

Thanks for the thoughts, gentlemen!

I'll have the opportunity to speak with the lads at Bombardier themselves, shortly, and will come back to you with what they advise.

(we HAVE been having fun with the potable-water systems. Might be that some kind of freezing, etc. is playing a role)

Regards,

Bug

[specialbrew]

Ah.... the notorious Global water system.... a legendary design ! Dont you just love it.....NOT!:rolleyes: