Qantas jet blows three tires on takeoff

[QF WP]

Actually, I believe they were meant to blow due to a valve being used that sensed when the tires were too hot that they burst rather than turning into flaming tyres and possibly endangerin gthe aircraft further (sorry if it's not the right explanation, it's beyond my capability to explain mechanical things well :shock: )

 

[dot]

Vh-oej Rto
At 122kts on take off EICAS annuciated Take OFF Warning Config Msg Stab fault traced to L/H RVDT stab postion giving incorrect info to the FCU then onto SRM which then dispalyed the warning. Crew Rejected takeoff as any would with a config warning msg. Had the aircraft become airbourne they most probably would have had EICAS warning Stab Trim and unschedule Stab Trim which would have been an ATB. The RTO was carried out as normal, as the aircraft was heavy 380+tonnes the tyres failed from heat build up. Loan parts borrowed, aircraft back in SYD

Some jargon definitions (wikipedia and other sources) :

• EICAS typically includes instrumentation of various engine parameters, including for example RPMhttp://en.wikipedia.org/wiki/Revolutions_per_minute, temperature values, fuel flow and quantity, oil pressure etc
• RVDT’s are used to measure position in aircraft throttle control and flap control systems as well as in fuel control systems for aircraft.
• RTO - Rejected Take Off
• FCU - Fuel Control Unit
• SRM - Structural Repair Manual (but that doesn't make sense in this context - so it may be something else)
• ATB - no idea, sorry

So - to paraphrase hardworker's message - the instruments displayed a warning that indicated a fault with throttle position measurement which was telling the fuel system on the left side of the aircraft (potentially) the wrong setting information.

If we have any pilots out there than can explain the terms I don't understand - feel free to pipe in...

 

[NM]

Actually, I believe they were meant to blow due to a valve being used that sensed when the tires were too hot that they burst rather than turning into flaming tyres and possibly endangerin gthe aircraft further (sorry if it's not the right explanation, it's beyond my capability to explain mechanical things well :shock: )

Yes, that is the case. It is unlikely the tyres "blew". Under heavy breaking, the tyres heat up, which increases the pressure as the nitrogen used to inflate the tyres expands as it heats. Nitrogen is used because it changes less than "air" as the temp changes from very cold (in flight) to very hot (heavy breaking). The tyres are fitted with a pressure relief mechanism that deflates the tyres rather than have them explode leaving bits of broken tyre all over the runway for the next aircraft to collect.

One of the tests that new aircraft types must undertake as part of the type certification process is the rejected take-off test. During this test the MTOW aircraft is accelerated to VR speed and then brought to a halt. It must stand still for a period of time (not sure exactly, but think its something like 5 mins), then must be able to taxi under its own power. In most cases it is expected that during the 5 mins standing many of the tyres will deflate due to the increased pressure resulting from the heat of the braking activity, so being to taxi at MTOW with flat tyres is interesting.

 

[oz_mark]

• ATB - no idea, sorry

Advanced Technology Bomber. Hmm, in the context, maybe, maybe not

 

[globetrekker]

FCU on the 747 is actually the Flap Control Unit
RVDT is the Rotary Variable Differential Transformer, which detects stabilizer angle.

So, looks like it's stabilizer related. That might also explain a pitch up attitude, if it did indeed occur..

The tires would've deflated as a result of the fusible plugs melting. These protect the tyres from exploding due to rapid heat, and thus pressure buildup from the RTO.

 

[moa999]

Wonder if ATB is something like (Abort Turn-Back) given the context of - if the aircraft became airborne,
ie. had it continued accelerating past 122 knots and passed V1 (seemingly 150-160 knots)

 

[dot]

FCU on the 747 is actually the Flap Control Unit
RVDT is the Rotary Variable Differential Transformer, which detects stabilizer angle.

So, looks like it's stabilizer related. That might also explain a pitch up attitude, if it did indeed occur..

The tires would've deflated as a result of the fusible plugs melting. These protect the tyres from exploding due to rapid heat, and thus pressure buildup from the RTO.

Thats the good thing about these sort of Acronyms - there are so many to choose from - at least I got the RVDT right... Fuel vs Flap control unit - pretty significantly different, IMO a good reason not to use these sort of acronyms at all although it seems ingrained in the Aviation and Defense industries. I guess the references to the Stabilizer trim in Hardworker's text should have told me it was more likely to be flap related...

 

[bambbbam2]

Why do people keep writing 'tires' ? Shouldn't it be tyres?

 

[straitman]

Why do people keep writing 'tires' ? Shouldn't it be tyres?

......Because the 'Aircraft Flight Manual' (American) will say 'tires'

 

[dot]

Why do people keep writing 'tires' ? Shouldn't it be tyres?

In the LOTFAP, Tires are the black rubber things on wheels - in the rest of the world, they are Tyres - as the news came from the US and US news sources, that's how they spell it and the locals don't bother to correct the spelling (Fairfax, AAP, News Corp etc) - it's much easier to cut and paste...