Costly ground bump for Qatar at Doha Airport

Comhrá

INCIDENT: Strong wind at Doha Airport pushed a parked Boeing 787 into an Airbus A350

During a storm, a Qatar Airways Boeing 787-8 has been pushed into an Airbus A350 at Doha Airport.

https://www.airlive.net/incident-strong-wind-at-doha-airport-pushed-a-parked-boeing-787-into-an-airbus-a350/?fbclid=IwAR0bUOVVmYgntfLRT2i0ufL5Xdy4K7_rcylBGS5gi-XTKK_TOjwVFv2kcPs

Inquitus

Oooops!

StupidLikeAFox

Probably left the handbrake off. Always a good idea to stick it in gear as well as an extra failsafe.

kona

They might get away fairly handy with that.

Growler!!!

StupidLikeAFox wrote: »

Probably left the handbrake off. Always a good idea to stick it in gear as well as an extra failsafe.

Your right! When the aircraft are parked up for long periods the parking brake is normally released. When the parking brake is on, it is powered by the Hot Battery Bus and will discharge the battery over time!

kona

Growler!!! wrote: »

Your right! When the aircraft are parked up for long periods the parking brake is normally released. When the parking brake is on, it is powered by the Hot Battery Bus and will discharge the battery over time!

787 requires power to release the brakes? No power and the brake will remain engaged?

billy few mates

I've seen aircraft turned 90° like that even with the brakes fully applied, normally when you get a weather warning of high winds you try and park them nose into the wind with chocks and ballast on board to try and prevent them 'weather vaneing like this.

Aircraft brakes aren't as effective as some people might think (why do you think they use thrust reversers?) Most of them use a hydraulic accumulator to maintain hydraulic brake pressure but these can leak or deplete over time (which is why they also use chocs) when parking).
Even they won't always prevent something like this, and it's sometimes necessary to shackle the aircraft to the ground, for example during high powered engine runs.
I've personally been onboard an aircraft that jumped the chocs during a max power assurance run and despite two people fully standing on the brake pedals we slid a good fifty yards across the (thankfully empty) ramp.
Don't forget the brand new A340 that was destroyed at Airbus a few years ago when several people were seriously injured, the brakes weren't enough to save them.
Modern aircraft with their massive engines are by design multiple times more powerful than the tiny little brakes they have which basically only 'assist them' stopping.

http://avherald.com/h?article=41176dfa

Chris_5339762

...and not to mention that if they installed brakes singly powerful enough to stop the plane on a runway they'd basically go on fire every time.

lintdrummer

billy few mates wrote: »

Aircraft brakes aren't as effective as some people might think (why do you think they use thrust reversers?)

To expand on that point; Brakes are far more effective than reverse thrust in good conditions. For the A320 the increase in landing distance required by not using reverse thrust on a dry runway is negligible, 100 metres max. The standard landing calculations for a dry runway don't even consider reverse thrust.

They become more valuable on a wet or contaminated runway. Not using reverse in those conditions could add as much as 500 metres to the landing distance required. This is because with good ground friction the brakes are so good that the reversers are almost superfluous. With poorer ground friction, their effect is more pronounced as they take up the slack of the less efficient brakes.

lintdrummer

Chris_5339762 wrote: »

...and not to mention that if they installed brakes singly powerful enough to stop the plane on a runway they'd basically go on fire every time.

Nonsense, see my post above. Brakes alone will stop an aircraft on most runways with no bother at all. Many airports discourage the use of reversers, unless in case of emergency, as they are a noise pollutant.

billy few mates

lintdrummer wrote: »

Nonsense, see my post above. Brakes alone will stop an aircraft on most runways with no bother at all. Many airports discourage the use of reversers, unless in case of emergency, as they are a noise pollutant.

"Most runways..."

lintdrummer

billy few mates wrote: »

"Most runways..."

Okay then, I'll change that to "the overwhelming majority of runways". Again this applies to good weather conditions. I have yet to do a landing where runway state required full reverse to stop safely. It's not that it never happens, it's just relatively uncommon. That's not to say I haven't used full reverse on a wet day, that's just good practice, but the performance wouldn't have required it.
I have also used full reverse on very short runways which were dry. I've done many landings where I had to apply little to no braking to make an exit. On some occasions I've had to apply forward thrust on the runway, having not used the brakes nor more than idle reverse, to get to an exit more expeditiously.

You seem to disagree with what I'm saying, but I promise you I'm not making it up.

smurfjed

FAR 25-125 which is the design criteria,

(4) The landing must be made without excessive vertical acceleration, tendency to bounce, nose over, ground loop, porpoise, or water loop.
(5) The landings may not require exceptional piloting skill or alertness.
(c) For landplanes and amphibians, the landing distance on land must be determined on a level, smooth, dry, hard-surfaced runway. In addition—
(1) The pressures on the wheel braking systems may not exceed those specified by the brake manufacturer;
(2) The brakes may not be used so as to cause excessive wear of brakes or tires; and
(3) Means other than wheel brakes may be used if that means—
(i) Is safe and reliable;
(ii) Is used so that consistent results can be expected in service; and
(iii) Is such that exceptional skill is not required to control the airplane.

Thrust reversers fall into the “means other than wheel brakes”, for the majority of aircraft the thrust reversers weren’t used in the certification, therefore you don’t have to use them. If they were used in certification, you would find a restriction in the MMEL for operations with a T/R inoperative, so Chris_5339762, your statement is wrong.

On non-dry runways, as the runway friction (Mu) is low, the brakes aren’t as effective, so thrust reversers are used in these calculations with the associated penalty in the MMEL.

I have yet to do a landing where runway state required full reverse to stop safely. It's not that it never happens, it's just relatively uncommon.

Unless your aircraft states that thrust reverse is required on a dry runway, I would say that it’s ALL RUNWAYS (DRY)

The following video shows the B777 VMBE testing, the brakes/tires were expected to go on fire but remember that this is an aircraft at maximum takeoff weight rejecting from a high V1 rather than at landing weights and speeds with a full runway ahead of it.

https://youtu.be/L-by8dZrSJs