A380 YVR to LHR, BA 084 July 21st
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A380 YVR to LHR, BA 084 July 21st
Friend who was on the above flight sent me the text message below after arriving in UK.
Just curious what would have caused this.
Thanks in advance.
Text message:
We had an "incident" after take off where they dropped the undercarriage of the A380 back down after 10 mins or so, at a decent altitude + speed "to cool down the brakes" which were still hot ?? Couple mins like that where the drag shook whole plane and then we continued.
Just curious what would have caused this.
Thanks in advance.
Text message:
We had an "incident" after take off where they dropped the undercarriage of the A380 back down after 10 mins or so, at a decent altitude + speed "to cool down the brakes" which were still hot ?? Couple mins like that where the drag shook whole plane and then we continued.
Not a 'Bus person myself but it sounds like what PM said which is was quite simply hot brakes.
If you have somehow ended up with hot brakes on taxi out ( e.g. residual heat in brakes from previous landing due to short turnround, then long taxi out, perhaps with a few brake applications, perhaps a hot day, and maybe on a bad day a slightly "dragging" brake) and it's not impossible to get a "Brake Temp" warning or similar after take-off...the solution to which is usually laid down in the appropriate checklist which normally says something like lower the gear again for X minutes.
Worth bearing in mind the brakes can still be absorbing energy and heating up for some time after the final application on taxi out, so it's perfectly possible have no warning on takeoff but for it to appear shortly thereafter in the climb.
If you have somehow ended up with hot brakes on taxi out ( e.g. residual heat in brakes from previous landing due to short turnround, then long taxi out, perhaps with a few brake applications, perhaps a hot day, and maybe on a bad day a slightly "dragging" brake) and it's not impossible to get a "Brake Temp" warning or similar after take-off...the solution to which is usually laid down in the appropriate checklist which normally says something like lower the gear again for X minutes.
Worth bearing in mind the brakes can still be absorbing energy and heating up for some time after the final application on taxi out, so it's perfectly possible have no warning on takeoff but for it to appear shortly thereafter in the climb.
Last edited by wiggy; 24th Jul 2017 at 13:57.
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Even whilst taxiing, the brakes can heat up. On the takeoff roll, some residual brake drag exists and given a "short" turnaround, hot ambient conditions, long taxi in and out you can take off with with hot brakes, which can take time to register on the sensors. On my small aicraft the maximum brake temperatures are recorded up to ten minutes after the event. Once retracted, the airflow around the uppermost wheels is negligible. So given a delay in indications and hot brakes this makes sense.
Last edited by Piltdown Man; 25th Jul 2017 at 09:35. Reason: Spellung agin
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Do A380's have brake fans fitted like their smaller A320 cousins have as an option and if so, are they used in a similar manner?
While A320 turnarounds are often 30-45 minutes, on the A380 I would imagine that most turnarounds are in excess of 2 hours. I would have thought that was long enough to dissipate most of the heat from the landing/taxi in, while accepting that the taxi out alone will generate some heating.
While A320 turnarounds are often 30-45 minutes, on the A380 I would imagine that most turnarounds are in excess of 2 hours. I would have thought that was long enough to dissipate most of the heat from the landing/taxi in, while accepting that the taxi out alone will generate some heating.
A long taxi out, e.g. Antalya, Barcelona, can easily heat up the brakes.
Add a low passenger load and all engines running, and you will need to apply the brakes a lot, otherwise the plane just runs away. If brake fans are not fitted, this will also contribute to higher temperatures.
On Airbus A320/330, brake temperatures of 300 or more trigger a caution and 'wait for brakes to cool before take-off' message. As has been said, the brake packs retain heat for a long time, so a brake temp caution after take-off is not unheard of - you don't want 300 degree heat radiating in the wheel wells.
Does the A380 ever taxi on two or three engines?
Add a low passenger load and all engines running, and you will need to apply the brakes a lot, otherwise the plane just runs away. If brake fans are not fitted, this will also contribute to higher temperatures.
On Airbus A320/330, brake temperatures of 300 or more trigger a caution and 'wait for brakes to cool before take-off' message. As has been said, the brake packs retain heat for a long time, so a brake temp caution after take-off is not unheard of - you don't want 300 degree heat radiating in the wheel wells.
Does the A380 ever taxi on two or three engines?
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Vancouver has quite a lot of short taxiways that feed into other short taxiways with numerous sharp(er) turns. From where the heavies park in YVR, there ends up being a lot of brake use, especially if the 26's are active, and especially so if they have to taxi for 26L.
Right now, there is some construction work at the threshold of 26L that normally results in "stop-and-go" traffic on the taxiway, before taxiing a slalom course to the runway. I loathe using the brakes when I don't have to, but in and around that part of Vancouver right now, you have to.
Also, as Piltdown Man mentioned, brakes reach their maximum temperature sometime after they have been used, with 10 to 20 minutes being an average figure for the types I've flown.
So departing YVR off of 26L with any stop-and-go behind other traffic, into the slalom and then maybe holding in position for another heavy in front, and yeah this makes a lot of sense. Certainly not an incident as that is what the BA crew would have been trying to prevent!
Right now, there is some construction work at the threshold of 26L that normally results in "stop-and-go" traffic on the taxiway, before taxiing a slalom course to the runway. I loathe using the brakes when I don't have to, but in and around that part of Vancouver right now, you have to.
Also, as Piltdown Man mentioned, brakes reach their maximum temperature sometime after they have been used, with 10 to 20 minutes being an average figure for the types I've flown.
So departing YVR off of 26L with any stop-and-go behind other traffic, into the slalom and then maybe holding in position for another heavy in front, and yeah this makes a lot of sense. Certainly not an incident as that is what the BA crew would have been trying to prevent!
