Thanks for the replies. No, it wasn’t at YYZ.
And the correct answer (
What did I do?) is............. (drum roll)............
I stopped.
Why?
Because I was scared that we were going off the side of the runway at high speed and I figured that if that happened, I would rather be slowing down already instead of blasting along at full power.
I wasn’t sure that we could get airborne before we left the paved surface, partly because the ASI was unreadable with all the vibration. Also, although I felt that the swing and vibration was caused by a tyre problem, I was not certain that some other damage to the flight controls, engines or structure had occurred.
The 'bottom line' was that the aircraft was in effect 'out of control' and I wanted to get it back under control. The simplest way seemed to be to close the thrust levers and hit the brakes. The decision was influenced by the fact that my last memory of the ASI was that it was below V1 and that there seemed to be quite a lot of runway remaining.
We closed the thrust levers, applied brakes (deployed the speedbrakes as well) and were worried to find that the RH brake pedal was 'floppy' and had no effect. The LH pedal seemed to be working but that gave us a yaw, which, although in a beneficial sense to start with, was going to give us problems eventually......so we took our feet off the brakes and used the manual emergency brake handle.
As this was happening, the vibration stopped and the aircraft adopted a right-wing-low attitude. The rudder was effective in helping us regain and maintain the centreline until the speed reduced.
We slid to a stop on the centreline with about 2,000ft of runway remaining. Everything from that point on (shutdown, ATC comms, Fire Services, etc) was as ‘routine’ as you would expect.
On inspecting the damage, the RH tyre had completely disappeared, the RH wheel rim was worn into a ‘D’ shape, the RH flap, gear door, lower wing and tailplane had impact damage from the rubber fragments and the RH brakes were leaking fluid.
There was a bright metal skid mark leading back from the RH wheel down the runway, which then changed into a black rubber skid mark.
The ‘balanced field length’ for this take-off was about 4,000ft. We had a 10,000ft runway and we elected to use the full length. OAT was about 32C and the elevation was about 1,000ft.
We used 8,000ft of runway, about double the ‘book figure’ for the conditions. I think this is explained by the following factors:
- We were very close to V1 when the problem occurred;
- We took a few seconds to recognise, control, analyse, and decide; and
- The braking effort was not 100%.
Did I make the right decision?
Thanks to those who point out that it can’t have been so bad, as I’m here to tell the tale. Based on the successful outcome and the actual damage inflicted on the aircraft (over $100,000 repair bill) I think on balance it probably was the right decision. Had I managed to get the thing airborne, I think in retrospect it would have been flyable. I would have kept the gear down and eventually would have landed back on the full length of the 10,000ft runway. Against that, the extensive damage that I saw after the event helped to convince me that keeping it on the ground was the right thing to do. I did have some doubts during the initial few minutes after we stopped: ‘Were we above V1?’ ‘In the simulator, we were trained to continue the take-off.’ ‘Could I have got airborne before going off the side?’ etc, etc.
On the other hand, if we had got airborne, we could have had jammed elevators, jammed flaps, fuel leaks, etc. The damage was serious enough that all of these ‘nasties’ were a real possibility.
To be perfectly honest, I just had a ‘bad feeling’ as we were sliding towards the side of the runway, and ‘self-preservation’ over-ruled the theoretical training which was going round my head at the time. It was almost instinctive to close the thrust levers.
What did I learn?
1. Self-preservation is a very powerful impulse; it can be difficult to resist even if your training tells you that another course of action may be appropriate.
2. Balanced field lengths assume timely and correct action in the event of an RTO. They also assume that the brakes will be working correctly.
3. The old adage, ‘one of the most useless things is runway behind you’ is true! Intersection take-offs are of course fine, but the full length is better!
4. Burst tyres can cause loss of control, severe difficulty in reading the instruments and lots of structural damage.
5. A real ‘event’ is probably going to be quite different to what you have seen in the simulator.
Hope this is of interest.
Eck