Rejecting a takeoff
As per our sop, below 80kts we are to reject for a system failure (and then a list of other abnormalities like vibration, slow acceleration etc etc)
So does that mean we reject for ANY system failure. So below 80kts if you see the master caution light come on, do you automatically stop-without identifying why the light came on or finding out the problem? What do you guys think? What sort of thoughts/mindsets do you keep when on the takeoff roll with regards to rejecting? (apart from hoping you don't have to!) |
apart from hoping you don't have to |
high-speed/low-speed RTO
Many companies prefer to comply with the Aircraft Manufacturer's recommendation concerning RTOs. The builder of the jet I fly determined that 80 knots is an important boundary during takeoff...a boundary between the lower speed RTO and the high speed RTO.
The RTO autobrakes in the jet will not engage at speeds below this 80 knot decision point, so the abort will not be as dramatic as with a high speed RTO. Above 80 knots certain events will not illuminate the Master Caution light during the takeoff roll...they don't want to highlight the event until the jet is airborne. I am on-board with this line of thinking from the manufacturer...both becuase it makes sense to me, and because our leadership says this is our SOP. I have not yet met another pilot at my company who disagrees with this SOP. Prior to 80 knots abort for: Activation of the Master Caution System Failures Unusual noise or vibration Tire Failure Abnormally slow acceleration Unsafe takeoff configuration warning Prior to V1 Engine failure Fire or fire warning Predictive Windshear Caution or Warning Above V1: If the airplane is unsafe or unable to fly |
Below 80 knots we'll consider anything for a reject. That doesn't mean we'll be rejecting for anything. Above 80 and between 80 and V1, our operator defines any rejected takeoff as a high speed rejected takeoff. In this environment, we're only going to consider stopping for an engine fire, failure, loss of directional control, outward opening door, or condition that makes the aircraft unsafe to take airborne. Beyond V1 we're going flying.
There's noting on our forward caution panel worthy of a high speed rejected takeoff (B747 Classic). |
To RTO, or not RTO, is the question...
Nothing wrong with your numbers and procedures mentioned above.
If "out-of-the-box" numbers, they apply much to the A-320/B-737 types. That 80 knots if a fine figure to consider. Operating from a typical 6 or 7,000 feet long runway. xxx Consider other (higher numbers) if larger airplanes and longer runways. No too excessive numbers, just slightly higher numbers. Certainly, RTO at 100 knots can be considered for a 737 on a 12,000 runway. xxx Personally, the earliest "GO" speed in the 747-200 was 120/130 knots. That is except engine failure or fire/fire warning cases. But for a 747, you often deal with V1 much higher than 80 knots. I mention the 120/130 knots to be above VmcG. A typical V1 for a classic 747 is some 145-160 knots. This on runways anywhere between 10 and 14,000 feet long. xxx Then think about actual conditions, dry or slippery runways. But again, I would recommend to input the VmcG in you decisions. Hope we do not get into the old "Pprune V1 discussion" again... xxx :ugh: Happy contrails |
Reject
Many new large aircraft lock out the master warning and engine fire alert at 100kts...only an actual engine failure is recommended for a rejected take-off between 100kts and V1.
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Many new large aircraft lock out the master warning and engine fire alert at 100kts...only an actual engine failure is recommended for a rejected take-off between 100kts and V1. |
But for a 747, you often deal with V1 much higher than 80 knots Many new large aircraft lock out the master warning and engine fire alert at 100kts |
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