What is the difference between V! and V2, can you stop after V2?

Question

What is the cockpit conversation between the 1st officer and the PIC during takeoff? Usually it is a newer Pilot who does the take off, what if he gets it wrong (lets look at Comair's recent crash) when do you stop the TO run, what is the next step? I would love to hear some " real stories" of this problem. I DO NOT blame any member of the Flight Crew for the accident in KY. I am sure the flight crew did there best, and I am sorry for the loss of life of the crew and passengers.

Answer 1

To add to the pertinent answers already provided, it is important to remember that V1 applies to take off with an engine failing at the worst moment. If the engine fails and is recognized as such by the crew before V1 is called, then it is safer to stop as it would require less runway. If an engine fails after V1 is reached, then accelerating on the remaining engine(s) and get airborne will take less room than stopping.

Now, there may be instances where the take-off is aborted for reasons other than the loss of an engine, and it is up to the crew to ake a judgment call on that (yes, in the heat of the moment, those people are paid and got the job as pilots because they showed they can make good decisions quickly -- which does not mean they are always right, unfortunately).

In the case of the KY crash, the airplane did not lose engine power, and because of that, its takeoff distance would have been much less than the one with one engine failing just at V1. Unfortunately, it turned out that the two engine takeoff distance was just a bit longer than the length of the runway.

V1 is restricted to be less than Vr (rotation speed). If a plane lose power on one engine at Vr, then it is committed to take off. V2 is the speed that the airplane can climb best with one engine inoperative, that is the speed that should be maintained in case, again, of an engine failure at that point in time. At V2 you are airborne.


The attached link is perhaps one of the best I have seen on the web about this.

Answer 2

It is the pilot flying that does the takeoff, usually the captain. The copilot calls the speeds.

The captain's hands are on the throttles until V1, if an abort is called, he will pull them back, activate the spoilers/speedbrakes, and apply maximum brake or the autobrake to RTO (rejected takeoff which is the highest setting). Thrust reversers/prop reverse isn't used due to the possibility of assymetric thrust from an engine failure.

After V1, the captain takes his hand off the throttle and the copilot puts his hand on them and the aircraft is commited to flying.

V1 is based on aircraft weight, density altitude, and available runway. Within the runway distance, the aircraft should be able to accelerate to V1 and abort. This is called a 'balanced field'. The takeoff thrust is adjusted to maintain a balanced field for different runway lengths.

That's the theory, in reality it's much different.

I remember a few years ago, a Canadian Airlines DC-10-30 was taking off form Vancouver International and it wound up overshooting the runway after an abort. The takeoff was a rolling takeoff and takeoff thrust wasn't set until several thousand feet down the runway. Then an engine failed after V1. The captain thought it was a bomb, waited a few more seconds, and then aborted. Whoops!

Here is the report: Capain aborted TWO SECONDS after V1

http://www.tsb.gc.ca/en/reports/air/1995/a95h0015/a95h0015.asp

Answer 3

V1 is the take off decision speed whereby if the take off is continued after an engine failure, it will be possible to continue the take off safely. It is also the speed whereby, if the Captain abandoned the take off, it will be possible to bring the aircraft to a safe stop within the remaining Runway.

VR is the rotation speed where the Captain begins to rotate the aircraft to lift off attitude and climb away safely.

V2 is the Take Off Safety and Initial Climb Speed to achieve a certain height at a certain distance.


So answering your question, once you hit Vr, you have pulled your yoke back and taken off.

Very little conversation.... fresh pilots do a lot of TO/Landings... it is the job of the captain to supervise.

My friend is a commercial pilot and I am a student pilot and I have sat in the observer chair many times during flight training in a 727.

Answer 4

V1 is the state in the takeoff roll that the pilot checks all gauges and switches and that to make sure they are in the correct position or that they work properly, after V1, which is calculated based on wind speed, aircraft load and a whole bunch of other factors, the plane will not have enough runway left to slow down on... all in all, no it is not possible to stop after V1 has passed...

Answer 5

Best so far is Vincent G.

During the take off run, a pilot will abort the take-off for any (abnormal) reason below 80 to 100 kts (depending on aircraft), above 80-100, but below V1, the pilot will abort only for engine failure, fire or aircraft configuration (flaps rise from t-o position). above V1 the take-off is continued.

Vr is always = or > than V1.

Most airlines have the pilots sharing the flying load, both the pilot and co-pilot can, and are trained to take-off even with an engine failure at V1.

Answer 6

The simplest answer is this.

Before V1 - Always stop
After V2 - Always go

The gray area comes between V1 and V2 where the aircraft is capable of stopping or flying, and depending on where you are in that range, one or the other may be the better choice. Many aircrews brief their takeoff procedure so that there is no doubt of what they will do between V1 and V2.

Answer 7

No, you cannot stop after V- rotate), V1 is before V-rotate. It is usually the PIC who does the take off and the communciations between them confirms the procedure being undertaken.

Answer 8

I thought you were talking about the German V1 and V2 rockets.