reply to post by Pilgrum
No, I wasn't going to let your point about 'rotation' get lost, I jsut forgot.
This is how we fly modern jets: We are now lined up on the runway, and have been cleared for take-off (I know, sounds silly, but that IS the
The PF (Pilot Flying) advances the throttles...we wait a bit to make sure all engines are 'spooling up' together, then we click on the Auto Throttle
button, and our hand stays on the Thrust Levers as we allow the auto system to take over and bring the thrust up to the level calculated by the
computers...at all times we have control!!
At my airline, the PF calls 'check power'. The NPF responds, 'set, X percentN1' (he announces the N1 value). The Non-Pilot Flying announces
'100 knots'. (The engines MUST be stabilized at this point, or the take-off will be rejected. Also, this verifies that BOTH airspeed indicators
are functioning, and in agreement).
Up to the call of "V1", the take-off can be aborted for any reason, at the discretion of the Captain. (because, regardless of the PF, the Captain
has control of the throttles after the initial power is set, early in the take-off).
AFTER the 'V1' call, the take-off is committed. 'V1' is the 'decision speed', predicated on temp, altitude, runway length, and gross weight of
the airplane. It is called, sometimes, a 'balanced field length' number, but that's old. Simply put, below that speed, there is sufficient runway
ahead to make a successful stop in a rejected take-off. After that speed, you are committed, and even IF an engine fails, you are guaranteed
aircraft performance and obstacle requirements are such that a successful take-off will be accomplished. This is engineered, and based on computer
models. AND, there is usually a margin of error built in...
Back to the take-off...there is the 'V1' call, and the next speed, already calculated back at the gate even before we taxiied out, as all of these
numbers are, the Vr, or 'rotate' speed. This is called by the NPF. This is when the PF begins back pressure on the controls to raise the nose at
about 2 to 3 degrees per second...and the initial pitch attitude in this is about 15 degrees, nose up. Depending on the airplane, this has to be a
fairly precise maneuver, since too rapid rotation would result in a 'tail strike'...and that is bad. Damages the airplane, naturally...and damages
the reputation of the crew...and requires a return to the airport of departure, if the damage is severe enough to prevent pressurization, which is
usually the case. (If the aft pressure bulkhead has been compromised...)
Adding...next is, announced by the NPF, 'positive rate' (he is looking at the IVSI, aka the Instant Vertical Speed Indicator) and the PF calls
'Gear Up'. The NPF then accomplishes the command, that is, he retracts the landing gear, using the landing gear lever...it's on the instrument
Very shortly after this, the Tower tells the guys to 'contact departure', and this frequency has been pre-tuned already, since we got that in our
pre-departure clearance info at the gate...so we flip the button to the new frequency, and say...XXX, XXX123 Heavy, out of a thousand, climbing to
4000...or whatever the initial altitude limits in the initial clearance were.
We verify, on initial contact, every time we change frequencies, what our altitude is. This tells the contoller that what he sees on his 'scope
confirms the altitude we are really at. Make sense?
[edit on 7-2-2008 by weedwhacker]