Positive Rate, Gear Up
Discussion
Question for the pilots please. On commercial airliners during take off they hit V1, rotate and then as the plane is climbing the pilot flying says positive rate, gear up. Pilot monitoring raises the landing gear.
Why is "positive rate" important and why is it mentioned? Surely at that point they are committed to getting the plane in the air, there is likely little to no runway left, and if there is a problem then surely getting the gear up is important anyway to reduce drag? Wondering why you don't gear up the minute it leaves the ground?
Why is "positive rate" important and why is it mentioned? Surely at that point they are committed to getting the plane in the air, there is likely little to no runway left, and if there is a problem then surely getting the gear up is important anyway to reduce drag? Wondering why you don't gear up the minute it leaves the ground?
V1 is simply the speed (and, as a proxy, the point along the length of the runway) where the plane is commited to taking off if an engine fails etc.
You can have all wheels firmly on the ground at V1.
Similarly, 'rotate' only means that that is the speed at which a positive control input is made to raise the nosewheel off the tarmac and increase the angle of attack of the wings.
Usually this will fairly quickly cause the plane to leave the ground and climb. But some types (and certain conditions) take a time to actually lift off after rotation. And that can also happen if the lift-producing quality of the wings has been degraded (say, by icing or flaps at the wrong setting). There have been several crashes where planes with iced wings have ploughed off the end of the runway when they've had enough lift to rotate but not enough to lift off.
The only way the crew can be sure that the plane is actually off the ground and they don't need the undercarriage any more is an indication of the aircraft gaining altitude, not just a nose-up attitude. So they wait for an indication that the plane has left the runway, is gaining altitude and is doing so at a consistent and expected rate, before folding the landing gear away.
You can have all wheels firmly on the ground at V1.
Similarly, 'rotate' only means that that is the speed at which a positive control input is made to raise the nosewheel off the tarmac and increase the angle of attack of the wings.
Usually this will fairly quickly cause the plane to leave the ground and climb. But some types (and certain conditions) take a time to actually lift off after rotation. And that can also happen if the lift-producing quality of the wings has been degraded (say, by icing or flaps at the wrong setting). There have been several crashes where planes with iced wings have ploughed off the end of the runway when they've had enough lift to rotate but not enough to lift off.
The only way the crew can be sure that the plane is actually off the ground and they don't need the undercarriage any more is an indication of the aircraft gaining altitude, not just a nose-up attitude. So they wait for an indication that the plane has left the runway, is gaining altitude and is doing so at a consistent and expected rate, before folding the landing gear away.
On our aircraft we have 3 rate of climb indicators. The none handling pilot checks all 3 and then says. Positive on 3.
The flying pilot then calls for gear up.
None flying pilot then operates the gear up. Calls Traveling and then gear up.
The none flying pilot then calls when it’s safe to raise flaps giving the new minimum speed. Then follows it by the manoeuvre speed. Then the clean call.
All of these critical speeds are cross checked by both pilots and called as cross checked. Our Air engineer is a 3rd set of eyes but won’t call anything unless he sees an error.
The flying pilot then calls for gear up.
None flying pilot then operates the gear up. Calls Traveling and then gear up.
The none flying pilot then calls when it’s safe to raise flaps giving the new minimum speed. Then follows it by the manoeuvre speed. Then the clean call.
All of these critical speeds are cross checked by both pilots and called as cross checked. Our Air engineer is a 3rd set of eyes but won’t call anything unless he sees an error.
Edited by MB140 on Saturday 10th April 22:02
Usually there's some history to the official wording of all these things related to ensuring unambiguity.
For example, "No" and "Go", on a radio & with background noise could be easy to confuse and quite disastrous.
So the phrases are chosen carefully to ensure that during high workload, poor radio comms and high background noise, the guys'n'girls don't have to keep saying pardon, or worse, hear the wrong thing.
For example, "No" and "Go", on a radio & with background noise could be easy to confuse and quite disastrous.
So the phrases are chosen carefully to ensure that during high workload, poor radio comms and high background noise, the guys'n'girls don't have to keep saying pardon, or worse, hear the wrong thing.
eharding said:
Interesting video here of an example of a 737 getting briefly airborne, and the crew then having to put it back on the runway before finally taking off again. Worth watching to the end, as the explanation isn't quite what you'd might expect.
Thanks, that is interesting. What amazes me, as a non pilot, is the quick thinking. You pull back and nothing happens, you have seconds to decide what to do next. You know you have to get the plane airborne, but how. Amazing.Next question, un related. The A380. How the f
k does that thing fly. Its fking enormous. Arnie Cunningham said:
I avoided this chaps reaction videos because of the ridiculous faces he pulls on the cover.
But actually, I found it interesting. Just if his cover pic was a bit less ridiculous.
Does anyone follow "Curious Android" on YT? I find some of his stuff interesting too.
Mentour Pilor's YouTube splash screen gurnings always make me smile, as they're a mile away from the invariably calm, informed and methodical delivery of the actual content.But actually, I found it interesting. Just if his cover pic was a bit less ridiculous.
Does anyone follow "Curious Android" on YT? I find some of his stuff interesting too.
Curious Droid's output is also very good, despite Paul Shillito's choice of shirts threatening to burn out pixels on my TV.
Ayahuasca said:
When did co-pilot become non-flying pilot?
‘God is my non-flying pilot’ doesn’t have the same ring.
Anyway, technically, they are both flying.
Assigning the roles of pilot-flying and pilot-non-flying confers a clear set of responsibilities to both flight crew so that each knows what they should be doing at each stage of the duty and they also know what the other should be doing. For example in pre flight, the PF could conduct internal checks whilst the PNF does the external walk around, during the flight the PNF operates the radio, etc. Each company will have their own operating procedures that define who does what.‘God is my non-flying pilot’ doesn’t have the same ring.
Anyway, technically, they are both flying.
This ^^
In some of the famous crashes, it's actually been the co-pilot/first officer who's been hands on. When the st's going down, you don't want to be fannying about changing roles midway through and end up confusing things.
On BA Flight 38, IIRC it was the first officer who was hands on bringing the plane in.
Do I remember that the Captain, Peter Burkill was also a glider pilot? And he went off book to retract the flaps, reducing drag just enough to get the aeroplane over the fence and prevented a substantially worse crash?
In some of the famous crashes, it's actually been the co-pilot/first officer who's been hands on. When the s
t's going down, you don't want to be fannying about changing roles midway through and end up confusing things.On BA Flight 38, IIRC it was the first officer who was hands on bringing the plane in.
Do I remember that the Captain, Peter Burkill was also a glider pilot? And he went off book to retract the flaps, reducing drag just enough to get the aeroplane over the fence and prevented a substantially worse crash?
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