Airspeed active. Why say that?

[Lump Jockey]

What's the point in saying "airspeed active"? Isn't it obvious that the plane's rolling, or is it said after a certain speed?
And why say "positive rate of climb"? Is there any other form of climbing?
(Serious questions here, so no silly billies!):rolleyes:

[5150]

'Airspeed Active': confirms instrument works and cross-checks with f/o.

'Positive Climb': a very good indication that the wheels have left the ground....normally followed by 'gear up'.

[Lump Jockey]

Ok, I'll give you the Airspeed active one, it makes sense, and I suppose the other one's sensible in its own right, yet it seems like it's still kinda obvious that a 747 is airbourne. No cinisism there, really!:)

[skyrabbit]

so you know that the pitot covers were removed pre-flight??

[redsnail]

It confirms that you haven't left the pitot cover on. If you have, you won't get any airspeed info.
The positive rate call is very important at night to counter the somatogravic illusion and to ensure that you are going in the right direction (ie up) before retracting the wheels.

Oops. My spelling error has been pointed out. Sorry. :)

[Lump Jockey]

Somatic gravic illusion eh! well, well, well!:cool: Thanks for that, makes sense know I think about it! Cheers for all who bothered to enlighten me, once again!;)

[redsnail]

Perhaps I should expand. The call would confirm that "all's well" and the handling pilot is scanning correctly.
:D

[Speedbird252]

What is it then that makes it so obvious that you have positive climb? The aircraft attitude?

Just because you cant see over the dash doesnt mean that you have sufficient climb rate, or any climb rate at all.

I think.



:cool:

[Notso Fantastic]

It's not recommended to raise the undercarriage until you have a 'positive rate of climb'! The call is to trigger that.

[Intruder]

LJ:

In the 747, the nosegear lifts off several seconds before the aircraft gets fully airborne. The main gear has to extend and then lift off, the tilt mechanism has to operate correctly and actuate the interlocks (which can be heard in the cockpit), and the V/S indicators and altimeters have to agree. ONLY THEN is there a "positive climb," and may the landing gear handle be raised.

[mustafagander]

Lumpy,

Chill out a bit.

Calls to confirm airspeed alive are to ensure that the ASI is, in fact working. Not too long ago an a/c (in Central America, I think) got airbourne and flew for a while with all ASIs inop. Nasty, fatal crash. Good idea to ensure they're working, yes?

Positive rate of climb calls confirm that the weight is off the wheels, the a/c has enough attitude to start climbing away and it is safe to retract the gear.

If you have any sort of instrument rating you ought to have had it kicked into you to confirm climb and stay on the dials at least for the initial climb due somatographic illusion. In short, your inner ear cannot tell if you are accelerating or tilting your head. The little thingos in your middle ear are called "otoliths" I think. Roughly, they are hairs with a little weight on the end so that they will move under the conditions mentioned, acceleration OR attitude, and the sensation is the same.

How it kills you is so frighteningly simple - you rotate off the runway, especially one aiming out over the sea or other very dark place and not look carefully at attitude and your inner ear senses increasing pitch up as you accelerate (it's what you are expecting, so that's how your brain interprets it), so you push forward to limit attitude and not overrotate. This gives more acceleration, hence push more etc, etc, and you hit the ground/water at high speed. Your inner ear has just killed you.

[Human Factor]

On the big jets, you generally take the 'positive climb' call from the radio altimeter (radalt). The 737 in particular used to initially show a descent rate on the VSI due to the aircraft rotation rate.

On the 'bus, if the weight on wheels switch stuck or you were too quick to select the gear up, you couldn't move them.

[Lump Jockey]

First off, I AM chilled out, MUSTAFAGANDER!;) Secondly, thanks for all those who replied and taught me something new! Appreciated!:) A lot of it was common sense in the end, but also sound. Cheers!
Lumpy!

[411A]

Would suggest that using the radio altimeter for confirming positive climb after takeoff in large jet transport aircraft is really not a good idea...uneven sloping (downhill) terrain being the obvious reason.

The only really reliable instrument for confirming positive climb is the PRESSURE altimeter, and is so stated in many airline operating manuals.

[OzExpat]

I use the airspeed call, in the first instance, to confirm normal acceleration. Mostly, I have a pretty good idea of how far along the runway that I should hear that call. Thus, if I don't hear it by then, I take a quick glance to see if my ASI is registering anything at all.

This has been very useful to me, throughout my career, on critically short runways.

I take "positive rate" from the IVSI. I had one time when PNF made the call while the rate was negative. :eek: I did a momentary double-take on that one! :D

[scanscanscan]

If you want to know how to fly a large aircraft safely and stay outa trouble you can do no better than ask and listen to 411A.
You may not like his manor of delivery but possibly that is his technique to ensure you remember what he says.
We should be thankful he has takes the time in his retirement to caution and warn and pass on his considerable lineflying experiance to us, and this information is FREE.
IMHO...Possibly a better call than "Airspeed active" is the Boeing call of "80kts" and the response of "Cross checked"
What these calls require to be observed is often forgotten or unkown. Indeed they have not always been taught and are assumed by instructors faced with the quick conversion course time limitations as "Common knowledge."
Some of the things the "80 kts" call ment to me were.... My left and right airspeed indicators agree and importantly the standby emergency airspeed indicator also agrees.
Thanks to Mr Boeing this scan was a nice all in line near horizontal scan.
The "Positive climb" call... It is observed that the Ivi and the pressure altimeter and the standby emergency altimeter and the radio altimeter of the pilot required to make this call All show a positive climb.
When the other pilot also observes ALL the above indications on his instruments he answers "Confirmed"
Then the request "Gear up" is made and it is activated in a controlled slow and unrushed manner.
I feel it is very important for pilots to include the standby instruments in their instrument flying scan on takeoff and after rotate and during initial climb and also at other critical times.
Sadly since the Comet days there have been fatal accidents due the handling pilot being seduced to follow a single failing pitch attitude indicator when there was also two other easily checkable sources of this information in front of him.
A situation where a simple two outa three check could have kept them alive.
This cross scan could have alerted him that something was very wrong early enough for him to fly power airspeed altimeter safely enough and not lose control until the rouge instrument was identified and selected out of the system.
This Handling pilot safety scanning is needed especially if the non handling pilot is also failing on this particular night for whatever reason to also scan correctly as a safety back up.
Especially important with a two man crew or on a three man crew where the flight engineer is not fully intergrated in the flight instrument scanning and flight progress.
Interestingly the flight engineer of a 747 which crashed climbing off RW27 Bombay over the ocean one black night was recorded asking the Captain to "Fly by this" as attitude control was lost.
Fly by this.... was believed to have ment... The standby emergency attitude instrument. I do not remember any Fo input on the CVR tape.
I believe this 747 entered the water with a rate of descent of 10,000 feet per minute plus with a bank angle of over 110 degreees.
Also a 747 out of Stanstead was afflicted with an ADI problem. Crew monitoring back here up also failed to prevent a crash.
So for 2003 boys as handling pilot,please do not forget to scan yours and scan the standby, and if they disagree scan his.....
Fly safe... scanscanscan:):) :)

[Human Factor]

411A,

I think you'll find if the radalt is decreasing immediately after takeoff then there are slightly more pressing concerns. All you are trying to achieve at this stage is ensuring that you are clear of the deck before you raise the gear.:rolleyes:

[5150]

Indeed - our SOP's replace an 'Airspeed active' with an '80 knots' call instead.

Called by the PNF, it also doubles up as a 'dead-man's' check on the PF - if there is no response of 'check' by the PF at 80 knots, the PNF assumes the PF has dropped dead and assumes control.......in theory anyway!

[Lump Jockey]

It appears to me, you are ALL very clever people doing a great job.:)

[purr]

I rejected once at 80 knots .IAS disagree ,water in the pitot.The 80 Knots call worked fine .:cool: