"Positive rate" callout
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"Positive rate" callout
Did a quick search on the forums, but couldn't find anything on this topic:
My question is: Does your company use the "positive rate" callout to trigger gear retraction after take-off or go-around? Mine does - but I feel that it is an error-prone trigger, especially in an emergency: If the PNF forgets the "pos. rate" callout, which could happen in a stressful situation; it's much easier for the PF to forget the "gear up" call. Seen this happen in the SIM a few times.
Thoughts/comments? Any published research on this subject (callouts in general) out there?
Might not be the biggest issue in the world of aviation, but I'm a fan of 'attention to detail'...
My question is: Does your company use the "positive rate" callout to trigger gear retraction after take-off or go-around? Mine does - but I feel that it is an error-prone trigger, especially in an emergency: If the PNF forgets the "pos. rate" callout, which could happen in a stressful situation; it's much easier for the PF to forget the "gear up" call. Seen this happen in the SIM a few times.
Thoughts/comments? Any published research on this subject (callouts in general) out there?
Might not be the biggest issue in the world of aviation, but I'm a fan of 'attention to detail'...
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HI, Crossunder: "Positive Rate" - Yes we use it - though some have their own variation "Positive Climb" from their own prior backgrounds, despite what it says in our manuals.
Yes, also seen it go wrong in the sim under pressure when the call "Positive Rate" perhaps gets forgotten.
On the whole, a prime purpose of callouts could be said to be focussing the attention of the caller on what exactly must be watched, so that the call can be made. The rate of climb and some evidence of being higher must be monitored closely before raising the gear.
You are quite right to point out that this call can degenerate unintentionally into a prompt by Pilot Monitoring (PM) for the Pilot Flying (PF) to call for "Gear Up". As you say, "an error-prone trigger, especially in an emergency". Without the prompt, you as PF might discover under stress that you had trained yourself not to bother thinking to call for the gear, just to react to the prompt and respond with a call for the gear. Thence the situation you and I have seen in the sim, of 2 intelligent pilots a minute later amazed that even at full thrust on the one engine, it still will barely climb, not even noticing the three accusingly green lights.
One remembers when we introduced the "silent cockpit" principle during engine starts. There was no more need for PF to make sequential calls like "N1, ignition, fuel flow, EGT, stabilised ". Apparently these calls might distract other crew member(s) who might miss something they would otherwise have seen - good sense. After a while it became obvious that the critical focus on those parameters was now lacking, and they were often not being monitored well or at all, simply because the parameter callout was not required any more.
We found a good answer was to train yourself well, probably by making the parameter calls in your head to yourself at each stage of the start as PF, just not verbalising them so as not to distract the PM(s). That gave us the best of both worlds - the critical focus, and the 2-crew (or 3-crew) undistracted principle of the silent cockpit.
This can work well in the "Positive Rate" trap you describe: you must train yourself as PF to ask yourself "Going UP yet ?" every time you pull back to raise the nose to the climbing attitude. Train yourself that when you have answered "yes" to yourself, you will say "Gear Up". Make sure there is no requirement in your airline for the PM to make the "Positive Rate" call BEFORE you as PF call for "Gear Up" - when you as PF see rate and height gain, call for the Gear. Meanwhile the PM will have been focussed on height and rate waiting to make the "Positive Rate" call, will soon complain if there is danger, won't raise the gear if there is, will raise it if all is well. Your "gear Up" call will have broken any pressure-induced trance PM might momentarily have been in, befuddled by pressure.
On the whole, I vote for the "Positive Rate" callout, because of its value as a focus tool, recognising the danger of it becoming a prompt, and I use it as described above with my silent additions. The lack of a callout requirement would probably mean my failure as PM to focus on an essential, especially under pressure, which would be worse.
Now - did I re-engage LNAV after that radar heading ? Perhaps a call-out would help ?
Yes, also seen it go wrong in the sim under pressure when the call "Positive Rate" perhaps gets forgotten.
On the whole, a prime purpose of callouts could be said to be focussing the attention of the caller on what exactly must be watched, so that the call can be made. The rate of climb and some evidence of being higher must be monitored closely before raising the gear.
You are quite right to point out that this call can degenerate unintentionally into a prompt by Pilot Monitoring (PM) for the Pilot Flying (PF) to call for "Gear Up". As you say, "an error-prone trigger, especially in an emergency". Without the prompt, you as PF might discover under stress that you had trained yourself not to bother thinking to call for the gear, just to react to the prompt and respond with a call for the gear. Thence the situation you and I have seen in the sim, of 2 intelligent pilots a minute later amazed that even at full thrust on the one engine, it still will barely climb, not even noticing the three accusingly green lights.
One remembers when we introduced the "silent cockpit" principle during engine starts. There was no more need for PF to make sequential calls like "N1, ignition, fuel flow, EGT, stabilised ". Apparently these calls might distract other crew member(s) who might miss something they would otherwise have seen - good sense. After a while it became obvious that the critical focus on those parameters was now lacking, and they were often not being monitored well or at all, simply because the parameter callout was not required any more.
We found a good answer was to train yourself well, probably by making the parameter calls in your head to yourself at each stage of the start as PF, just not verbalising them so as not to distract the PM(s). That gave us the best of both worlds - the critical focus, and the 2-crew (or 3-crew) undistracted principle of the silent cockpit.
This can work well in the "Positive Rate" trap you describe: you must train yourself as PF to ask yourself "Going UP yet ?" every time you pull back to raise the nose to the climbing attitude. Train yourself that when you have answered "yes" to yourself, you will say "Gear Up". Make sure there is no requirement in your airline for the PM to make the "Positive Rate" call BEFORE you as PF call for "Gear Up" - when you as PF see rate and height gain, call for the Gear. Meanwhile the PM will have been focussed on height and rate waiting to make the "Positive Rate" call, will soon complain if there is danger, won't raise the gear if there is, will raise it if all is well. Your "gear Up" call will have broken any pressure-induced trance PM might momentarily have been in, befuddled by pressure.
On the whole, I vote for the "Positive Rate" callout, because of its value as a focus tool, recognising the danger of it becoming a prompt, and I use it as described above with my silent additions. The lack of a callout requirement would probably mean my failure as PM to focus on an essential, especially under pressure, which would be worse.
Now - did I re-engage LNAV after that radar heading ? Perhaps a call-out would help ?
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Very very good comments by 2LP.
It all comes down to (CRM) technique and not procedures. I too felt once very embaressed in the sim for one full minute figuring out why we were not climbing at a proper rate......
Before I switched to airline flying I was in a company which barely had SOP's. Due to the nature of the business it was no use really having them as every operation required different procedures depending on operational circumstances. So before start up there was some thinking to do how to handle a certain task. This made the whole crew very aware of the whole situation the airplane was in, from beginning till the end.
When I became a line pilot, in the beginning I was very relieved the whole operation was so "easy". Just start at step 1 and than do step 2 etc...... Till I realised bij incidents as above that I (and not only me) completely forgot the whole issue of flying (what situation am I in, and what situation am I gonna be next?). So I switched back to my "former" mind state of thinking about the "big picture" instead of the next step in the "call out" sequence. Especially when things are getting busy or not going as planned you're much more in control of the whole situation and "attention to detail" is always there in the right amount with the proper timing.
Unfortunately as I see it, most companies (and flying schools) train on procedures and not (CRM) techniques.
It all comes down to (CRM) technique and not procedures. I too felt once very embaressed in the sim for one full minute figuring out why we were not climbing at a proper rate......
Before I switched to airline flying I was in a company which barely had SOP's. Due to the nature of the business it was no use really having them as every operation required different procedures depending on operational circumstances. So before start up there was some thinking to do how to handle a certain task. This made the whole crew very aware of the whole situation the airplane was in, from beginning till the end.
When I became a line pilot, in the beginning I was very relieved the whole operation was so "easy". Just start at step 1 and than do step 2 etc...... Till I realised bij incidents as above that I (and not only me) completely forgot the whole issue of flying (what situation am I in, and what situation am I gonna be next?). So I switched back to my "former" mind state of thinking about the "big picture" instead of the next step in the "call out" sequence. Especially when things are getting busy or not going as planned you're much more in control of the whole situation and "attention to detail" is always there in the right amount with the proper timing.
Unfortunately as I see it, most companies (and flying schools) train on procedures and not (CRM) techniques.
Good inputs from 2LP and hac.
My concern is that this historical call is now misused or misrepresented in modern aircraft. In olden days as aircraft were cleared for take off in lower visibilities there was increasing need to use instruments to check that a climb had been established before retracting the gear. At first the altimeter was used due to lags in the old steam driven VSIs. With the advent of IVSI then this instrument was used. In modern aircraft, the VSI may have greater inertial input or even be totally inertial; the result of the improved display is that the positive rate is established more accurately, but also more quickly with the danger of rushed calls and procedures.
Nowadays the crew have lost the big picture: for most take-offs the positive rate can still be established from external visual cues. The instrument check is a good and necessary monitor for the difficulties in larger aircraft or the avoidance visual illusions, but it tends to keep the monitoring pilot head down, whereas after lift off some of the monitoring task is head up and less dependant on instruments. Using the call in a CRM way could be a trigger for the change in monitoring technique.
Also, back to basics as to why the crew require a quick gear retraction and hence a quick check that the aircraft is climbing. The situation would be following an engine failure before V2; it is critical that the positive rate call is accurate; hence use instruments, but how many monitoring pilots are aware of the range of climb rates (often very low) after an engine failure? Room for error; so teach the big picture, positive rate is VSI, and altimeter, and aircraft system, that will subsequently include gear up. No need to rush the normal operation, but the failure case has to be correct every time.
My concern is that this historical call is now misused or misrepresented in modern aircraft. In olden days as aircraft were cleared for take off in lower visibilities there was increasing need to use instruments to check that a climb had been established before retracting the gear. At first the altimeter was used due to lags in the old steam driven VSIs. With the advent of IVSI then this instrument was used. In modern aircraft, the VSI may have greater inertial input or even be totally inertial; the result of the improved display is that the positive rate is established more accurately, but also more quickly with the danger of rushed calls and procedures.
Nowadays the crew have lost the big picture: for most take-offs the positive rate can still be established from external visual cues. The instrument check is a good and necessary monitor for the difficulties in larger aircraft or the avoidance visual illusions, but it tends to keep the monitoring pilot head down, whereas after lift off some of the monitoring task is head up and less dependant on instruments. Using the call in a CRM way could be a trigger for the change in monitoring technique.
Also, back to basics as to why the crew require a quick gear retraction and hence a quick check that the aircraft is climbing. The situation would be following an engine failure before V2; it is critical that the positive rate call is accurate; hence use instruments, but how many monitoring pilots are aware of the range of climb rates (often very low) after an engine failure? Room for error; so teach the big picture, positive rate is VSI, and altimeter, and aircraft system, that will subsequently include gear up. No need to rush the normal operation, but the failure case has to be correct every time.
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I work for an airline that, in my humble opinion, has far too many redundant 'standard calls', however, in the case of this topic, again IMHO, I think that they got it right.
The basic philosophy for all cockpit actions is that the PF initiates all calls for configuration / thrust changes, and the PNF, after verifying that the call is reasonable, SILENTLY carries out the action.
The gear retraction process goes like this -
(1) The PF, after silently verifying 'ground break' visually, IVSI alive, RA increasing will call "Gear Up"
(2) The PNF, after silently carrying out the same verification, silently selects gear up. Both pilots silently monitor that the gear does indeed fully retract.
(3) If the PF has omitted to call for gear up when all indications are that it should have been, the PNF will call "Positive Climb", and again with increased emphasis if ignored.
(4) If, following item (3) the PF makes no verbal response, Pilot Incapacitation is assumed, and subsequent actions by the PNF will be in accordance with this scenario.
I didn't invent it, and I don't endorse it just because my airline uses it. I like it because it works well in line with the best thinking on the Silent Cockpit concept, good CRM, clear division of duties with all configuration changes at the PF initiative, and good Crew Incapacitation management.
P.S. Is there really a Malaysian airline where the PNF makes uncommanded gear retraction? Surely you jest!
The basic philosophy for all cockpit actions is that the PF initiates all calls for configuration / thrust changes, and the PNF, after verifying that the call is reasonable, SILENTLY carries out the action.
The gear retraction process goes like this -
(1) The PF, after silently verifying 'ground break' visually, IVSI alive, RA increasing will call "Gear Up"
(2) The PNF, after silently carrying out the same verification, silently selects gear up. Both pilots silently monitor that the gear does indeed fully retract.
(3) If the PF has omitted to call for gear up when all indications are that it should have been, the PNF will call "Positive Climb", and again with increased emphasis if ignored.
(4) If, following item (3) the PF makes no verbal response, Pilot Incapacitation is assumed, and subsequent actions by the PNF will be in accordance with this scenario.
I didn't invent it, and I don't endorse it just because my airline uses it. I like it because it works well in line with the best thinking on the Silent Cockpit concept, good CRM, clear division of duties with all configuration changes at the PF initiative, and good Crew Incapacitation management.
P.S. Is there really a Malaysian airline where the PNF makes uncommanded gear retraction? Surely you jest!
Good discussion.
I come from a "Positive Climb" company and yes, the call does get missed sometimes but the HP just ends up calling "Gear Up" at which point the NHP realises he's missed the call, checks that we're going up and repeats "Gear Up?" back to the HP and if no objection occurs, raises the gear.
I think that the most important use of the "Positive Climb" call is in a low go-around (think catIIIa or catIIIb). It's pretty vital that you don't land having raised the gear: a missed approach initiated from 15' is likely to lead to a 'touch-and-go' in most passenger aircraft during normal operation.
In the big, long thing I fly you can have the nose quite a distance into the air, some time after rotation, with the main gear still on the ground, so the visual clues are not brilliant. However, there's not normally any reason to 'rush' the gear retraction, so why be trigger happy? I instigate my call from an increasing rad alt.
[Edited to change 'rate' to 'climb'. Too much flying has addled the brain
]
I come from a "Positive Climb" company and yes, the call does get missed sometimes but the HP just ends up calling "Gear Up" at which point the NHP realises he's missed the call, checks that we're going up and repeats "Gear Up?" back to the HP and if no objection occurs, raises the gear.
I think that the most important use of the "Positive Climb" call is in a low go-around (think catIIIa or catIIIb). It's pretty vital that you don't land having raised the gear: a missed approach initiated from 15' is likely to lead to a 'touch-and-go' in most passenger aircraft during normal operation.
In the big, long thing I fly you can have the nose quite a distance into the air, some time after rotation, with the main gear still on the ground, so the visual clues are not brilliant. However, there's not normally any reason to 'rush' the gear retraction, so why be trigger happy? I instigate my call from an increasing rad alt.
[Edited to change 'rate' to 'climb'. Too much flying has addled the brain
]
Last edited by FullWings; 8th Sep 2004 at 21:31.
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There's a distinct difference between "positive rate" and "positive climb." We always use the latter according to SOP.
It's an altimeter call rather than the VSI call which in some airfames is more susceptible to erratic ground effects than the altimeter.
It's an altimeter call rather than the VSI call which in some airfames is more susceptible to erratic ground effects than the altimeter.
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You have several cues to establish you are actually off the ground and climbing - the (I)VSI, Baro altimeter, RadAlt and the view out of the window. My normal practice, whatever aircraft I'm in, is to establish two of these before calling "Positive climb". If the view out of the window can be misleading, then I would disregard this and use the others.
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actually when my coffee top shows an angle greater than the horizon..i call for it..except in the sim...too cheap to offer free coffee thren i use the RA or minimum 500ft positive on the vsi
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Hey...I think that's a bogus call. Maybe from the days when most airplanes SE climb ability truly sucked.
But today, most airplanes have very good SE climb ability.
I think it's more of a simulator requirement now.
But today, most airplanes have very good SE climb ability.
I think it's more of a simulator requirement now.
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When I advanced to jet transport flying (altho 4-engine pistons were more fun, IMO), I was trained at PanAmerican on the Boeing 707.
Some of the old straight pipe models (early -320's for example) were very slow climbers at MTOW with an engine inoperative (V2 at 300 feet/min was not uncommon) so the 'positive climb' call was rather important.
These aircraft were equipped with KIFIS, so the v/s was not all that reliable.
PanAmerican insisted that the pressure altimeter be used, and if available, any other secondary indication...radalt for example.
Seemed reasonable to me.
Some of the old straight pipe models (early -320's for example) were very slow climbers at MTOW with an engine inoperative (V2 at 300 feet/min was not uncommon) so the 'positive climb' call was rather important.
These aircraft were equipped with KIFIS, so the v/s was not all that reliable.
PanAmerican insisted that the pressure altimeter be used, and if available, any other secondary indication...radalt for example.
Seemed reasonable to me.
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The early Boeing 737 FCTM (1976) stated "When a positive rate of climb on altimeter and IVSI is observed, the captain will call "Gear Up". From this you can see that there was no verbal input from the first officer to actually call "positive rate". Both of course observed the positive rate but the call positive rate was considered superfluous. I go along with that.
And that's how it should be. Countless times in the simulator we see the PNF forgetting to call positive rate and invariably when this happens the PF dutifully omits to call gear up. It happens on too many occasions to ignore as just one of those things.
We also see many occasions where the PNF will inadvertently forget to call VR. Guess what? most times the PF will continue to trundle merrily down the runway waiting for the Rotate call that never comes until 14-25 knots past V2!. He was unconsciously waiting for a trigger word.
We see the example of one PF who opened up to 40% N1 with brakes released at the beginning of the take off run and trundle down the runway with 40% N1 for over 1500 feet before glancing querously at the PNF and saying accusingly "You haven't said "Stabilised" yet. This is because the parent airline required its PNF to call "Stabilised" when the N1 had reached 40% and stabilised at that figure.
Wherever you have a procedure (such as gear selection) where the one pilot is required to observe something personally then advise the other pilot he has done so before an action is called for, it is a fair bet that the action may not be initiated. The use of two men in the cockpit to take the straight forward action of raising the gear is a prime example. Rarely happens in single pilot aircraft strangely enough.
Best I have seen was during a touch and go landing in the simulator where the instructor called V1, ROTATE, when the aircraft was almost at the far end of the runway and obviously V1 had absolutely no relevance. But he had always called V1, ROTATE together as in most training seqences V1 and VR were within a couple of knots of each other. Pavlov's Dog syndrome in the aviation sense.
Then when you have a decent spread of say 12 knots between V1 and VR, we frequently see the PF start rotating at the call of V1 as he is used to the call being so close to each other. Causes a flurry of rudder activity when an engine is failed at the real V1 and the aircraft is dragged into the air 10 knots below the real VR.
And that's how it should be. Countless times in the simulator we see the PNF forgetting to call positive rate and invariably when this happens the PF dutifully omits to call gear up. It happens on too many occasions to ignore as just one of those things.
We also see many occasions where the PNF will inadvertently forget to call VR. Guess what? most times the PF will continue to trundle merrily down the runway waiting for the Rotate call that never comes until 14-25 knots past V2!. He was unconsciously waiting for a trigger word.
We see the example of one PF who opened up to 40% N1 with brakes released at the beginning of the take off run and trundle down the runway with 40% N1 for over 1500 feet before glancing querously at the PNF and saying accusingly "You haven't said "Stabilised" yet. This is because the parent airline required its PNF to call "Stabilised" when the N1 had reached 40% and stabilised at that figure.
Wherever you have a procedure (such as gear selection) where the one pilot is required to observe something personally then advise the other pilot he has done so before an action is called for, it is a fair bet that the action may not be initiated. The use of two men in the cockpit to take the straight forward action of raising the gear is a prime example. Rarely happens in single pilot aircraft strangely enough.
Best I have seen was during a touch and go landing in the simulator where the instructor called V1, ROTATE, when the aircraft was almost at the far end of the runway and obviously V1 had absolutely no relevance. But he had always called V1, ROTATE together as in most training seqences V1 and VR were within a couple of knots of each other. Pavlov's Dog syndrome in the aviation sense.
Then when you have a decent spread of say 12 knots between V1 and VR, we frequently see the PF start rotating at the call of V1 as he is used to the call being so close to each other. Causes a flurry of rudder activity when an engine is failed at the real V1 and the aircraft is dragged into the air 10 knots below the real VR.
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Agree. Also liked the other examples. I've also experienced the late rotation scenario, much due to the fact that one is so used to responding to a trigger, rather than flying the airplane...
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Some very interesting contributions here... thanks to all....
I had an interesting cockpit discussion one day after calling positive rate (in a Dornier 328 that climbs like a little rocket) based on simple observation of the fact that Planet Earth was visibly shrinking in size on a day that was CAVOK.
The PF, ex-Eastern Airlines, got very upset that I had not waited until the VSI had stabilised on some value or other.
In self-defense I stated that if visual cues were not clearly present then, yes, of course I would have been on the instruments rather than looking out the big windows for vultures, herds of wildebeest or whatever else might be there to be seen.
It was an interesting exploration of two very opposite sets of values, although we were both, perhaps, trying to achieve safety.
I had an interesting cockpit discussion one day after calling positive rate (in a Dornier 328 that climbs like a little rocket) based on simple observation of the fact that Planet Earth was visibly shrinking in size on a day that was CAVOK.
The PF, ex-Eastern Airlines, got very upset that I had not waited until the VSI had stabilised on some value or other.
In self-defense I stated that if visual cues were not clearly present then, yes, of course I would have been on the instruments rather than looking out the big windows for vultures, herds of wildebeest or whatever else might be there to be seen.
It was an interesting exploration of two very opposite sets of values, although we were both, perhaps, trying to achieve safety.
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chuks,
I hope that this jerk never flys one of those 2 engined aircraft that only just meets the climb gradient requirement in the 1st segment following engine failure, i.e. positive. A Rate of Climb of 1 foot per minute is all that's required.
Have seen soooooo many guys in the simulator with an engine failure at V1 under performance limiting conditions, and waiting, waiting, waiting for a positive climb indication before raising the gear...all the way to impact.
This has been an interesting thread. It proves yet again that there are many ways to skin a cat, but MY airline is the only one that does it the right way.
The PF, ex-Eastern Airlines, got very upset that I had not waited until the VSI had stabilised on some value or other.
Have seen soooooo many guys in the simulator with an engine failure at V1 under performance limiting conditions, and waiting, waiting, waiting for a positive climb indication before raising the gear...all the way to impact.
This has been an interesting thread. It proves yet again that there are many ways to skin a cat, but MY airline is the only one that does it the right way.
