The danger of the F/O calling STOP before V1
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The danger of the F/O calling STOP before V1
During recent type rating training on a 737 with pilots inducted into an airline, the syllabus called for demonstration of an outboard tyre failure 20 knots below V1. The pre-flight briefing included the advice that it is normally safer to continue the take off, rather than risk a high speed abort with degraded braking.
Despite this, when the tyre failed with noticeable vibration, the first officer called "STOP" and the captain under training immediately rejected the take off.
Both pilots had come from an operator where a rejected take off could be initiated if either pilot called "STOP" -without giving the reason for the call.
I understand this policy is common SOP at many airlines - the theory being the PNF may spot a problem which, in his personal opinion, requires an abort and that the other pilot was not aware of.
The B737 FCTM puts a different light on the subject by saying "the PM should closely monitor essential instruments during the take of roll and immediately announce abnormalities such as ENGINE FIRE, ENGINE FAILURE, or any adverse condition significantly affecting the safety of flight. The decision to reject the take off is the responsibility of the captain and must be made before V1 speed. If the captain is the PM, he should initiate the RTO and announce the abnormality simultaneously".
The executive word "STOP" as used by some operators, carries with it an awesome responsibility. A company policy that requires the captain to initiate an abort purely on another crew member's personal opinion, is fraught with legal issues. Perhaps that is why Boeing - ever vigilant to the risks of litigation - have not recommended the PM call "STOP" to start the rejected take off chain of events - but instead recommend the PM announce the problem rather than have the authority to call "STOP" with the full expectation the captain will follow his (the PM's) command.
I wonder how many captains crewed with an inexperienced first officer (quite common nowadays from reading Pprune) have been stunned to hear an F/O call "STOP" for a perceived serious problem, and have retorted "You have to be kidding" -and kept on going.
There are risks in any take off and a personal opinion call of "STOP" must be one of them. Personally, this scribe prefers the Boeing advice..
Thoughtful discussion appreciated.
Despite this, when the tyre failed with noticeable vibration, the first officer called "STOP" and the captain under training immediately rejected the take off.
Both pilots had come from an operator where a rejected take off could be initiated if either pilot called "STOP" -without giving the reason for the call.
I understand this policy is common SOP at many airlines - the theory being the PNF may spot a problem which, in his personal opinion, requires an abort and that the other pilot was not aware of.
The B737 FCTM puts a different light on the subject by saying "the PM should closely monitor essential instruments during the take of roll and immediately announce abnormalities such as ENGINE FIRE, ENGINE FAILURE, or any adverse condition significantly affecting the safety of flight. The decision to reject the take off is the responsibility of the captain and must be made before V1 speed. If the captain is the PM, he should initiate the RTO and announce the abnormality simultaneously".
The executive word "STOP" as used by some operators, carries with it an awesome responsibility. A company policy that requires the captain to initiate an abort purely on another crew member's personal opinion, is fraught with legal issues. Perhaps that is why Boeing - ever vigilant to the risks of litigation - have not recommended the PM call "STOP" to start the rejected take off chain of events - but instead recommend the PM announce the problem rather than have the authority to call "STOP" with the full expectation the captain will follow his (the PM's) command.
I wonder how many captains crewed with an inexperienced first officer (quite common nowadays from reading Pprune) have been stunned to hear an F/O call "STOP" for a perceived serious problem, and have retorted "You have to be kidding" -and kept on going.
There are risks in any take off and a personal opinion call of "STOP" must be one of them. Personally, this scribe prefers the Boeing advice..
Thoughtful discussion appreciated.
I understand this policy is common SOP at many airlines
Been done to death on this forum in the recent past and people from both camps are convinced they use the correct method.
Perhaps that is why Boeing - ever vigilant to the risks of litigation - have not recommended the PM call "STOP" to start the rejected take off chain of events - but instead recommend the PM announce the problem rather than have the authority to call "STOP" with the full expectation the captain will follow his (the PM's) command.
As an F/O, I agree with it. Circumstances have to be analysed and decisions made in such a short space of time that the decision should be down to one man (or woman) alone. Having two people trying to make different decisions in such a critical stage of the operation while barrelling towards V1 is a recipe for disaster. Leave it to the commander.
In a recent sim check we discussed the unlikely but feasible scenario of a commander becoming incapacitated on the take-off roll. Even in this situation the outcome was that the F/O should continue, get airborne, take whatever time is needed then return and land; the logic being that the F/O is not trained in the physical handling of the aircraft during an RTO but should be well practiced in landing. That gives you an idea as to how the company view the risks associated with an RTO.
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100% with you on this. Only the Captain (or more correctly,the pilot in command) should use the call of STOP in my opinion. In fairness, I usually catch any difference to this at the departure briefing stage, when FOs are PF and often state "after 80 knots I will call STOP for......" At this point I will interrupt and make it absolutely clear that they should assertively announce any problem but NOT mention the word STOP.
However....
The airline I have been working for recently, supports the method of FOs being able to call STOP. Fortunately, this is not evident in any of the company's Operations Manuals, NOTACs or Memos and is merely hearsay from the Training Department so I continue to politely deny the existence of any such responsibility other than from the PIC.
I remember a refuelling panel (door flap position) caution illuminating during a take off roll some years ago when I was an FO. I recall discussing with the Captain in the cruise that I thought we should have stopped for it; however he explained to me why it was safe to continue. I went away from that day with some more experience and knowledge under my belt, not least the realisation that I was at the time, still too inexperienced and unfamiliar with the aircraft to have the confidence or responsibility to call STOP, and that's why they trained me not to say it in the first place!
Sometimes new CRM methods can disrupt common sense operating. I for one will remain a stuffy old fashioned git on this one.
However....
The airline I have been working for recently, supports the method of FOs being able to call STOP. Fortunately, this is not evident in any of the company's Operations Manuals, NOTACs or Memos and is merely hearsay from the Training Department so I continue to politely deny the existence of any such responsibility other than from the PIC.
I remember a refuelling panel (door flap position) caution illuminating during a take off roll some years ago when I was an FO. I recall discussing with the Captain in the cruise that I thought we should have stopped for it; however he explained to me why it was safe to continue. I went away from that day with some more experience and knowledge under my belt, not least the realisation that I was at the time, still too inexperienced and unfamiliar with the aircraft to have the confidence or responsibility to call STOP, and that's why they trained me not to say it in the first place!
Sometimes new CRM methods can disrupt common sense operating. I for one will remain a stuffy old fashioned git on this one.
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As mentioned, this subject has been srutinized closely and at length in these forums. A search of 'FO call STOP' brings a wealth of topics, if you take the time to peruse them!
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1) How was the tyre burst simulated?
2) Was this training or a check ride?
3) Were the crew members properly briefed and practiced in the new companies procedures.
One incident in a sim session is no reason to drop the litter. You have to allow people to learn before you can expect them to know.
I would worry more about the training methods than the pilots performance if I were you.
2) Was this training or a check ride?
3) Were the crew members properly briefed and practiced in the new companies procedures.
One incident in a sim session is no reason to drop the litter. You have to allow people to learn before you can expect them to know.
I would worry more about the training methods than the pilots performance if I were you.
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I hope there is more to that training that a simple simulator demo, or a set of them...
Consider the single simple fact that a tire failure on a 737 will effectively reduce braking ability by almost 25% (1 of 4 tires with brakes), while on a 747 it would be closer to 6% (1 of 16 tires with brakes). The stop distance for the 737 would be increased considerably, so if there is not much stop margin to begin with, a rejected takeoff even 20 Kt below V1 could well result in an overrun...
Consider the single simple fact that a tire failure on a 737 will effectively reduce braking ability by almost 25% (1 of 4 tires with brakes), while on a 747 it would be closer to 6% (1 of 16 tires with brakes). The stop distance for the 737 would be increased considerably, so if there is not much stop margin to begin with, a rejected takeoff even 20 Kt below V1 could well result in an overrun...
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so if there is not much stop margin to begin with, a rejected takeoff even 20 Kt below V1 could well result in an overrun...
With our ops, the First Officer is tasked with the duties of calling the reason for STOP, and the Captain is tasked for stopping the airplane, IF necessary, in HIS judgement.
Works for us, quite well.
If an operator empowers a pilot to decide on course of action (call stop), in a time critical event, then it essential that the procedure and crew’s activities are well defined.
This requires that the circumstances for an RTO be clearly defined.
Certification regulations focus on engine failure – loss of thrust (fire etc). Operational issues have been added to this, often without sufficient thought in the process of detecting and assessing the failure.
Thus the first point might be – how do you know it is a tyre failure?
Engine ‘failure’ is reasonably easy to define and thus the decision tends to be an “if - then” activity. However, with other failures the situation is rarely clear cut, e.g. a 'bang', tyre failure or engine surge; – some would argue that neither warrants an RTO in a time critical situation, i.e. at high speed.
Thus the decision process may depend on the stage of the take off.
Does P2 call stop below 80 / 100kts? Or because there is relatively more time for assessment is the decision up to the Captain?
From this example the P2’s duties might be simplified to calling stop only for an engine failure (as defined by the procedure), and only at high speed.
It may be preferable for the decision maker to be the same person as the actor; a subconscious decision may already be in action before the verbal decision is given.
However, this may have complications with Captain-only actions and P2 handling.
Alternatively this arrangement enables the monitoring pilot to aid situation assessment; the call can describe the situation on which the decision maker can act.
On balance it may be better to accept a small delay in change of control for P2 take offs, traded by possibly greater experience of the decision maker.
At high speed, a time critical decision should be biased towards a GO mindset.
When and how is the experience necessary to reinforce this mindset acquired by a pilot; can you be sure that a P2 has reached the required standard?
This requires that the circumstances for an RTO be clearly defined.
Certification regulations focus on engine failure – loss of thrust (fire etc). Operational issues have been added to this, often without sufficient thought in the process of detecting and assessing the failure.
Thus the first point might be – how do you know it is a tyre failure?
Engine ‘failure’ is reasonably easy to define and thus the decision tends to be an “if - then” activity. However, with other failures the situation is rarely clear cut, e.g. a 'bang', tyre failure or engine surge; – some would argue that neither warrants an RTO in a time critical situation, i.e. at high speed.
Thus the decision process may depend on the stage of the take off.
Does P2 call stop below 80 / 100kts? Or because there is relatively more time for assessment is the decision up to the Captain?
From this example the P2’s duties might be simplified to calling stop only for an engine failure (as defined by the procedure), and only at high speed.
It may be preferable for the decision maker to be the same person as the actor; a subconscious decision may already be in action before the verbal decision is given.
However, this may have complications with Captain-only actions and P2 handling.
Alternatively this arrangement enables the monitoring pilot to aid situation assessment; the call can describe the situation on which the decision maker can act.
On balance it may be better to accept a small delay in change of control for P2 take offs, traded by possibly greater experience of the decision maker.
At high speed, a time critical decision should be biased towards a GO mindset.
When and how is the experience necessary to reinforce this mindset acquired by a pilot; can you be sure that a P2 has reached the required standard?
I think for 411A's method is the best---the FO says Engine Failure---Captain decides whether or not not stop---trouble with it is that it requires that both crew-members are pilots
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If the FO can't call stop what is he doing there. Let's make it a single crew operation and make it easier for everyone. If your company training is so poor that a professional pilot can't make a Stop/Decision maybe there's a need for an overhaul in your trg dept.
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I think my previous company has it about right for the B747-400:
either pilot will call stop for:
+ Any fire
+ Any engine failure confirmed by 2 parameters, at least one must be internal (eg swing or bang plus N1 decrease)
+ configuration warning
+ "Windshear ahead" warning
+ "Monitor Radar Display" caution
additionally, when the co-pilot is handling pilot, he may call stop for:
+ Significant handling difficulty
+ blocked runway
anything else the FO sees is brought to the captains notice for a decision.
=========================
At the call of "STOP" whoever is handling will commence the recall items of the REJECTED TAKEOFF checklist.
+ for the handling pilot (close thrust levers/disc A/T /confirm RTO brake operation else apply max manual brakes)
+ for the non-handling pilot (selects rev idle/confirmsSpeedbrake deployed else deploys them/ above xxkts selects all available reverse.
Then it reverts to Captain and FO drills (with the Captain assuming control if the FO had been handling pilot) and the stop and poss evac items are completed.
In this way the stopping is commenced as soon as possible, governed by a strict set of requirements, with no superfluous cross-cockpit passing of the decision making process.
NB FO if handling handles the thrust levers.
Note: not expecting approval from certain quarters
either pilot will call stop for:
+ Any fire
+ Any engine failure confirmed by 2 parameters, at least one must be internal (eg swing or bang plus N1 decrease)
+ configuration warning
+ "Windshear ahead" warning
+ "Monitor Radar Display" caution
additionally, when the co-pilot is handling pilot, he may call stop for:
+ Significant handling difficulty
+ blocked runway
anything else the FO sees is brought to the captains notice for a decision.
=========================
At the call of "STOP" whoever is handling will commence the recall items of the REJECTED TAKEOFF checklist.
+ for the handling pilot (close thrust levers/disc A/T /confirm RTO brake operation else apply max manual brakes)
+ for the non-handling pilot (selects rev idle/confirmsSpeedbrake deployed else deploys them/ above xxkts selects all available reverse.
Then it reverts to Captain and FO drills (with the Captain assuming control if the FO had been handling pilot) and the stop and poss evac items are completed.
In this way the stopping is commenced as soon as possible, governed by a strict set of requirements, with no superfluous cross-cockpit passing of the decision making process.
NB FO if handling handles the thrust levers.
Note: not expecting approval from certain quarters
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The Kakaba
I think it works better because:
1. It splits the initial actions more evenly and allows the HP to concentrate more on the tracking and braking while looking outside.
2. The NHP gets the correct sequence of rev idle, speedbrakes then up (manually if necessary), to max reverse concentrating initially inside the cockpit.
To add; in general terms I think it is good for the FO to get used to the decision making processes early on, then in the aforementioned mode of operating, whe converting to the LHS as Captain, it is just an incremental change of responsibility and not a whole new ballgame.
I think it works better because:
1. It splits the initial actions more evenly and allows the HP to concentrate more on the tracking and braking while looking outside.
2. The NHP gets the correct sequence of rev idle, speedbrakes then up (manually if necessary), to max reverse concentrating initially inside the cockpit.
To add; in general terms I think it is good for the FO to get used to the decision making processes early on, then in the aforementioned mode of operating, whe converting to the LHS as Captain, it is just an incremental change of responsibility and not a whole new ballgame.
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The Term "Stop" or "Abort"
Centaurus:
The "old fashion" standards that stood the test of time were as follows:
"Emergency Drills and Procedures: A malfunction during a critical phase of flight, i.e requiring immediate action tasks by recall, should be positively announced by the observing crew member. As time permits, the other crew member should make every effort to confirm / identify the malfunction before initiating emergency action. On take-off, for example, the PNF usually is the first to observe any indication of a critical failure. Upon observing such indication, he announces it and simultaneously verifies the malfunction graphically to the PF (pointing to the indicator / annunciator )
On verification of the malfunction, the PF announces his decision and commands accomplishment of recall action items, monitoring the PNF in those tasks accomplished by him.
The take-off stop / abort manoeuvre is made only by the Commander."
Tmb
The "old fashion" standards that stood the test of time were as follows:
"Emergency Drills and Procedures: A malfunction during a critical phase of flight, i.e requiring immediate action tasks by recall, should be positively announced by the observing crew member. As time permits, the other crew member should make every effort to confirm / identify the malfunction before initiating emergency action. On take-off, for example, the PNF usually is the first to observe any indication of a critical failure. Upon observing such indication, he announces it and simultaneously verifies the malfunction graphically to the PF (pointing to the indicator / annunciator )
On verification of the malfunction, the PF announces his decision and commands accomplishment of recall action items, monitoring the PNF in those tasks accomplished by him.
The take-off stop / abort manoeuvre is made only by the Commander."
Tmb
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If the FO can't call stop what is he doing there. Let's make it a single crew operation and make it easier for everyone. If your company training is so poor that a professional pilot can't make a Stop/Decision maybe there's a need for an overhaul in your trg dept.
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I think for 411A's method is the best---the FO says Engine Failure---Captain decides whether or not not stop---trouble with it is that it requires that both crew-members are pilots
As an F/O on the 747 (100 & 200), both myself and the F/E were trained, and expected, to call out the problem, but then let the captain make the decision.
As a DC8 captain I had PFE's (Professional Flight Engineers) who had never been pilots, nor had they any intentions to be. They "called" a problem if they saw it, and I decided if stopping was necessary (We used to call it "Abort" until someone became too politically sensitive about the word).
On the A330/A340 the FEs doesn't exist anymore, and I for one, miss having them.
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Whenever I see this argument come up again and again the only common issue for me is that there is a general lack of understanding as to what the difference is between "doing something" and "saying something" and "being responsible for something".
The closer one gets to V1, the less time is available for discussion.
Everyone seems to be clear on this aspect. However, few seem to remember that at slightly lower speeds there is the problem that calling continue can cause a bigger problem.
The rejeted take-off figures for the aircraft are always based on a set criteria and include very specific time intervals between failure and decision to continue or stop and if stopping the initial actions to do so.
To look at the situation very simply, whoever has the throttles in their hands must be able to call stop because as most people will have experienced (in the sim if not in real life) that while the intention is usually - "stop stop", throttles closed - in reality the closing of the throttles can often lead the call.
I have seen lots of operators in the sim where one called stop, the aircraft was stopped and the other looked across and asked "why did we stop?" - happens especially on a 3 engine aircraft when the middle one starts to run-down at V1-10.
So personally I don't see any problem with either crewmember calling stop or the alternative of only the PIC calling stop. However, what I do have a problem with is the idea that there should be some conversation / discussion / interpretation involved in the procedure.
The person who can't call stop should never be expected to have some long winded failure call eg EGT high engine 3 or N1 reducing engine 2 or even I believe use the word "failure" because that word leads the other crew member down a specific thought path which might not be correct.
Fire
Engine
Danger
are examples of key words that should be used alone because they are short, clear, not open to interpretation and we don't require the person who is tasked with making the decision to take-in, interpret and confirm what was said, digest that and come up with some decision.
Now hands up all the Captains who at V1-10 whiler PF are not going to stop when the FO calls Engine (or any of the key words?). Hands up those that are going to look inside to see what the problem is?
However, it is critical if only the PIC can call stop that they have the throttles in their hands at all times.
This leads to another issue;
While Captain is sitting there keeping the throttles up as the FO (PF) calls "SMOKE" - which you can't see do you think that at V1-10 they (the FO) will slam on the brakes that are right there under their feet? if they can see smoke coming from the panel down by their right leg which you can't see?........do you think you want to search out the smoke before saying stop? do you want to get airbourne with a cockpit fire????
Does it make any difference if the FO calls "Smoke" or "Stop"?
Personally, I find that the best option is that anyone can call stop (no debate required as to why stopping) but the PIC can override that decision if they believe that it would be unsafe to stop. This method generally provides the quickest reactions and the shortest stop distances.
Therefore in the example that started this debate the FO called "stop", the PIC (if they recognised that it was a tire failure and it's safer to continue) would have said "Continue" and the flight would have got airbourne. The problem described is not because of the call, because of responsibility or because of procedurs it is because neither pilot recognised the situation correctly.
Perhaps we should have had:
FO "Thrust Set"
FO "80 Knots"
PIC "Checked"
...........
FO "Loud bang Captain"
PIC "What Banged?"
FO " I don't know"
PIC "Stop Stop"
FO "but V1 was 10 knots ago we are already 5 knots above Vr"
Bang
FO "Another Loud bang Captain"
PIC "What Banged?"
FO "we did through the airfield fence"
The closer one gets to V1, the less time is available for discussion.
Everyone seems to be clear on this aspect. However, few seem to remember that at slightly lower speeds there is the problem that calling continue can cause a bigger problem.
The rejeted take-off figures for the aircraft are always based on a set criteria and include very specific time intervals between failure and decision to continue or stop and if stopping the initial actions to do so.
To look at the situation very simply, whoever has the throttles in their hands must be able to call stop because as most people will have experienced (in the sim if not in real life) that while the intention is usually - "stop stop", throttles closed - in reality the closing of the throttles can often lead the call.
I have seen lots of operators in the sim where one called stop, the aircraft was stopped and the other looked across and asked "why did we stop?" - happens especially on a 3 engine aircraft when the middle one starts to run-down at V1-10.
So personally I don't see any problem with either crewmember calling stop or the alternative of only the PIC calling stop. However, what I do have a problem with is the idea that there should be some conversation / discussion / interpretation involved in the procedure.
The person who can't call stop should never be expected to have some long winded failure call eg EGT high engine 3 or N1 reducing engine 2 or even I believe use the word "failure" because that word leads the other crew member down a specific thought path which might not be correct.
Fire
Engine
Danger
are examples of key words that should be used alone because they are short, clear, not open to interpretation and we don't require the person who is tasked with making the decision to take-in, interpret and confirm what was said, digest that and come up with some decision.
Now hands up all the Captains who at V1-10 whiler PF are not going to stop when the FO calls Engine (or any of the key words?). Hands up those that are going to look inside to see what the problem is?
However, it is critical if only the PIC can call stop that they have the throttles in their hands at all times.
This leads to another issue;
While Captain is sitting there keeping the throttles up as the FO (PF) calls "SMOKE" - which you can't see do you think that at V1-10 they (the FO) will slam on the brakes that are right there under their feet? if they can see smoke coming from the panel down by their right leg which you can't see?........do you think you want to search out the smoke before saying stop? do you want to get airbourne with a cockpit fire????
Does it make any difference if the FO calls "Smoke" or "Stop"?
Personally, I find that the best option is that anyone can call stop (no debate required as to why stopping) but the PIC can override that decision if they believe that it would be unsafe to stop. This method generally provides the quickest reactions and the shortest stop distances.
Therefore in the example that started this debate the FO called "stop", the PIC (if they recognised that it was a tire failure and it's safer to continue) would have said "Continue" and the flight would have got airbourne. The problem described is not because of the call, because of responsibility or because of procedurs it is because neither pilot recognised the situation correctly.
Perhaps we should have had:
FO "Thrust Set"
FO "80 Knots"
PIC "Checked"
...........
FO "Loud bang Captain"
PIC "What Banged?"
FO " I don't know"
PIC "Stop Stop"
FO "but V1 was 10 knots ago we are already 5 knots above Vr"
Bang
FO "Another Loud bang Captain"
PIC "What Banged?"
FO "we did through the airfield fence"