Check list concept of challenge and response
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Check list concept of challenge and response
The original concept of a checklist in a multi crew aircraft required one person to challenge and the second person responded. This policy ensured as far as possible, that no item was missed. After all, two people were involved.
This proven concept was thrown out of the cockpit window with the introduction of fly-by-wire modern jet transports. Aircraft manufacturers have gone away from the original concept and designed checklists based upon so called "Area of Responsibility". At the request of the captain (or PF) a first officer might read a checklist by first calling aloud (challenge) the checklist item; then reply to his own challenge without any input (reply) by the captain.
What often happens is the captain hears the first challenge and then the self response by his F/O but without any verbal confirmation from the captain. This often leads to complacency, where, instead of being actively involved with the checklist, the non-responder simply scratches his balls and impatiently waits for the other guy finish challenging and responding to himself. In some Boeing types for example, the majority of checklist items are read by the PM as a challenge and response to himself. There seems little point in calling the policy "Challenge and Response" when done by the checklist reader challenging himself and responding to himself that he has done the job.
The original concept of one pilot challenging while the other pilot confirmed (after checking the switch position etc), was once hailed as a major improvement in flight safety. The change from a seemingly fool-proof flight safety concept to what is now basically a one man band concept is called progress? . ?
This proven concept was thrown out of the cockpit window with the introduction of fly-by-wire modern jet transports. Aircraft manufacturers have gone away from the original concept and designed checklists based upon so called "Area of Responsibility". At the request of the captain (or PF) a first officer might read a checklist by first calling aloud (challenge) the checklist item; then reply to his own challenge without any input (reply) by the captain.
What often happens is the captain hears the first challenge and then the self response by his F/O but without any verbal confirmation from the captain. This often leads to complacency, where, instead of being actively involved with the checklist, the non-responder simply scratches his balls and impatiently waits for the other guy finish challenging and responding to himself. In some Boeing types for example, the majority of checklist items are read by the PM as a challenge and response to himself. There seems little point in calling the policy "Challenge and Response" when done by the checklist reader challenging himself and responding to himself that he has done the job.
The original concept of one pilot challenging while the other pilot confirmed (after checking the switch position etc), was once hailed as a major improvement in flight safety. The change from a seemingly fool-proof flight safety concept to what is now basically a one man band concept is called progress? . ?
Last edited by Tee Emm; 23rd Dec 2017 at 11:22.
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Well on my type (A320) the only checklist that is "self-responded" is the After Landing Checklist (and this is also depending on the operator - some do it as a challenge-response checklist while other do it "self-responded"), which is deemed to be not very critical (the worst case would probably be forgetting to switch off the weather radar but with engines shutdown it will be automatically shutdown anyway independent of switch position - otherwise its just the embarrassment of arriving on stand with Spoilers/Flaps still out). There are some items that are considered more critical that require and answer from both crew members, but the PM will wait for the PFs answer before replying (f.e. PM: "cockpit preparation" PF (verifies the item): "completed" PM (verifies the item as well: "completed"). I agree with you that answering your own challenge is a practice that is error-prone.
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Tee Emm,
The original challenge/response was only one type of checklist that can be used by an operator (challenge/response, read & do, do & say, etc.) Each checklist is a tool that is best used at different times and the operator will determine what level of "check" is required. An operator may even mix checklist types where it is determined a level of oversight is required (e.g. a landing checklist that is done as a read & do except for the landing gear and flaps, conducted as a challenge/response).
When designing checklists for my last operator, I would take the AOM and sit down with all our management and training pilots to identify better ways of managing the checklists and the items within them. Often we would ask "do we really want this handled by just the one pilot?" If the answer was no, then we made it a challenge/response item. It the answer was "does it really matter," then we would discuss what method worked best for the anticipated cockpit workload when the checklist was to be actioned.
For example, what is the point of a challenge/response checklist is at FL350 where the only steps might be "cruise power, weather radar, seatbelt signs." There is none; none of these are critical flight safety items, ergo they don't need the same level of oversight that, say the after start checklist requires where the flaps are being deployed.
Discipline is a big part of managing checklists though, and you're right that an improperly handled read & do does no one any good. This is where the Captain must step in and force the First Officer to do it properly and do it properly him/herself. If done overtime, the First Officer will learn and ultimately become the Captain forcing a newer First Officer. I'd say 15% of my pairings have me asking the First Officer to re-do the checklist by grabbing it from the holder rather than relying on their memory.
The original challenge/response was only one type of checklist that can be used by an operator (challenge/response, read & do, do & say, etc.) Each checklist is a tool that is best used at different times and the operator will determine what level of "check" is required. An operator may even mix checklist types where it is determined a level of oversight is required (e.g. a landing checklist that is done as a read & do except for the landing gear and flaps, conducted as a challenge/response).
When designing checklists for my last operator, I would take the AOM and sit down with all our management and training pilots to identify better ways of managing the checklists and the items within them. Often we would ask "do we really want this handled by just the one pilot?" If the answer was no, then we made it a challenge/response item. It the answer was "does it really matter," then we would discuss what method worked best for the anticipated cockpit workload when the checklist was to be actioned.
For example, what is the point of a challenge/response checklist is at FL350 where the only steps might be "cruise power, weather radar, seatbelt signs." There is none; none of these are critical flight safety items, ergo they don't need the same level of oversight that, say the after start checklist requires where the flaps are being deployed.
Discipline is a big part of managing checklists though, and you're right that an improperly handled read & do does no one any good. This is where the Captain must step in and force the First Officer to do it properly and do it properly him/herself. If done overtime, the First Officer will learn and ultimately become the Captain forcing a newer First Officer. I'd say 15% of my pairings have me asking the First Officer to re-do the checklist by grabbing it from the holder rather than relying on their memory.
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This proven concept was thrown out of the cockpit window with the introduction of fly-by-wire modern jet transports. Aircraft manufacturers have gone away from the original concept and designed checklists based upon so called "Area of Responsibility". At the request of the captain (or PF) a first officer might read a checklist by first calling aloud (challenge) the checklist item; then reply to his own challenge without any input (reply) by the captain.
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I haven't read that in the FCOM? Wouldn't it work with the engines off in case the engineers need to test it?
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Responding from the memory of the thrown switch (or even pure imagination) rather than the actual checking of its current position. I agree it's a problem. But doing it by 2-pilot challenge and response is no guarantee of fixing it. The responder can still respond from imagination, but at least now both pilots (as opposed to just one) would have to slack off to let a problem slip through... so at least it's some improvement.
The worst I remember is one captain, who would respond to the entire shutdown checklist while turned mostly backwards packing his bag. Literally every switch on the list could have been in the wrong position and it would have stayed that way.
The worst I remember is one captain, who would respond to the entire shutdown checklist while turned mostly backwards packing his bag. Literally every switch on the list could have been in the wrong position and it would have stayed that way.
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The responder can still respond from imagination, but at least now both pilots (as opposed to just one) would have to slack off to let a problem slip through... so at least it's some improvement.
For example, during the after takeoff checklist, we are required to look at and touch the bleed air switches to make sure they're on, and then touch the pressurization switch to make sure it's in auto. I swear they did everything but have a wooden spoon in the sim when they added that to the SOP and I still feel as though I'm being watched when I fly the line.
