Evacuation Decision Model
Thread Starter
Evacuation Decision Model
Hello,
Am just wondering whether anybody has or can direct me to a decision making model as for when to commence an evacuation?
Clearly its not a decision to be taken lightly.
My thoughts: Engine or fuselage fire - Evac.
How about in the wheel well say after an RTO? Would you wait for the fire trucks to arrive to confirm fire under control / isolated or evac anyway?
What about if you had a cargo fire and managed to extinguish successfully the fire (ECAM warnings removed) and put it on the ground. Would you then assume fire has gone out and evac not necessary, or would you consider perhaps the ECAM spurious and thus assume a fire may still be present?
I'm sure I'll get lots of different opinions here and clearly the big picture always needs to be considered but really I'm after a set of thought processes and decision making models / steps you may use when deciding whether or not to evac. for real.
Thank you.
Am just wondering whether anybody has or can direct me to a decision making model as for when to commence an evacuation?
Clearly its not a decision to be taken lightly.
My thoughts: Engine or fuselage fire - Evac.
How about in the wheel well say after an RTO? Would you wait for the fire trucks to arrive to confirm fire under control / isolated or evac anyway?
What about if you had a cargo fire and managed to extinguish successfully the fire (ECAM warnings removed) and put it on the ground. Would you then assume fire has gone out and evac not necessary, or would you consider perhaps the ECAM spurious and thus assume a fire may still be present?
I'm sure I'll get lots of different opinions here and clearly the big picture always needs to be considered but really I'm after a set of thought processes and decision making models / steps you may use when deciding whether or not to evac. for real.
Thank you.
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Good discussion point.
As the PIC, one is primarily responsible for the safety of the crew and pax..
The overriding consideration should be.. Is it safer for them to remain on the aircraft or to evacuate?
Confirmed fire..yes, evacuate. However, smoke only?
One must consider that there is a strong possibility of injury or death during an evacuation using slides.
Utilise all external assets to confirm the status of the emergency and remain onboard if safe ('GRADE').
Imho, an evacuation is the absolute last option to be taken here.
Good discussion point.
As the PIC, one is primarily responsible for the safety of the crew and pax..
The overriding consideration should be.. Is it safer for them to remain on the aircraft or to evacuate?
Confirmed fire..yes, evacuate. However, smoke only?
One must consider that there is a strong possibility of injury or death during an evacuation using slides.
Utilise all external assets to confirm the status of the emergency and remain onboard if safe ('GRADE').
Imho, an evacuation is the absolute last option to be taken here.
Kind of a problem here. I think we can agree that multiple factors and their combinations must be weighed. Computers with data imput do this best for modeling, but while the end result may save more lives, their aint any decision making pilot that is going to risk interpreting what combinations are at play from the hot seat.
I forsee most of the decision making continuing to risk trading egress injuries to lessen the much lower chance of deaths in the cabin.
I forsee most of the decision making continuing to risk trading egress injuries to lessen the much lower chance of deaths in the cabin.
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No time available, direct serious threat to occupants (you are scared for own life) - Evacuate
Some time available, potential threat to occupants (a tad worried about what could happen) - Precautionary
Time available (not worried at all) - Normal disembarkation
Sadly there is no script it all comes down to your judgement and even a subtle change in your circumstances can change the "best decision" but all I can tell you is "any decision beats no decision at all"
Some time available, potential threat to occupants (a tad worried about what could happen) - Precautionary
Time available (not worried at all) - Normal disembarkation
Sadly there is no script it all comes down to your judgement and even a subtle change in your circumstances can change the "best decision" but all I can tell you is "any decision beats no decision at all"
Thread Starter
Thanks for your help guys.
Really got me thinking - this is not a decision to be taken lightly.
Especially when statically there may be a passenger death as a result of evac. (due to injuries).
Having to stand up in court and defend my decisions as being the safest outcome of events has to be the primary driver though.
Really got me thinking - this is not a decision to be taken lightly.
Especially when statically there may be a passenger death as a result of evac. (due to injuries).
Having to stand up in court and defend my decisions as being the safest outcome of events has to be the primary driver though.
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Certain drills / circumstances state an Evacuation is required. Clearly as Capt you can decide not to, but that is a brave decision 
One of my/our criteria is a "Confirmed and Unextinquished Fire" i.e. I will not evacuate for a fire warning that does not go out, but there is no confirmation. Ditto, a fire seen by the tower on an RTO, but my colleague states after firing the bottles the fire light has gone out, I will also hold off.
Do NB it is not an "Evacuate" or "Not Evacuate" decision. There is a middle road of "Not just yet". Whilst the doors are armed, you can be 3s from initiating an evacuation until you disarm them and stand everybody down.
One of my/our criteria is a "Confirmed and Unextinquished Fire" i.e. I will not evacuate for a fire warning that does not go out, but there is no confirmation. Ditto, a fire seen by the tower on an RTO, but my colleague states after firing the bottles the fire light has gone out, I will also hold off.
Do NB it is not an "Evacuate" or "Not Evacuate" decision. There is a middle road of "Not just yet". Whilst the doors are armed, you can be 3s from initiating an evacuation until you disarm them and stand everybody down.
Emergency evacuations may be required:
‐ as a planned evacuation after in-flight emergency,
‐ after an aircraft has suffered severe airframe damage,
‐ where an inextinguishable fire exists or there is an unresolved smoke warning, ‐ as a precautionary procedure.
Situations that may lead to an emergency evacuation include, but are not limited to: ‐ All engine flameout, and/or emergency landing or ditching,
‐ Smoke/Fumes/Avncs Smoke,
‐ Uncontrollable Engine/APU fire,
‐ Cargo Smoke/Fire,
‐ Brake Fire,
‐ Landing Gear collapse,
‐ Fuselage and/or fuel tank rupture.
Captains have the authority to initiate an emergency evacuation when the flight crew perceives a threat to the lives of passengers or emergency conditions exist that jeopardizes their own safety. All available sources of information should be used to determine the safest course of action including reports from the cabin crew, other aircraft, and air traffic control. The Captain must then carefully evaluate and consider all factors and order an emergency evacuation if appropriate. Factors to be considered by the Captain include, but are not limited to: ‐ the urgency of the situation including the possibility of significant injury or loss of life if a significant delay occurs, ‐ the type of threat to the aircraft, including structural damage, fire, reported bomb on board, etc., ‐ the possibility of fire spreading rapidly from spilled fuel or other flammable materials, ‐ the extent of the damage to the aircraft, available exits and passenger loads, ‐ availability and location of RFF equipment, ‐ the possibility of passenger injury during an emergency evacuation using the escape slides.
PLANNED EVACUATIONS If, due to an in-flight emergency, an evacuation is planned and time permits, a thorough briefing and preparation of the crew and passengers improve the chances of a successful evacuation. Flight deck preparations should include a review of pertinent checklists and any other actions to be accomplished.
UNPLANNED EVACUATION DECISION AND EXECUTION An Evacuation Event is defined as any event that may lead to an unplanned evacuation. For unplanned evacuations, the Captain needs to analyze the situation carefully before initiating an evacuation order. Quick actions in a calm and methodical manner will improve the chances of a successful evacuation.
The crew may become aware of an Evacuation Event through:
• ECAM warning • Rejected take-off • Personal observation or Cabin crew report • ATC observation • Other Aircraft observation
‐ as a planned evacuation after in-flight emergency,
‐ after an aircraft has suffered severe airframe damage,
‐ where an inextinguishable fire exists or there is an unresolved smoke warning, ‐ as a precautionary procedure.
Situations that may lead to an emergency evacuation include, but are not limited to: ‐ All engine flameout, and/or emergency landing or ditching,
‐ Smoke/Fumes/Avncs Smoke,
‐ Uncontrollable Engine/APU fire,
‐ Cargo Smoke/Fire,
‐ Brake Fire,
‐ Landing Gear collapse,
‐ Fuselage and/or fuel tank rupture.
Captains have the authority to initiate an emergency evacuation when the flight crew perceives a threat to the lives of passengers or emergency conditions exist that jeopardizes their own safety. All available sources of information should be used to determine the safest course of action including reports from the cabin crew, other aircraft, and air traffic control. The Captain must then carefully evaluate and consider all factors and order an emergency evacuation if appropriate. Factors to be considered by the Captain include, but are not limited to: ‐ the urgency of the situation including the possibility of significant injury or loss of life if a significant delay occurs, ‐ the type of threat to the aircraft, including structural damage, fire, reported bomb on board, etc., ‐ the possibility of fire spreading rapidly from spilled fuel or other flammable materials, ‐ the extent of the damage to the aircraft, available exits and passenger loads, ‐ availability and location of RFF equipment, ‐ the possibility of passenger injury during an emergency evacuation using the escape slides.
PLANNED EVACUATIONS If, due to an in-flight emergency, an evacuation is planned and time permits, a thorough briefing and preparation of the crew and passengers improve the chances of a successful evacuation. Flight deck preparations should include a review of pertinent checklists and any other actions to be accomplished.
UNPLANNED EVACUATION DECISION AND EXECUTION An Evacuation Event is defined as any event that may lead to an unplanned evacuation. For unplanned evacuations, the Captain needs to analyze the situation carefully before initiating an evacuation order. Quick actions in a calm and methodical manner will improve the chances of a successful evacuation.
The crew may become aware of an Evacuation Event through:
• ECAM warning • Rejected take-off • Personal observation or Cabin crew report • ATC observation • Other Aircraft observation
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Regarding Fumes/Fire and evacuation the following incident comes to mind, as published on the AAIB website here
It is a great case study for CRM training.
Synopsis:
Extracts
Summary
It is a great case study for CRM training.
Synopsis:
Shortly after landing, smoke was observed in both the cockpit and cabin. The aircraft was stopped, the engines were shut down and an evacuation was carried out. No technical defect was found during the subsequent examination. It is probable that the smoke was caused by the engines ingesting granular urea, which had been used to de-ice the runway during a very cold weather period.
The aircraft was inspected and no defect or technical anomaly was found which could explain the presence of smoke during the landing roll.
The runway and taxiway were inspected by the Investigation the following morning. These had been swept clear of snow, which had been removed to the sides of the runway. The centre section of the runway was bare and clear but found to be lightly covered by significant amounts of granular urea that had been spread on the runway by a mechanical spreader.
Older runway de-icing/anti-icing methods, such as the application of urea or glycol, are no longer used as they have been replaced by more modern methods that are more environmentally friendly in the main. In addition, chloride salts, commonly used on roads etc., cannot be used where aircraft move due to their corrosive effect on aircraft structures and systems.
Urea granules are colourless, odourless and have a melting point of 132.7C. A sample of the granular urea used on the runway was obtained, which was heated using hot air. It initially melted to a clear liquid that subsequently boiled with an acrid and pungent smell (ammonia is released on contact with the water vapour in the air). A grey hue was observed in the air and a powdery residue remained after the liquid had evaporated.
When urea is used as an anti-ice formation agent, precipitation (snow or rain) falling on the urea dissolves it. The resulting mixture has a lower freezing point. Though effective down to -9.5C it is of limited use at temperatures below -4C.
In general liquid potassium acetate (KAc) is used at Irish Airports as an anti-icing agent. This can also be spread in conjunction with urea (hopper spread beforehand), in which case KAc dissolves the urea granules. Since supplies of KAc were exhausted by the time of the incident urea was used on its own.
The runway and taxiway were inspected by the Investigation the following morning. These had been swept clear of snow, which had been removed to the sides of the runway. The centre section of the runway was bare and clear but found to be lightly covered by significant amounts of granular urea that had been spread on the runway by a mechanical spreader.
Older runway de-icing/anti-icing methods, such as the application of urea or glycol, are no longer used as they have been replaced by more modern methods that are more environmentally friendly in the main. In addition, chloride salts, commonly used on roads etc., cannot be used where aircraft move due to their corrosive effect on aircraft structures and systems.
Urea granules are colourless, odourless and have a melting point of 132.7C. A sample of the granular urea used on the runway was obtained, which was heated using hot air. It initially melted to a clear liquid that subsequently boiled with an acrid and pungent smell (ammonia is released on contact with the water vapour in the air). A grey hue was observed in the air and a powdery residue remained after the liquid had evaporated.
When urea is used as an anti-ice formation agent, precipitation (snow or rain) falling on the urea dissolves it. The resulting mixture has a lower freezing point. Though effective down to -9.5C it is of limited use at temperatures below -4C.
In general liquid potassium acetate (KAc) is used at Irish Airports as an anti-icing agent. This can also be spread in conjunction with urea (hopper spread beforehand), in which case KAc dissolves the urea granules. Since supplies of KAc were exhausted by the time of the incident urea was used on its own.
At the time of the incident the weather in Ireland had been unseasonably cold for the previous month. Because of this, the supplies of runway de-icing fluid had been exhausted at EIKY and, if airport operations were to continue, granular urea was one of the few alternatives available. This was spread on the runway as an anti-icing measure in order to allow continued safe operation of flights from the runway. In this case, although some snow had been expected, none had fallen and consequently the urea had not dissolved and significant amounts remained in granular form on the centre of the runway, which was bare and clear of snow.
After landing, the engines spooled up due to reverse thrust being selected, as per normal procedures. It is probable that the urea on the runway was then ingested into the engines and rapidly heated to a high temperature by engine compression before being dispensed by the air conditioning system throughout the flight deck and cabin.
This would have resulted in the acrid smoke observed in both the cockpit and cabin.
After landing, the engines spooled up due to reverse thrust being selected, as per normal procedures. It is probable that the urea on the runway was then ingested into the engines and rapidly heated to a high temperature by engine compression before being dispensed by the air conditioning system throughout the flight deck and cabin.
This would have resulted in the acrid smoke observed in both the cockpit and cabin.
