BAE146 emergency exits
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BAE146 emergency exits
hi there
on a recent trip on a BAE 146 i noticed that on the evacuation sheets there was a display of the exits to use should one need to evacuate on land and on water.
Now on land all 4 doors are used but on water only the forward 2 doors are used according to the sheet.
My question is this....
should the fact that the forward doors are the only ones which are allowed to be used on a water landing limit the amount of passengers that can be transported.
I know i know you will say the chances of it having to land on water is remote/plus losing all 4 engines but if it should happen would this not restrict the amount of passengers the aircraft could carry since only "x" amount can evacute through the doors at any 1 time span.
I worked on the ground for a while and a few times when a plane was being dispatched it came to light that 1 of the emergency doors was inop....resulting in the fact that x number of rows could not be used due the the evacuation policy.
so should this not affect the BAE146 to the same extent??
on a recent trip on a BAE 146 i noticed that on the evacuation sheets there was a display of the exits to use should one need to evacuate on land and on water.
Now on land all 4 doors are used but on water only the forward 2 doors are used according to the sheet.
My question is this....
should the fact that the forward doors are the only ones which are allowed to be used on a water landing limit the amount of passengers that can be transported.
I know i know you will say the chances of it having to land on water is remote/plus losing all 4 engines but if it should happen would this not restrict the amount of passengers the aircraft could carry since only "x" amount can evacute through the doors at any 1 time span.
I worked on the ground for a while and a few times when a plane was being dispatched it came to light that 1 of the emergency doors was inop....resulting in the fact that x number of rows could not be used due the the evacuation policy.
so should this not affect the BAE146 to the same extent??
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There are quite a few aircraft for which there is a restriction on which doors may be used in case of ditching. As a passenger, it's one of the first things I check on the safety card after sitting down!
On the Fokker 50, there are boards the CC are supposed to instal at the door sill level before opening them after a ditching. That always seemed to be to be a triumph of optimism over common sense.
I've never seen a case of an aircraft ditching successfully that didn't go down within a matter of minutes or less. So it wouldn't make much difference on a BAe 146 (or RJ n00).
Providing passengers with lifejackets is, IMO, one of the most worthless exercises in aviation.
On the Fokker 50, there are boards the CC are supposed to instal at the door sill level before opening them after a ditching. That always seemed to be to be a triumph of optimism over common sense.
I've never seen a case of an aircraft ditching successfully that didn't go down within a matter of minutes or less. So it wouldn't make much difference on a BAe 146 (or RJ n00).
Providing passengers with lifejackets is, IMO, one of the most worthless exercises in aviation.
The BAe146 is an interesting aircraft in several ways, but for ditching it is similar to many others. Some very early build 146 aircraft were not equipped with the ‘ditching mod’; actually all this meant was that the initial rear fuselage design strength did not meet the certification requirements, this was quickly rectified, but the structure changes not necessarily retrofitted. Aircraft without the mod will probably be restricted to operations within 85 nm of the shore i.a.w. other regulations.
I am not aware of the particular restriction quoted, but there may be different restrictions on which door to use between the different lengths of aircraft 100/200/300. Rear door restrictions are not uncommon for high wing aircraft; the wing does not play any part in the initial floating capability. Re Capt S post, the F50 uses ‘barge boards’ to dam fast water entry into the cabin via the rear doors.
Evacuation requirements are based on only a proportion of the doors being available; thus there is a case for inoperative doors in any MMEL. For ditching there may be a specific case in the 146 MMEL that considered the extent of the rear door restriction i.e. the floating water level is only 1 in above the door sill (does not meet the certification requirement), but for practical purposes and the extremely remote probability of ditching when operating with a rear door on the MEL it is perfectly acceptable and safe to operate in this manner for short period of time.
I am not aware of the particular restriction quoted, but there may be different restrictions on which door to use between the different lengths of aircraft 100/200/300. Rear door restrictions are not uncommon for high wing aircraft; the wing does not play any part in the initial floating capability. Re Capt S post, the F50 uses ‘barge boards’ to dam fast water entry into the cabin via the rear doors.
Evacuation requirements are based on only a proportion of the doors being available; thus there is a case for inoperative doors in any MMEL. For ditching there may be a specific case in the 146 MMEL that considered the extent of the rear door restriction i.e. the floating water level is only 1 in above the door sill (does not meet the certification requirement), but for practical purposes and the extremely remote probability of ditching when operating with a rear door on the MEL it is perfectly acceptable and safe to operate in this manner for short period of time.
"I've never seen a case of an aircraft ditching successfully that didn't go down within a matter of minutes or less." - I was on duty when the RAF Nimrod ditched just off the Morayshire coast (at Lossiemouth) many years ago, she stayed floating for quite a long time - 20 minutes or longer rings a bell (broken back and all) - maybe lucky but it can happen.
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maybe on the 146 it happens the same as for 737-400 for ditching. u would preferably avoid using the back doors because under one of the doors u can find the negative relief valve .
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Evacuation
Hi there
thanks for all the replies
but my point was that if you can only evacuate through the 2 forward doors then would this not limit the amount of people the aircraft could take in flights over water.
I know no 146 has gone down but if it were to then all the people from say the middle backwards would not have any real chance of getting off.
Also on bigger jets the evacuation slides can be turned into life rafts.....would the slides on the forward 146 doors be able to accomodate the full capacity of the aircraft since they are the only operational doors in this scenario??
Lastly i don't understand why all available doors are not allowed to be used.....if i were on the plane and i was seated at the back you can be sure im not going to wait for 80+ passengers to alight before me if i could jump out of the door beside me!!!
galleygirlapu forgive my ignorance but what does the negative relief valve have to do with getting off the plane on water since the rear doors are used on land.?
thanks for all the replies
but my point was that if you can only evacuate through the 2 forward doors then would this not limit the amount of people the aircraft could take in flights over water.
I know no 146 has gone down but if it were to then all the people from say the middle backwards would not have any real chance of getting off.
Also on bigger jets the evacuation slides can be turned into life rafts.....would the slides on the forward 146 doors be able to accomodate the full capacity of the aircraft since they are the only operational doors in this scenario??
Lastly i don't understand why all available doors are not allowed to be used.....if i were on the plane and i was seated at the back you can be sure im not going to wait for 80+ passengers to alight before me if i could jump out of the door beside me!!!
galleygirlapu forgive my ignorance but what does the negative relief valve have to do with getting off the plane on water since the rear doors are used on land.?
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You may find some information in the following report:
Analysis of Ditching and Water Survival Training Programs of Major Airframe Manufacturers and Airlines
Abstract: Current transport category aircrew training programs related to ditching and water survival are reviewed for content and attention to detail. This activity resulted from industry and regulatory inquiries about the state-of-the-art in ditching and water survival operations, especially with regard to the increasing number of aircraft operations, and associated opportunities for emergency water landing events, that the future will bring. The information on water landing events was gathered from published reports related to these issues. For example, Johnson (1984) cited 16 transport category water landings that occurred during the period from 1959 to 1979, and Chen and Muller (1994) reported that 33 water-impact accidents occurred in commuter-category aircraft from 1982 until 1989. An additional 21 water-related accidents or near accidents occurred in transport category aircraft from 1980 through 1994. Training materials related to ditching and water survival were provided by six major airframe manufacturers and nine major airlines. The purpose of the study was to examine the information flight attendants, as well as passengers, are provided about ditching and water survival equipment and procedures, to determine if existing training practices are satisfactory. Special emphasis is placed on unplanned water landing events. The resulting analysis identifies deficiencies in both water survival equipment and procedures, and recommends solutions designed to promote more advanced water landing and water survival operations.
Report Date: July 1998
Analysis of Ditching and Water Survival Training Programs of Major Airframe Manufacturers and Airlines
Abstract: Current transport category aircrew training programs related to ditching and water survival are reviewed for content and attention to detail. This activity resulted from industry and regulatory inquiries about the state-of-the-art in ditching and water survival operations, especially with regard to the increasing number of aircraft operations, and associated opportunities for emergency water landing events, that the future will bring. The information on water landing events was gathered from published reports related to these issues. For example, Johnson (1984) cited 16 transport category water landings that occurred during the period from 1959 to 1979, and Chen and Muller (1994) reported that 33 water-impact accidents occurred in commuter-category aircraft from 1982 until 1989. An additional 21 water-related accidents or near accidents occurred in transport category aircraft from 1980 through 1994. Training materials related to ditching and water survival were provided by six major airframe manufacturers and nine major airlines. The purpose of the study was to examine the information flight attendants, as well as passengers, are provided about ditching and water survival equipment and procedures, to determine if existing training practices are satisfactory. Special emphasis is placed on unplanned water landing events. The resulting analysis identifies deficiencies in both water survival equipment and procedures, and recommends solutions designed to promote more advanced water landing and water survival operations.
Report Date: July 1998
Pull up 3k, clarifying my earlier point; it is only the certification evacuation demonstration that uses a percentage of the doors and invokes a time constraint to evacuate all passengers on land.
In reality all available doors can be used and within whatever time scale is available. Thus for a 146 only using the forward doors there is every chance that all passengers will escape. (All pax are loaded and offloaded through one door, and very quickly after landing).
Some 146 are fitted with slide rafts – customer option, others carry additional rafts as required by national regulations.
The 146 / RJ series aircraft have a ‘dump/ditch’ flight deck control for the pressurization negative relief / discharge valves; selecting this mode closes the valves and prevents water ingress when ditching.
In reality all available doors can be used and within whatever time scale is available. Thus for a 146 only using the forward doors there is every chance that all passengers will escape. (All pax are loaded and offloaded through one door, and very quickly after landing).
Some 146 are fitted with slide rafts – customer option, others carry additional rafts as required by national regulations.
The 146 / RJ series aircraft have a ‘dump/ditch’ flight deck control for the pressurization negative relief / discharge valves; selecting this mode closes the valves and prevents water ingress when ditching.
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Just something else to add to the ditching subject. When this thing does stay afloat which is doubtful surely its going to roll off to one side . Im sure that there will either be a fuel, pax or someother inbalance or even a detatched engine. This then changes things as two doors on one side will be unserviceable for the particular situation.
I seem to recall that the 146 sits tail down in water (evidence mathematically modelled for Certification) and rolls to one side. Thus the forward doors are well above the water line and one of the rear doors has its threshold below. The seals around the submerged door should prevent significant water ingress, whilst the other rear door can also be opened to aid evacuation.
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Submarine??
Hi all,
The nimrod floating for 20 minutes does ring a bell. Was it not a submarine hunter?? It does seem we are speaking of submarines here.
Joking apart I guess things work out fine on paper yet, even though aircrews undergo training for ditching (to satisfy certain requirements by JAA, CAA or JAR or whoever) it is quite remote that aircraft remain afloat following ditching. First you would need the aircraft structure to remain intact on impact.
I would not really worry about RJ, as it not a long haul aircraft, so chances of flying for long periods of time over water (unlike nimrod... guess it even refuelled in flight) are very unlikely.
Wish you all a happy new year and definately no ditchings
The nimrod floating for 20 minutes does ring a bell. Was it not a submarine hunter?? It does seem we are speaking of submarines here.
Joking apart I guess things work out fine on paper yet, even though aircrews undergo training for ditching (to satisfy certain requirements by JAA, CAA or JAR or whoever) it is quite remote that aircraft remain afloat following ditching. First you would need the aircraft structure to remain intact on impact.
I would not really worry about RJ, as it not a long haul aircraft, so chances of flying for long periods of time over water (unlike nimrod... guess it even refuelled in flight) are very unlikely.
Wish you all a happy new year and definately no ditchings
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One of my treasured 'geek' possessions is a set of plans/project specs. for the Nimrod detailed then as the 'HS 801 Maritime Comet'. Much is made of the double hull design which is intended to keep the cabin afloat, stable and above water as long as possible 
Look at a Nimrod from head on, you'll see it easily
Look at a Nimrod from head on, you'll see it easily
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90 Second Rule
Pull Up,
Nobody has mentioned it, but I think there's a 90 Second Rule for evacuation (be it land or sea) as set out in airworthiness or legal or something..?
If this is the case, or even if that time varies depending on the size of aircraft, I'd argue that as many pasengers as can be evacuated in this time can be carried.
With regard to life-rafts, I'm not sure if they form a part of these constraints but passengers have life-jackets anyway.
I'd actually like to know more about legal constraints in designing for airworthiness (crashworthiness), although I'm sure I'll study it as part of my degree at some point - anybody got a link? or info??
Happy New Year
Andy
Nobody has mentioned it, but I think there's a 90 Second Rule for evacuation (be it land or sea) as set out in airworthiness or legal or something..?
If this is the case, or even if that time varies depending on the size of aircraft, I'd argue that as many pasengers as can be evacuated in this time can be carried.
With regard to life-rafts, I'm not sure if they form a part of these constraints but passengers have life-jackets anyway.
I'd actually like to know more about legal constraints in designing for airworthiness (crashworthiness), although I'm sure I'll study it as part of my degree at some point - anybody got a link? or info??
Happy New Year
Andy
Ditching
Avroliner, take care.
Even if you don’t fly your Avro RJ or BAe146 on long over water legs still think about the destination airfields. One slip at LCY , Genoa, etc. !!!
Structural integrity is important, but don’t think that you will get time for the ditching checks; remember the 737 that went off the end at LaGuardia.
The 146 ‘wheel to wingtip’ angle is about 18 deg. The aircraft is designed to float, and with the rear doors at water level the bank angle would be approx 10 deg, which includes half submerging one engine.
I referred to the evacuation requirements earlier; the 90 sec timing only applies to the certification test. The time does not vary with aircraft type, the number of passengers carried dictates the number of exits required in order to meet the time requirements.
Even if you don’t fly your Avro RJ or BAe146 on long over water legs still think about the destination airfields. One slip at LCY , Genoa, etc. !!!
Structural integrity is important, but don’t think that you will get time for the ditching checks; remember the 737 that went off the end at LaGuardia.
The 146 ‘wheel to wingtip’ angle is about 18 deg. The aircraft is designed to float, and with the rear doors at water level the bank angle would be approx 10 deg, which includes half submerging one engine.
I referred to the evacuation requirements earlier; the 90 sec timing only applies to the certification test. The time does not vary with aircraft type, the number of passengers carried dictates the number of exits required in order to meet the time requirements.
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pull up 3k,
The FAA maximum approved capacity for a BAe 146-100 is 94 passengers and for the -200/300 is 108 passengers. The -300 capacity is based on door flow rates confirmed during -200 certification. Those numbers are based on using only two of the four doors. The flow rate is 36 persons per minute through each door.
The BAe 146-100 floats tail down with one wing tip in the water, removing one door from the escape equation. This is established by using appropriate models. The larger -200 and -300 are less of a problem.
The FAA-approved slide raft fit, based on FAR 121 operating rules, limits the aircraft capacity to the overload capacity of two of the three available slide rafts. This allows for an unserviceability of one of the available slide rafts. In the case of the BAe 146-100/RJ 70, the limit is 68 for slide raft only configuration.
Other regulators have different rules.
Stay Alive.
The FAA maximum approved capacity for a BAe 146-100 is 94 passengers and for the -200/300 is 108 passengers. The -300 capacity is based on door flow rates confirmed during -200 certification. Those numbers are based on using only two of the four doors. The flow rate is 36 persons per minute through each door.
The BAe 146-100 floats tail down with one wing tip in the water, removing one door from the escape equation. This is established by using appropriate models. The larger -200 and -300 are less of a problem.
The FAA-approved slide raft fit, based on FAR 121 operating rules, limits the aircraft capacity to the overload capacity of two of the three available slide rafts. This allows for an unserviceability of one of the available slide rafts. In the case of the BAe 146-100/RJ 70, the limit is 68 for slide raft only configuration.
Other regulators have different rules.
Stay Alive.
