Disarming doors before ditching

[Rwy in Sight]

On Sunday, I managed to follow the pool training session of a European airline. The trainer stated that as part of the ditching preparation doors should be on the un-armed position (the type under consideration was the 733/4).

My question is why the door should be un-armed? My understanding from reading the safety card is that the door can be used as a flotation device. So it is useful to have the slide armed.

Is there something I don't see here?


Rwy in Sight

[ozangel]

In my experience, the reason we were given in training as to why in a ditching the doors should be put to manual/disarmed, is the door would more than likely (assuming the plane was level in the water) be below the water level, and the slide would ingest water and block the exit.

Our procedures were to use the overwing exits and chuck the life rafts out through them, before using the doors. The doors were supposed to be a last resort.

[christep]

It's a bit hypothetical since no-one has ever managed successfully to ditch an under-wing-engined passenger aircraft in open water.
(People got out of the Comoros one after it broke up on impact; where the doors/slides were wouldn't have made any significant difference, and the Indonesian one was more treating a shallow river as a wet runway rather than a ditching.)

[ditzyboy]

Answer is because some airlines will use liferafts from the primary exits on 737s. As these aircraft are not fitted with duel use 'sliderafts' (like A320, 747 etc) the slides are not used as they would get in the way of attaching and launching the rafts, which need to be brought to the door from overhead stowages.

[sixmilehighclub]

Inflatables float.
Slides are inflatable.
Open a door level with or below the waterline and the slide will float on the water as soon as it hit the water, ie, right by the door.
Inflating a slide at this water level pushes the slide either inwards to the cabin or upwards to the sky, blocking the exit.
Doors should only be opened in automatic if the door is above the waterline.

Your aircraft type and average aircraft weight (does your airline carry cargo, etc), will determine whther your policy is to have arms disarmed or armed in a ditching.

A B737 will usually use the overwing exits with the door slides as flotation devices only because the wings are higher than the doors and designed to float above water, also you can fit all passengers onto the wings. A B747 however has a higher centre of gravity for flotation and it is likely if the aircraft is in tact on ditching that majority of doors are above water. Sliderafts are used because the wings wouldnt accomodate all passengers and because it is more likely that you are further away from immediate assistance and may need to break or move away from the aircraft for survival.

The CAA in the UK for example, agree with the airline their policies and then publish that ruling/ agreement as an operating procedure and official drill for that airline.

However, with any emergency, you will use your instinct, skill and judgement on the day to maximise survival.

Check for hazards........etc

[blueloo]

As already mentioned in a variety of ways:

737s use slides and liferafts. Most liferafts are kept in dedicated overhead storage or overhead lockers.

Other airplanes use sliderafts.

The door can be opened armed, and then the slide detached, and if necessary used for floatation.

The procedure is not to, because as some have mentioned it may block the door (possible, but unlikely), most slides/slide rafts use air aspirators to inflate (not sure if 737 slide does) and water ingestion will pump water inside the slide if the aspirators are submerged, it is not designed for survival at sea, its not very big and probably wouldnt be able to remain stable/upright with more than a couple of people on it.

The dedicated raft has sea anchors, some survival gear, stability, a cover for shelter, and some alerting gear, the slide has none of these.

[flybywire]

The 737 is a funny aircraft. I love working on it, but it is indeed a funny one.:}

It is not as high as other SH aircraft (like the A320 family for example), was made like that to be "easier" to turn around and for other technical reasons. If you look at it you can see that its engines had to be "onion-shaped" (flat at the bottom) because it sits so close to the ground.(series -300/400/500 and NG)

It has been noticed than in a ditching it is likely that the water level would be above the door sill hence making these exits unusable for two reasons:

1) the slide has to drop a certain height before it can successfully deploy
(I once witnessed an armed door being accidentally opened and since the stairs were in place the bustle opened up but thank god the slide didn't have far to go as it just fell onto the top of the stairs, and there it rested till engineers could make the door serviceable again)

2) On ANY aircraft, if you open a door when the water level is not safe (for example because of the attitude of the aircraft) it is a big problem as the last thing you want is to have water come inside the aircraft when you're trying to get out!

That's why most 737 Operators's Ditching procedures require the crew to disengage the slides and brief the passengers accordingly as part of the cabin preparations and re-direct passengers to the OW exits. That's where they/we would stay till the rescue services arrive.

To clarify most operator's 737 slides are slides/flotation devices and not slide/rafts i.e. the slide can be detatched and used as a flotation aid but can't cope with big weights for long periods of time (pax cannot board it and use it as shelter like the slide/raft). BA doesn't have any life rafts (those stored in the ceiling or OH lockers as blueloo has explained) on board either as we don't have flights where we cross big waters, but I am pretty sure that other airlines have them. Believe it or not the 737 was the very first ETOPS aircraft!!! :rolleyes:

So....that's what we should do in a planned ditching. On the other hand in an unplanned ditching it's up to you and the specific situation and what you can actually do on the day....I personally think I'd meditate on converting to some powerful religion and start praying really hard!!! ;););)

FBWxxx

[Rwy in Sight]

Thanks a lot for your answers.

However the instruction described the slide as a flotation device. The follow up question then is how do you put it in the water to be used as such? At the end of the session they put the raft in the pool and practice (if I understand well) to take hold from the raft.

By the way the slide the did blow had an aspirator.


Rwy in Sight

PS It was a lovely Sunday only if they let me dive in the pool having put on a life jacket!

[flybywire]

well ideally you'd be able to open the door, deploy the slide and then detatch it by pulling a grey handle that is underneath a flap. Slides as you said are only floatation devices and not slide/rafts, so they would help but are not "essential" (if you can use this word in a ditching!).

However even if the water line were below the door sill, the priority would still be to get the pax on the wings and ask them to sit closely together (one behind the other) to maximise the space and keep their body warmth. Unless "absolutely necessary" (for example if the plane starts to sink) pocedures advise us to keep them as "dry" as practically possible while waiting to be rescued. If the doors can be used then we would engage the girt bar, open the door, inflate the slide/flotation device and then separate it and use it but, as I said before, the OW exits would still remain our primary escape route. We do need to know how to use the slides hence the need of a practical training in a swimming pool. (great fun, I remember!)

I know it can all sound a bit confusing and way too minimalist, but let's remember that the 737 is a short-haul aircraft with an autonomy of <5 hours on full load (I'm thinking of the 400 at the moment) and that is rarely used on transatlantic routes. Those airlines that do use them on such routes have special equipment on board (like some BBJ for example) and very rarely carry 180 people!!!!!
As I said before given the routes operated by this aircraft Ideally the rescue services would reach the poor old 737 quicker than if it happened to a 777 in the middle of the ocean!!

Though the hard work is to make sure it will never happen!! ;) :ok:

FBW:E

[6chimes]

Just to add to the information already given here.

The 737 is tail heavy and the rear doors would definately be submerged in a ditching. However the forward doors should be above the water line and you could use the slides as floatation aids. (assuming that you ditch on a perfect day where the water is as flat as a millpond!), Thats the SEP from my company anyway.

6

[muschixxl]

well ideally you'd be able to open the door, deploy the slide and then detatch it by pulling a grey handle that is underneath a flap. Slides as you said are only floatation devices and not slide/rafts, so they would help but are not "essential" (if you can use this word in a ditching!).

However even if the water line were below the door sill, the priority would still be to get the pax on the wings and ask them to sit closely together (one behind the other) to maximise the space and keep their body warmth. Unless "absolutely necessary" (for example if the plane starts to sink) pocedures advise us to keep them as "dry" as practically possible while waiting to be rescued. If the doors can be used then we would engage the girt bar, open the door, inflate the slide/flotation device and then separate it and use it but, as I said before, the OW exits would still remain our primary escape route. We do need to know how to use the slides hence the need of a practical training in a swimming pool. (great fun, I remember!)

I know it can all sound a bit confusing and way too minimalist, but let's remember that the 737 is a short-haul aircraft with an autonomy of <5 hours on full load (I'm thinking of the 400 at the moment) and that is rarely used on transatlantic routes. Those airlines that do use them on such routes have special equipment on board (like some BBJ for example) and very rarely carry 180 people!!!!!
As I said before given the routes operated by this aircraft Ideally the rescue services would reach the poor old 737 quicker than if it happened to a 777 in the middle of the ocean!!

Though the hard work is to make sure it will never happen!! ;) :ok:

FBW:D :D I totally agree with flybywire and I wished I would have always such professional cabin crew members in my team!!!!!

[blueloo]

The latter model, or larger varient 737s are tail heavy - ie 737-800s. THe rear doors are likely to be obstructed by water, and hence are not a primary means of escape in a ditching, and whilst the 733/4s more than likely to be tail heavy too, the rear doors on these models are a primary means of escape in a ditching.

[sixmilehighclub]

the instruction described the slide as a flotation device. The follow up question then is how do you put it in the water to be used as such?

Re-enter the aircraft is safe to do so, arm door and open door to blow slide. Detatch slide and using lifejackets float in water hanging onto th grabhandles around the edge of the slide. The slide should not be boarded, however if you have a casualty in the water it can be used for them to lie on, used to make CPR easier, etc and if in an unplanned ditching and no lifecot was available, you can use it to float the baby out of the water.
The slide can be detatched for use as flotation on a B737 if the door is in manual and approached from the outside. Remove bustle cover move to one side and pull manual inflation handle, or grab the assistance of someone, float either side of the door and pull the girtbar down into the water. Just ensure everyone is clear of the area and on the wings first.

whilst the 733/4s more than likely to be tail heavy too, the rear doors on these models are a primary means of escape in a ditching. That depends on the company SOP's.
Majority of airlines suggest overwing exits on a B737-xxx are primary evacuation or escape routes. I'm trying to think of one that doesnt....

On such a small aircraft, everyone moving down the ailse for the slides down at the back doors may make your aircraft tail heavy!! The wings are the centre of gravity on water on a B737.

Basic rule of thumb, if you have slideRAFTS attached to a door, it should be suitable for initial exit in a ditching (hazards permitting). If its not a raft, its designed not to be sat on, therefore designed not to have people leaving the aircraft on it. However if your SOPs say differently, stick with that as it would have been approved for your airline and tailored for the type of aircraft you have and the average weight distribution and trim for your daily operation.

Six:ok:

[Muttley Crew]

as part of the ditching preparation doors should be on the un-armed position (the type under consideration was the 733/4).

My question is why the door should be un-armed? My understanding from reading the safety card is that the door can be used as a flotation device

How can you use a door as a floatation device?

The 737 is thought to sit tail-down in water, according to Boeing manuals. Would be a shame to open the rear doors and sink the thing even faster.

The door slide on the 737 is NOT a raft. You have to get the rafts out of the over-head lockers during the panic and mayhem as fat people are trying to save themselves.

[flybywire]

Sixmile....I totally agree and thank you!!! You just saved me a very long reply :ok:

MuttleyCrew...I am sure RWYinSight meant "door slide" and not "door" only :) and you're indeed correct, the 737 slide is only a flotation device and not a slide/raft. the 737 doors are small and the slide bustle way too tiny for a proper (and big enough) raft to be installed in it.

Muschixxl thank you for your compliment :8 I worked on so many different types of aircraft but each time I really made a point to try and know it as much as possible, as at the end of the day that's where I spend most of my time...the aircraft soon feels like it's Home (although much dirtier and smellier) :E ;)

FBW x

[WHBM]

It's a bit hypothetical since no-one has ever managed successfully to ditch an under-wing-engined passenger aircraft in open water.
Not so. Japan Air Lines put a DC-8 into San Francisco Bay about 2 miles before the runway when on final approach in poor (I presume !) visibility. I believe they used the rafts in a fully textbook manner. Amazingly the aircraft was recovered, fully overhauled and flew again. There used to be a picture on airliners.net of it being recovered by barge to the United maintenance base at SFO alongside the bay but it has gone.

The Comores accident was unfortunate because just as they were on final approach to the ditching at minimum speed one engine failed with fuel starvation and they got the wing down ditching seen on videos taken from the beach.

Although there is a perception of ditching being a mid-ocean thing the vast majority which have happened seem to have been very close to shore.

[6chimes]

The Comores accident was unfortunate because just as they were on final approach to the ditching at minimum speed one engine failed with fuel starvation and they got the wing down ditching seen on videos taken from the beach.


I love the way a incident brings about many different version of events! I was always told the reason the wings dipped was partially due to the captain being hit over the head with a hammer as it was a hijacked a/c....maybe its a different ditching! Hope your version is correct, mine is quite horrible.

The latter model, or larger varient 737s are tail heavy - ie 737-800s. THe rear doors are likely to be obstructed by water,

I was given that info long before the 737 800 was introduced.

6

[flybywire]

Not so. Japan Air Lines put a DC-8 into San Francisco Bay about 2 miles before the runway when on final approach in poor (I presume !) visibility. I believe they used the rafts in a fully textbook manner. Amazingly the aircraft was recovered, fully overhauled and flew again. There used to be a picture on airliners.net of it being recovered by barge to the United maintenance base at SFO alongside the bay but it has gone.
The Comores accident was unfortunate because just as they were on final approach to the ditching at minimum speed one engine failed with fuel starvation and they got the wing down ditching seen on videos taken from the beach.
Although there is a perception of ditching being a mid-ocean thing the vast majority which have happened seem to have been very close to shore.

True and correct :ok:

The 1996 Comores accident was the one that involved an Ethiopian 767-200 flying from Addis Ababa to Nairobi. There were people on the beach who filmed the attempted ditching as it only happened some 500m from the sea shore! There were about 200 people on board including the crew and at least 2/3 of them didn't survive. I remember watching the video during my very first initial CRM course and you could clearly spot rows of seats being thrown out of the aircraft into the air....it was very scaring and one person resigned straight after seeing it (oh dear!:rolleyes: )
All in all that ditching was a "success" as some 50 odd people survived it, and as WHBM said the hijacked aircraft was running out of fuel so I think the pilots did a very good job given the circumstances.

I never heard the version of the captain being hit on the head on landing... though from now on I'll have to do some proper investigation every time we get a bit of an "arrival"... ;) :E

FBW:)

PS: 6chimes you are correct I have had a look in the 737-300/400/500 systems manual and they are too tail-heavy.

[angels]

An acquaintance of mine died on the Ethiopian flight so it's something I've looked quite closely into.

I've never heard the hammer story.

[Lord Snot]

The Ethiopian was being beaten with a fire extinguisher. A subtle difference...

The hammer tale took place on a freighter in the USA where a staff member took to the 3 crew-members with a claw-hammer.

[sixmilehighclub]

The version I was led to believe....

On the first diversion demand, the pilots changed heading but on approach discovered they couldn't land there.

When the second diversion destination was demanded by the hijackers, the pilots pointed out they didnt have enough fuel to get there, the hijackers forced them to continue, and eventually the aircraft went in to ditch.

The Hijackers were convinced by now that the pilots were trying to trick them and one grabbed the controls as the aircraft was imminently ditching, just feet above the water. As a result, one wingtip hit the water first and was torn off, sending the aircraft into the water at a catastrophic angle.

Experts say ifit hadnt been caused to list, it looked like it would have been a succesful ditching.

[chadwick]

Question - how many successful ditchings have cause all passenger to actually be able to exit the aircraft in the manner describe. Be realistic folks, the flight deck have to have a flat calm mill pond to land without loosing engines and clipping wings to get the a/c hull to land in one piece and deploy the shoots! Experts say ifit hadnt been caused to list, it looked like it would have been a succesful ditching.One has ones doubts about that, read the official report.

The reason for the suggestion it would be successful was shallow water but realistically
you are not going to be over those conditions in a normal situation.:rolleyes:

Your training is there to make you feel comfortable in the situation and not alot more!

[skytrax]

The procedures for ditching are diffrent from an a/c to another.
I don't fly 737, but I do fly B777, A330, 340, mostly long and ultra long haul. The rule is that if the door has a slideraft u keep it armed and u open it, as the slideraft cand be detached from the a/c and used a raft. If the door has just a slide, the drill says to disarm, block the doors and redirect the pax.
However, if the situation is catastrophic and you cannot open other doors, you open, for example, LR3 doors in 777 to evacuate. If u have to get "t.. h.." out of there you have to use any possible way.

[blueloo]

There are a couple of thoughts with that 767 ditching accident.

1 - the captain was clobbered in the head with the crash axe
2- the 767 with dual engine flameout (due to fuel starvation in this case), has a RAT (Ram Air Turbine) which drops out to provide hydraulic power to the primary flight controls. To maintain sufficent hydraulic power there is a mimimum airspeed that has to be maintained ( I cant remember what that is). There was the possibility that combined with a wack to the head, and the hijackers on the flight deck with the struggle, that the airspeed dropped below the minimum, causing a wing drop.

[flybywire]

Question - how many successful ditchings have cause all passenger to actually be able to exit the aircraft in the manner describe. Be realistic folks, the flight deck have to have a flat calm mill pond to land without loosing engines and clipping wings to get the a/c hull to land in one piece and deploy the shoots! One has ones doubts about that, read the official report.

The reason for the suggestion it would be successful was shallow water but realistically
you are not going to be over those conditions in a normal situation.:rolleyes:

Your training is there to make you feel comfortable in the situation and not alot more!



Definitely agree. that's why nobody would like to be in that situation and why ditching in whatever aircraft you are is really just the last resort when the other option would just be to kiss your rear goodbye!!!!!!!

I don' know (and don't want to try it either) whether it would work out this way, but boeing have created these guidelines for the possible attitude of the a/c in "a pond" so I believe that if the situation was much worse almost definitely the rear doors would be impossible to operate anyway.

I said it, the 737 is a funny aircraft, but very unlikely flies at a distance from the continent that would make you consider not being able to reach an airport during an emergency. Unless it's something clearly catastrophic and then it would be a good time to do some serious praying ;)

FBW

[Simwings]

Going back to the EA762 Incident;

It was pretty successful given what was going on, though it could have gone better had the wings been level on landing, because when it hit the water, one of the wing-tips turned the a/c around.

Now that much Aircraft, doing a 360 at that speed, in such a short turning circle meant the ac broke up far more easily than it would have done, had just the engines touched the water and scooped up the water.

Although, like I said, I've not idea what was happening on the flight deck for the pilot to have turned the plane like that - one of the terrorists could have been up to no good, etc.

Though even more passengers than this could have survived, had it been made more clear to them that they shouldn't have inflated their life jackets until outside the a/c - it's vital the pax know just how important that is.

[Rwy in Sight]

Regarding inflating the jackets. One of the things PPRuNe taught me is to watch the demostration of safety equipment.

One of the local airlines say nothing about when to inflate the jackets the other say "inflate as you leave the aircraft". It seems the first mentions about jackets inflation on the pre-ditching briefing.

My visit at the pool was useful for me because I have not realise the meaning of inflate the jacket as you leave the a/c. I thought it was ok to inflate once you were on the water but now I understand and have a visual on the notion of pulling the tabs as you step out of the sill.


Rwy in Sight