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convair880mfan
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Since LAX departures are usually out over the ocean, do all aircraft need overwater equipment?

Mon Sep 27, 2021 5:31 am

Most LAX departures fly out a ways over the Pacific Ocean before turning. Do all the airliners that fly into or out of LAX need rafts and life vests? A lot of different type aircraft utilize this airport including smaller regional jets and turboprop airliners. What are the rules? I realize that many aircraft do not fly very far over the water before making various standard turns towards land.

Someone told me that water safety equipment isn't required unless a plane flies 50 miles from shore. Even if I was just 10 or 20 miles from shore and a plane had to ditch in the ocean I would like to have a life vest and a raft of some kind.
 
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Starlionblue
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Re: Since LAX departures are usually out over the ocean, do all aircraft need overwater equipment?

Mon Sep 27, 2021 6:56 am

convair880mfan wrote:
Most LAX departures fly out a ways over the Pacific Ocean before turning. Do all the airliners that fly into or out of LAX need rafts and life vests? A lot of different type aircraft utilize this airport including smaller regional jets and turboprop airliners. What are the rules? I realize that many aircraft do not fly very far over the water before making various standard turns towards land.

Someone told me that water safety equipment isn't required unless a plane flies 50 miles from shore. Even if I was just 10 or 20 miles from shore and a plane had to ditch in the ocean I would like to have a life vest and a raft of some kind.


Not all aircraft would need it, as there is no need for overwater equipment unless you're going to be a certain distance from shore. Twenty miles is not very far in an airliner. Even If you lost all engines a few minutes after departure, you could glide to land. As a rule of thumb, for every thousand feet of altitude, you can glide at least three or four nautical miles.

If there are no life vests, the seat cushions are floatation devices.
 
mxaxai
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Re: Since LAX departures are usually out over the ocean, do all aircraft need overwater equipment?

Mon Sep 27, 2021 10:30 am

Starlionblue wrote:
If there are no life vests, the seat cushions are floatation devices.

I was under the impression that all part 121 operations need an approved floatation device unless granted an explicit exception. So on modern slimline economy seats that should require life vests.
 
Woodreau
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Re: Since LAX departures are usually out over the ocean, do all aircraft need overwater equipment?

Mon Sep 27, 2021 10:51 am

Under FAR 121 rules, aircraft that are not overwater equipped cannot fly further than 50nm from land. Most regional jets in the US operated by regional airlines are not overwater equipped (I.e. no liferafts and life jackets onboard.). There should be a placard at each seat stating the seat cushion can be used as a flotation device in the event of a water landing.

Since there is no seat cushion on a slimline seat, aircraft with those seats are very likely to be overwater equipped so there are rafts and life jackets onboard.

You’ll be able to tell if an aircraft is overwater equipped or not by looking in the safety briefing card. It won’t say in words, but the graphics will indicate whether you are able to don a life jacket or if you have to pull the seat bottom off the seat and hug it in the water.
 
convair880mfan
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Re: Since LAX departures are usually out over the ocean, do all aircraft need overwater equipment?

Mon Sep 27, 2021 3:16 pm

If an airliner took off from LAX and had to ditch in the Pacific Ocean for whatever reason . . . and some souls were lost, I'll bet there would be some change in FAR 121 rules. If often takes a disaster for rules to change. Personally speaking, I wouldn't like to be in who knows how cold of ocean water with my feet dangling down and clutching a seat cushion . . . especially if those were shark infested waters.

By the way . . . on long overwater operations where there are life rafts . . . are there enough to accommodate a full passenger load and crew complement?
 
GalaxyFlyer
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Re: Since LAX departures are usually out over the ocean, do all aircraft need overwater equipment?

Mon Sep 27, 2021 3:36 pm

Risk analysis is about likely risks and accounting for them, not about creating zero risk.

To your second comment, yes with 50% over capacity, that’s not 50% more rafts. It’s the rafts have the flotation of carrying 50% more load than designed capacity. An 8 person raft can float 12 persons.
 
GalaxyFlyer
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Re: Since LAX departures are usually out over the ocean, do all aircraft need overwater equipment?

Mon Sep 27, 2021 3:39 pm

GalaxyFlyer wrote:
Risk analysis is about likely risks and accounting for them, not about creating zero risk. Take-off performance is not based on all engines failing.

To your second comment, yes with 50% over capacity, that’s not 50% more rafts. It’s the rafts have the flotation of carrying 50% more load than designed capacity. An 8 person raft can float 12 persons.
 
N1120A
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Re: Since LAX departures are usually out over the ocean, do all aircraft need overwater equipment?

Mon Sep 27, 2021 6:10 pm

The chance of a water ditching on any departure out of LAX is so slim that it may as well be none. The SIDs that take aircraft further out are reserved for jet engined aircraft that are highly unlikely to have any engine failure, let alone multiple engine failures. The ones used for light airplanes generally keep people close to shore. Incidentally, the geography of that part of the California coast means that even straight out departures from LAX get you closer and closer to shore as you get further out, especially if you depart the north complex, and south complex departures mostly turn southeast.

In other words, it is a non issue. If you were unlucky enough to need to ditch, you're helped by the fact that you are 1) right off shore from one of the busiest, best equipped airports in the world, 2) near the one of world's busiest ports, 3) near a whole bunch of Coast Guard assets.
 
convair880mfan
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Re: Since LAX departures are usually out over the ocean, do all aircraft need overwater equipment?

Mon Sep 27, 2021 6:18 pm

I definitely agree with that.

I also think there is a "human factor" in this for better or worse. Airlines are in business to make money for their stockholders. Passengers will pay or will not pay for certain risk probabilities. All things being equal and human beings being completely logical would simplify this. But all things are not always equal and people do act illogically even with their travel spending.

The Boeing 737 Max is an example. A pilot in the US told me that turning off the electric motors driving trim motors can prevent the kind of 737 Max accidents of recent history. He said there was no reason to ground those planes. No US carrier using the 737 Max suffered the same fate as the two carriers that had accidents. But the planes were still grounded and Boeing was required to make them "safer." Now maybe that pilot is completely wrong, but if he were right, then logic alone does not always dictate outcomes.

Perfect safety is impossible by definition but the question is, how much money is a passenger willing to pay for a ticket for added safety and I think a lot of passengers choose flights based on the cheapest tickets. If people became averse to twin engine jetliners and averse enough to not fly, trijets would come back. But I would imagine it would take a lot of twin jet losses in a short span of time for that to happen and perhaps even then money considerations would trump safety.

A whole lot of things changed after 9/11 because some young people with box cutters did unbelievably horrific things. TSA was created. One couldn't go to an in airport viewing area unless one had a plane ticket and so on. People put up with all this to feel safe. Who am I to question this?

An airline could make more money per flight with aircraft with one engine and one pilot, but who would go on such flights? Airline companies sometimes go out on a limb to save money and then wait and see how the FAA or other countries aviation authorities are going to rule or vice versa. Using forklifts to remove DC-10 engines, for example. ETOPS was unthinkable at some time and then it wasn't.

Luckily in most cases, saner minds prevail. If x event is very highly improbable and the cost of making it even more improbable is something the airline public wouldn't pay for in higher ticket costs, then what airline is going to pass on those costs to their stock holders?

I ride Amtrak a lot and there are no seatbelts. Some poor souls lost their lives this week in an Amtrak derailment. Will seatbelts come to trains or not?

And its not just safety that is often ruled by the bottom line. Look how many seats they keep cramming into airliner cabins. There are even concept "standing seats" in the works. Yikes.
 
N1120A
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Re: Since LAX departures are usually out over the ocean, do all aircraft need overwater equipment?

Tue Sep 28, 2021 5:07 pm

You assume seat belts would save more lives on Amtrak. The most dangerous train accidents are ones where evacuation is what will save you, not being stationary. Similarly, you assume airplanes operate in a bubble. Vests and rafts aren't what you are going to need on the sort of highly unlikely catastrophic ditching from LAX.
 
kalvado
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Re: Since LAX departures are usually out over the ocean, do all aircraft need overwater equipment?

Tue Sep 28, 2021 6:51 pm

N1120A wrote:
The chance of a water ditching on any departure out of LAX is so slim that it may as well be none. The SIDs that take aircraft further out are reserved for jet engined aircraft that are highly unlikely to have any engine failure, let alone multiple engine failures. The ones used for light airplanes generally keep people close to shore. Incidentally, the geography of that part of the California coast means that even straight out departures from LAX get you closer and closer to shore as you get further out, especially if you depart the north complex, and south complex departures mostly turn southeast.

In other words, it is a non issue. If you were unlucky enough to need to ditch, you're helped by the fact that you are 1) right off shore from one of the busiest, best equipped airports in the world, 2) near the one of world's busiest ports, 3) near a whole bunch of Coast Guard assets.

If that is of any example, US1549 was a jet which suddenly lost both engines shortly after takeoff.
It didn't have to be overwater equipped for that flight, flight plan was overland.
But the plane was overwater rated nonetheless.
But nobody actually went swimming after the ditch with that overwater equipment as everyone was taken off pretty quickly.
But that rescue had nothing to do with being right off shore from one of the busiest, best equipped airports in the world ( total of 3 of them), nor being near a whole bunch of Coast Guard assets.
 
N1120A
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Re: Since LAX departures are usually out over the ocean, do all aircraft need overwater equipment?

Tue Sep 28, 2021 7:14 pm

kalvado wrote:
N1120A wrote:
The chance of a water ditching on any departure out of LAX is so slim that it may as well be none. The SIDs that take aircraft further out are reserved for jet engined aircraft that are highly unlikely to have any engine failure, let alone multiple engine failures. The ones used for light airplanes generally keep people close to shore. Incidentally, the geography of that part of the California coast means that even straight out departures from LAX get you closer and closer to shore as you get further out, especially if you depart the north complex, and south complex departures mostly turn southeast.

In other words, it is a non issue. If you were unlucky enough to need to ditch, you're helped by the fact that you are 1) right off shore from one of the busiest, best equipped airports in the world, 2) near the one of world's busiest ports, 3) near a whole bunch of Coast Guard assets.

If that is of any example, US1549 was a jet which suddenly lost both engines shortly after takeoff.
It didn't have to be overwater equipped for that flight, flight plan was overland.
But the plane was overwater rated nonetheless.
But nobody actually went swimming after the ditch with that overwater equipment as everyone was taken off pretty quickly.
But that rescue had nothing to do with being right off shore from one of the busiest, best equipped airports in the world ( total of 3 of them), nor being near a whole bunch of Coast Guard assets.


Actually, the quick rescue in that situation had everything to do with being close to tons of maritime assets in the Hudson. If the passengers had gotten in the water, their fate may have been more cloudy, given how cold it was.
 
kalvado
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Re: Since LAX departures are usually out over the ocean, do all aircraft need overwater equipment?

Tue Sep 28, 2021 7:20 pm

N1120A wrote:
kalvado wrote:
N1120A wrote:
The chance of a water ditching on any departure out of LAX is so slim that it may as well be none. The SIDs that take aircraft further out are reserved for jet engined aircraft that are highly unlikely to have any engine failure, let alone multiple engine failures. The ones used for light airplanes generally keep people close to shore. Incidentally, the geography of that part of the California coast means that even straight out departures from LAX get you closer and closer to shore as you get further out, especially if you depart the north complex, and south complex departures mostly turn southeast.

In other words, it is a non issue. If you were unlucky enough to need to ditch, you're helped by the fact that you are 1) right off shore from one of the busiest, best equipped airports in the world, 2) near the one of world's busiest ports, 3) near a whole bunch of Coast Guard assets.

If that is of any example, US1549 was a jet which suddenly lost both engines shortly after takeoff.
It didn't have to be overwater equipped for that flight, flight plan was overland.
But the plane was overwater rated nonetheless.
But nobody actually went swimming after the ditch with that overwater equipment as everyone was taken off pretty quickly.
But that rescue had nothing to do with being right off shore from one of the busiest, best equipped airports in the world ( total of 3 of them), nor being near a whole bunch of Coast Guard assets.


Actually, the quick rescue in that situation had everything to do with being close to tons of maritime assets in the Hudson. If the passengers had gotten in the water, their fate may have been more cloudy, given how cold it was.

That's why I conveniently omitted "near major port" from the comment :) I doubt airports have a lot of boats on property or crews to operate them, though.
Reading up on event, slides were used as rafts - so overwater equipment was actually used; and at least one person went into the water to swim to rescue boat. Coast guard was promptly on the scene as well - although bulk (all?) of people rescue was done by others.
 
N1120A
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Re: Since LAX departures are usually out over the ocean, do all aircraft need overwater equipment?

Wed Sep 29, 2021 2:50 pm

kalvado wrote:
N1120A wrote:
kalvado wrote:
If that is of any example, US1549 was a jet which suddenly lost both engines shortly after takeoff.
It didn't have to be overwater equipped for that flight, flight plan was overland.
But the plane was overwater rated nonetheless.
But nobody actually went swimming after the ditch with that overwater equipment as everyone was taken off pretty quickly.
But that rescue had nothing to do with being right off shore from one of the busiest, best equipped airports in the world ( total of 3 of them), nor being near a whole bunch of Coast Guard assets.


Actually, the quick rescue in that situation had everything to do with being close to tons of maritime assets in the Hudson. If the passengers had gotten in the water, their fate may have been more cloudy, given how cold it was.

That's why I conveniently omitted "near major port" from the comment :) I doubt airports have a lot of boats on property or crews to operate them, though.
Reading up on event, slides were used as rafts - so overwater equipment was actually used; and at least one person went into the water to swim to rescue boat. Coast guard was promptly on the scene as well - although bulk (all?) of people rescue was done by others.


Most of the passengers and crew stood on the wings and were rescued by local boat traffic in the Hudson. In that situation, it was actually better that they didn't get into the water, as hypothermia was a real risk.
 
Okcflyer
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Re: Since LAX departures are usually out over the ocean, do all aircraft need overwater equipment?

Wed Sep 29, 2021 4:04 pm

N1120A wrote:
kalvado wrote:
N1120A wrote:

Actually, the quick rescue in that situation had everything to do with being close to tons of maritime assets in the Hudson. If the passengers had gotten in the water, their fate may have been more cloudy, given how cold it was.

That's why I conveniently omitted "near major port" from the comment :) I doubt airports have a lot of boats on property or crews to operate them, though.
Reading up on event, slides were used as rafts - so overwater equipment was actually used; and at least one person went into the water to swim to rescue boat. Coast guard was promptly on the scene as well - although bulk (all?) of people rescue was done by others.


Most of the passengers and crew stood on the wings and were rescued by local boat traffic in the Hudson. In that situation, it was actually better that they didn't get into the water, as hypothermia was a real risk.


While the Hudson isn't exactly the most "clam" body of water, the Pacific Ocean is a whole other animal. Had Sully landed 1549 in the Pacific, it's very unlikely it would have stayed together as one piece and had the same heroic outcome.

Likewise, had that incident happened in another large metro area, the outcome likely would have been even more catastrophic than a hypothetical ditching in the Pacific as it's improbable they would have been able to find enough open space to sit her down without crashing into buildings or other ground items (Think TACA 110 and magically finding a suitable levy). These are not Cessna's and highways/roadways aren't going to work very well.

I am a bit curious as to how the regulations assume an ocean ditching would work. I assume they expect it to occur as a gradual descent from cruise with enough time to prepare the cabin,doning life vests, and possibly including fetching the life rafts from storage and getting them next to a door? It's likely that most aircraft will break up in some fashion while "landing". If this is the case, it'll be difficult to get the life rafts out once crashed. The slides are easy since they automatically inflate also serve as floatation.

In the case of LAX, the most critical period would be double engine failure immediately after take off, long before reaching the 50nm mark. It's extremely unlikely both engines fail at the same time. If one fails and you're heading away from shore, one of the higher priorities tasks should be a turn to either parallel or back to shore just in case a problem develops with the other.

The recent 737 freighter ditching in Hawaii kept flying away from land on one engine instead of going parallel with, or back to incase further problems developed.
Last edited by Okcflyer on Wed Sep 29, 2021 4:12 pm, edited 1 time in total.
 
kalvado
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Re: Since LAX departures are usually out over the ocean, do all aircraft need overwater equipment?

Wed Sep 29, 2021 4:10 pm

N1120A wrote:
kalvado wrote:
N1120A wrote:

Actually, the quick rescue in that situation had everything to do with being close to tons of maritime assets in the Hudson. If the passengers had gotten in the water, their fate may have been more cloudy, given how cold it was.

That's why I conveniently omitted "near major port" from the comment :) I doubt airports have a lot of boats on property or crews to operate them, though.
Reading up on event, slides were used as rafts - so overwater equipment was actually used; and at least one person went into the water to swim to rescue boat. Coast guard was promptly on the scene as well - although bulk (all?) of people rescue was done by others.


Most of the passengers and crew stood on the wings and were rescued by local boat traffic in the Hudson. In that situation, it was actually better that they didn't get into the water, as hypothermia was a real risk.


Just looking at the picture:
https://bloximages.newyork1.vip.townnew ... .image.jpg
https://www.aviation-accidents.net/wp-c ... US1549.jpg
I can count some 30 people on each wing, give or take. Maybe 5-7 people on the 1L and 1R slides. That is 70 out of 155 souls on board.
There is also something about Sully asking arriving boats to pick up for those on wings first as he deemed those on rafts to be relatively safe.
And, quoting wiki, "One passenger, after helping with the evacuation, found the wing so crowded that he jumped into the river and swam to a boat."
Had to be really crowded!
 
GalaxyFlyer
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Re: Since LAX departures are usually out over the ocean, do all aircraft need overwater equipment?

Wed Sep 29, 2021 6:25 pm

Okcflyer wrote:
N1120A wrote:
kalvado wrote:
That's why I conveniently omitted "near major port" from the comment :) I doubt airports have a lot of boats on property or crews to operate them, though.
Reading up on event, slides were used as rafts - so overwater equipment was actually used; and at least one person went into the water to swim to rescue boat. Coast guard was promptly on the scene as well - although bulk (all?) of people rescue was done by others.


Most of the passengers and crew stood on the wings and were rescued by local boat traffic in the Hudson. In that situation, it was actually better that they didn't get into the water, as hypothermia was a real risk.


While the Hudson isn't exactly the most "clam" body of water, the Pacific Ocean is a whole other animal. Had Sully landed 1549 in the Pacific, it's very unlikely it would have stayed together as one piece and had the same heroic outcome.

Likewise, had that incident happened in another large metro area, the outcome likely would have been even more catastrophic than a hypothetical ditching in the Pacific as it's improbable they would have been able to find enough open space to sit her down without crashing into buildings or other ground items (Think TACA 110 and magically finding a suitable levy). These are not Cessna's and highways/roadways aren't going to work very well.

I am a bit curious as to how the regulations assume an ocean ditching would work. I assume they expect it to occur as a gradual descent from cruise with enough time to prepare the cabin,doning life vests, and possibly including fetching the life rafts from storage and getting them next to a door? It's likely that most aircraft will break up in some fashion while "landing". If this is the case, it'll be difficult to get the life rafts out once crashed. The slides are easy since they automatically inflate also serve as floatation.

In the case of LAX, the most critical period would be double engine failure immediately after take off, long before reaching the 50nm mark. It's extremely unlikely both engines fail at the same time. If one fails and you're heading away from shore, one of the higher priorities tasks should be a turn to either parallel or back to shore just in case a problem develops with the other.

The recent 737 freighter ditching in Hawaii kept flying away from land on one engine instead of going parallel with, or back to incase further problems developed.


Ditching cannot be tested during certification, so the engineering uses models, prior events and assumptions to certify. The NTSB and EASA, during the investigation, asked Airbus if the plane’s damage was what they envisioned. The answer; basically we don’t know as we assumed an under-power ditching.
 
kalvado
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Re: Since LAX departures are usually out over the ocean, do all aircraft need overwater equipment?

Wed Sep 29, 2021 6:40 pm

GalaxyFlyer wrote:
Okcflyer wrote:
N1120A wrote:

Most of the passengers and crew stood on the wings and were rescued by local boat traffic in the Hudson. In that situation, it was actually better that they didn't get into the water, as hypothermia was a real risk.


While the Hudson isn't exactly the most "clam" body of water, the Pacific Ocean is a whole other animal. Had Sully landed 1549 in the Pacific, it's very unlikely it would have stayed together as one piece and had the same heroic outcome.

Likewise, had that incident happened in another large metro area, the outcome likely would have been even more catastrophic than a hypothetical ditching in the Pacific as it's improbable they would have been able to find enough open space to sit her down without crashing into buildings or other ground items (Think TACA 110 and magically finding a suitable levy). These are not Cessna's and highways/roadways aren't going to work very well.

I am a bit curious as to how the regulations assume an ocean ditching would work. I assume they expect it to occur as a gradual descent from cruise with enough time to prepare the cabin,doning life vests, and possibly including fetching the life rafts from storage and getting them next to a door? It's likely that most aircraft will break up in some fashion while "landing". If this is the case, it'll be difficult to get the life rafts out once crashed. The slides are easy since they automatically inflate also serve as floatation.

In the case of LAX, the most critical period would be double engine failure immediately after take off, long before reaching the 50nm mark. It's extremely unlikely both engines fail at the same time. If one fails and you're heading away from shore, one of the higher priorities tasks should be a turn to either parallel or back to shore just in case a problem develops with the other.

The recent 737 freighter ditching in Hawaii kept flying away from land on one engine instead of going parallel with, or back to incase further problems developed.


Ditching cannot be tested during certification, so the engineering uses models, prior events and assumptions to certify. The NTSB and EASA, during the investigation, asked Airbus if the plane’s damage was what they envisioned. The answer; basically we don’t know as we assumed an under-power ditching.

THere seem to be little logic in over-water safety - the good thing there are very few events which put those precautions to the test.
There was a lot of discussion about Airbus having a button to seal all ports at the bottom to minimize water intake - but US1549 had both cargo doors open when the plane was lifted from water, in addition to partial loss/failure of the lower fuselage skin panels in the back and loss of the lower portion of the aft pressure bulkhead. So much for closing those valves.
 
TangoandCash
Posts: 85
Joined: Wed Apr 05, 2017 5:52 pm

Re: Since LAX departures are usually out over the ocean, do all aircraft need overwater equipment?

Wed Sep 29, 2021 7:09 pm

kalvado wrote:
GalaxyFlyer wrote:
Okcflyer wrote:

While the Hudson isn't exactly the most "clam" body of water, the Pacific Ocean is a whole other animal. Had Sully landed 1549 in the Pacific, it's very unlikely it would have stayed together as one piece and had the same heroic outcome.

Likewise, had that incident happened in another large metro area, the outcome likely would have been even more catastrophic than a hypothetical ditching in the Pacific as it's improbable they would have been able to find enough open space to sit her down without crashing into buildings or other ground items (Think TACA 110 and magically finding a suitable levy). These are not Cessna's and highways/roadways aren't going to work very well.

I am a bit curious as to how the regulations assume an ocean ditching would work. I assume they expect it to occur as a gradual descent from cruise with enough time to prepare the cabin,doning life vests, and possibly including fetching the life rafts from storage and getting them next to a door? It's likely that most aircraft will break up in some fashion while "landing". If this is the case, it'll be difficult to get the life rafts out once crashed. The slides are easy since they automatically inflate also serve as floatation.

In the case of LAX, the most critical period would be double engine failure immediately after take off, long before reaching the 50nm mark. It's extremely unlikely both engines fail at the same time. If one fails and you're heading away from shore, one of the higher priorities tasks should be a turn to either parallel or back to shore just in case a problem develops with the other.

The recent 737 freighter ditching in Hawaii kept flying away from land on one engine instead of going parallel with, or back to incase further problems developed.


Ditching cannot be tested during certification, so the engineering uses models, prior events and assumptions to certify. The NTSB and EASA, during the investigation, asked Airbus if the plane’s damage was what they envisioned. The answer; basically we don’t know as we assumed an under-power ditching.

THere seem to be little logic in over-water safety - the good thing there are very few events which put those precautions to the test.
There was a lot of discussion about Airbus having a button to seal all ports at the bottom to minimize water intake - but US1549 had both cargo doors open when the plane was lifted from water, in addition to partial loss/failure of the lower fuselage skin panels in the back and loss of the lower portion of the aft pressure bulkhead. So much for closing those valves.


I recall reading somewhere that the 'ditching button' was never pressed, with the copilot's attempts to restart an engine taking priority. Some airframe damage was probably caused by water impact (water isn't exactly 'soft' at A320 landing speeds), and more could have been caused when the airframe was finally hauled out of the water.
 
kalvado
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Joined: Wed Mar 01, 2006 4:29 am

Re: Since LAX departures are usually out over the ocean, do all aircraft need overwater equipment?

Wed Sep 29, 2021 7:16 pm

TangoandCash wrote:
kalvado wrote:
GalaxyFlyer wrote:

Ditching cannot be tested during certification, so the engineering uses models, prior events and assumptions to certify. The NTSB and EASA, during the investigation, asked Airbus if the plane’s damage was what they envisioned. The answer; basically we don’t know as we assumed an under-power ditching.

THere seem to be little logic in over-water safety - the good thing there are very few events which put those precautions to the test.
There was a lot of discussion about Airbus having a button to seal all ports at the bottom to minimize water intake - but US1549 had both cargo doors open when the plane was lifted from water, in addition to partial loss/failure of the lower fuselage skin panels in the back and loss of the lower portion of the aft pressure bulkhead. So much for closing those valves.


I recall reading somewhere that the 'ditching button' was never pressed, with the copilot's attempts to restart an engine taking priority. Some airframe damage was probably caused by water impact (water isn't exactly 'soft' at A320 landing speeds), and more could have been caused when the airframe was finally hauled out of the water.

That is all correct. What I am saying is that the plane sustained hair raising amount of damage with lots of newly created openings for water ingress. So the button wouldn't do much of a difference, I assume...
 
TangoandCash
Posts: 85
Joined: Wed Apr 05, 2017 5:52 pm

Re: Since LAX departures are usually out over the ocean, do all aircraft need overwater equipment?

Wed Sep 29, 2021 7:20 pm

kalvado wrote:
That is all correct. What I am saying is that the plane sustained hair raising amount of damage with lots of newly created openings for water ingress. So the button wouldn't do much of a difference, I assume...


Agree--whether the ditching button gets pressed probably won't make much if any difference.
 
GalaxyFlyer
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Joined: Fri Jan 01, 2016 4:44 am

Re: Since LAX departures are usually out over the ocean, do all aircraft need overwater equipment?

Wed Sep 29, 2021 7:45 pm

kalvado wrote:
GalaxyFlyer wrote:
Okcflyer wrote:

While the Hudson isn't exactly the most "clam" body of water, the Pacific Ocean is a whole other animal. Had Sully landed 1549 in the Pacific, it's very unlikely it would have stayed together as one piece and had the same heroic outcome.

Likewise, had that incident happened in another large metro area, the outcome likely would have been even more catastrophic than a hypothetical ditching in the Pacific as it's improbable they would have been able to find enough open space to sit her down without crashing into buildings or other ground items (Think TACA 110 and magically finding a suitable levy). These are not Cessna's and highways/roadways aren't going to work very well.

I am a bit curious as to how the regulations assume an ocean ditching would work. I assume they expect it to occur as a gradual descent from cruise with enough time to prepare the cabin,doning life vests, and possibly including fetching the life rafts from storage and getting them next to a door? It's likely that most aircraft will break up in some fashion while "landing". If this is the case, it'll be difficult to get the life rafts out once crashed. The slides are easy since they automatically inflate also serve as floatation.

In the case of LAX, the most critical period would be double engine failure immediately after take off, long before reaching the 50nm mark. It's extremely unlikely both engines fail at the same time. If one fails and you're heading away from shore, one of the higher priorities tasks should be a turn to either parallel or back to shore just in case a problem develops with the other.

The recent 737 freighter ditching in Hawaii kept flying away from land on one engine instead of going parallel with, or back to incase further problems developed.


Ditching cannot be tested during certification, so the engineering uses models, prior events and assumptions to certify. The NTSB and EASA, during the investigation, asked Airbus if the plane’s damage was what they envisioned. The answer; basically we don’t know as we assumed an under-power ditching.

THere seem to be little logic in over-water safety - the good thing there are very few events which put those precautions to the test.
There was a lot of discussion about Airbus having a button to seal all ports at the bottom to minimize water intake - but US1549 had both cargo doors open when the plane was lifted from water, in addition to partial loss/failure of the lower fuselage skin panels in the back and loss of the lower portion of the aft pressure bulkhead. So much for closing those valves.


The fuselage can’t be built to be withstand an impact like a water landing. The ditching switch is there to best configure known openings on the hull that are anticipated paths for water intrusion.
 
kalvado
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Joined: Wed Mar 01, 2006 4:29 am

Re: Since LAX departures are usually out over the ocean, do all aircraft need overwater equipment?

Wed Sep 29, 2021 7:51 pm

GalaxyFlyer wrote:
kalvado wrote:
GalaxyFlyer wrote:

Ditching cannot be tested during certification, so the engineering uses models, prior events and assumptions to certify. The NTSB and EASA, during the investigation, asked Airbus if the plane’s damage was what they envisioned. The answer; basically we don’t know as we assumed an under-power ditching.

THere seem to be little logic in over-water safety - the good thing there are very few events which put those precautions to the test.
There was a lot of discussion about Airbus having a button to seal all ports at the bottom to minimize water intake - but US1549 had both cargo doors open when the plane was lifted from water, in addition to partial loss/failure of the lower fuselage skin panels in the back and loss of the lower portion of the aft pressure bulkhead. So much for closing those valves.


The fuselage can’t be built to be withstand an impact like a water landing. The ditching switch is there to best configure known openings on the hull that are anticipated paths for water intrusion.

You see, when those pictures of the plane proudly sailing along the river were published, my mental impression was overall damage was minimal. Now I am looking again at NTSB report... and oh well, people on that plane were MUCH more lucky than I could think on the day of the crash.
So coming back to the ditch button - what is the point of valve configuration if skin panels and cargo doors are coming off? Was that ditch button just a feel-good step with no expected real-world consequencies, except maybe for use in case of airport flooding?
 
GalaxyFlyer
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Re: Since LAX departures are usually out over the ocean, do all aircraft need overwater equipment?

Wed Sep 29, 2021 8:13 pm

The purpose is to quickly close valves that could cause flooding. Damage during a water landing is unpredictable, flooding thru the cabin outflow valves is a known hazard that can be addressed. If you want a “ditchable” airliner, bring back the Boeing 314.
 
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HowardDGA
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Re: Since LAX departures are usually out over the ocean, do all aircraft need overwater equipment?

Tue Oct 05, 2021 8:31 am

N1120A wrote:
The chance of a water ditching on any departure out of LAX is so slim that it may as well be none. The SIDs that take aircraft further out are reserved for jet engined aircraft that are highly unlikely to have any engine failure, let alone multiple engine failures. The ones used for light airplanes generally keep people close to shore. Incidentally, the geography of that part of the California coast means that even straight out departures from LAX get you closer and closer to shore as you get further out, especially if you depart the north complex, and south complex departures mostly turn southeast.

In other words, it is a non issue. If you were unlucky enough to need to ditch, you're helped by the fact that you are 1) right off shore from one of the busiest, best equipped airports in the world, 2) near the one of world's busiest ports, 3) near a whole bunch of Coast Guard assets.


Probably before you were born:

https://en.m.wikipedia.org/wiki/Scandin ... Flight_933

Controlled flight into water. DC8 broke up on landing. Rafts deflated due to cuts from aircraft contact. Coast Guard took an hour to arrive, and IIRC they still had an air station at LAX. The floating nose section was towed to Malibu, so the part about getting closer to land is correct.

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