Over water
 

I'm not sure this is the right Forum, apologies if it isnt.

Can spmeone answer ,y question please. I'm a pax, not in airline business. I was wondering what would happen if there was a problem with a plane if you were flying over a large body of water , like the Atlantic. I mean if you are half way over, and there was a problem that you HAD to land the plane. How does that work?

Thanks

Hi,

People with more knowledge can probably give you more detailed information but...

If you HAD to land (e.g. all your engines quit) I'd imagine your first choice would be an airfield within gliding range, your second choice would be land of some sort (if more suitable than the third choice) and your third 'choice' would be to ditch in the ocean. I can only think of two obvious scenarios where you'd have to consider landing without delay - all engines quitting or an uncontrollable and spreading fire.

Thankfully, modern engines are extremely reliable and airliners crossing remote areas such as the ocean and desert have to be approved for doing it. Twin-engined airliners have something called ETOPS (Extended Range Twin Operations) approval which stipulates the maximum time/distance that a particular aircraft can fly away from a suitable airport at which it can land. ETOPS approval takes into account one of the engines failing and the remaining flight continuing with one engine. Fuel planning is also very thorough and plenty of spare is carried to ensure an aircraft doesn't run short of fuel.

Years ago people used to frown about crossing desolate areas with anything less than 4 engines but, due to advances in reliability, twin-engined airliners crossing the pond is now the norm.

In the worst case - an airliner having to ditch in the sea, you might be heartened to know that there are more than enough life jackets and life rafts for everybody on board, by law. Even so, ditching an airliner in the sea must be extremely hazardous, risky and a last resort.

There was a recent (ish) incident where a twin-engined AirTransat Airbus (330 I think) ran out of fuel over the Atlantic with the inevitable result that both engines stopped. The crew managed to glide the aircraft to a landing at a remote military base on an island. Must have been a huge brown-trousers moment for all involved :bored:

Hope this is useful,

V1R

Most modern a/c that fly over large expanses of water are generally ETOPS (Extended twin operations) approved. Without going into too much detail, it basically means that the a/c must be able to reach an airfield to which a landing can be carried out successfully within an alloted period of time, after suffering the loss of an engine(s). This period of time is based upon how much ETOPS time is granted or certified to that aircraft & its engine type.

The most basic ETOPS started out at 60mins, however today some a/c - the Boeing 777, has a 208 mins ETOPS - (any B777 pilots feel free to correct me if I'm wrong, as I come from the Airbus stable). Engine technology has moved the game of reliability so far forward that it is very rare these days to see an engine failure. Even if you do suffer one, the remaining powerplant(s) will be sufficient to get you safely back on the ground or to your destination.

Hope that answers some of your points
HPC

Many Atlantic routings arent that far from airports anyway. Typical routing to say Toronto takes you over Scotland, visible to Iceland and Greenland, (Azores or some other Island?), Newfoundland and over land in Canada. Even more northerly for the likes of SanFran and LA.

If a pro sees this thread it would be interesting to know the worst case flight time to a suitable runway. Dare say Pacific is a bit different.

Indeed - no-one has ever successfully ditched a commercial jet airliner with under-wing engines in open water. Frankly, by any reasonable risk-benefit analysis life jackets, rafts etc would be taken out of aircraft immediately. The damage to the environment caused by all the extra fuel that has to be burnt to carry those items far outweighs a hypothetical benefit.

Another view -

Although LifeJackets/Rafts/SlideRafts are very far from an ideal, they do. at least, represent some hope for the occupants. Their removal could arguably be proposed on cost/benefit grounds, but in human terms (i.e. customers) the idea would surely be unacceptable? People dervive some degree of comfort from the knowledge that they are there, and that a plan, at least exists, for survival in ditching.

For example, I have my own plan for a ditching - after evac you will be able to find me with ease in the water - I shall be tethered by the lanyard on my LJ to both ELT's; an infant life cot, also tethered will contain the crew food (shark deterrent) and 800 Silk Cut (it could be a long wait). I shall be sitting on the largest Slideraft, holding onto the Liferaft.


In darker moments, I've sometimes though that this philosophy may also apply to some of our customers. :E

Indeed, but these are probably the same people who think that stopping you from bringing a normal tube of toothpaste onto a plane somehow makes it safer. I simply can't agree that pandering to the sheeples' ignorance is a good basis for policy-making.

What about a situation where the aircraft over runs the end of the runway and into the sea. Evacuation into water may require lifejackets etc.

As i understood from a previous post i was reading there wasnt any land between lands end and ummm i think Dominican Republic or some place in the caribbean, so where would the A/C go if in trouble between those two points then? :bored:

Well, for starters there may not be enough time to grab your lifejacket and don it. Plus, in that scenaril you are likely so close to shore that you can easily swim there. Swimming without an (inflated) life vest is significantly easier than with an (inflated) vest.

But frankly, I don't think it's even going to get to that stage. Large airliners are not built as one solid alu tube. Instead, they are built in sections that are bolted/welded/glued together, and these joints are comparatively weak. The stresses involved in ditching a large airliner are, I think, so great that there's a big chance the plane will break apart on or near these joints. Apart from the immediate danger to the people sitting close to such a joint from torn metal, it also means that the pressure hull is now compromised and buoyancy will be reduced to zero so it'll sink like a stone. (Obviously airliners don't have watertight compartments like Titanic had.) If you're not able to get out immediately, you might not get out at all.

And here's another consideration. Next time you're on a flight, take a close look at the safety card in the seat pocket. Look for the picture where the plane is in the water and people are evacuating onto the slides doubling as rafts. Look at the size of the waves, if the author drew any waves at all. Also look at the height of the 'freeboard' - the distance between (average) sea level and the underside of the door. Now picture this happening in the Atlantic, where the swell, on a good day (after at least three days of light winds), might be 50 centimeters, and far more than that on a bad day - 6 meters not being uncommon. Pacific swells are even worse. (Google for atlantic swell height - the height of the swell is so important for certain kinds of offshore traffic that predicting swell height is a standard task of weather forecasters.)

Christep already said it. Nobody has successfully ditched a modern airliner yet. Ever. Pilots know these statistics and will try to avoid ditching at all costs. Crossing large bodies of water requires a serious amount of planning and conforming to safety regulations and even then there are rules on how far you may be from the nearest suitable airport. These rules (ETOPS being one of the rule sets) depend on the aircraft type and engine type, but also on operator procedures for e.g. maintenance, and crew licenses/experience. And the safety record is excellent because of this!

Atishoo,
Simple answer to your question - the Azores.
If you're interested, follow this link http://gc.kls2.com/
For any two given airports, it shows you not just the likely great circle route between them, but (by clicking on various ETOPS flying time options) whether you're in range of potential diversion airports.
For example, if you enter Gatwick (LGW) and Puerto Plata (POP) and select an ETOPS rating of 90 minutes, you'll see that even for such a long over water flight, there's only a short section of the route where you would be more than 90 minutes from an airport.

Nimrod. - ok mil airframe, but a comet by any other name!

What about the Ethiopian in the Comores? Yes I know that the port wing/engine hit first and the a/c cartwheeled, but people got out of that because of lifejackets, but also people died because they inflated theirs while still in the a/c.

The Nimrod is pretty good at ditching. Remember seeing a photo of the R3 sitting complete in the Moray Firth.

Backpacker Yes, I have looked at those cards often and often considered the imprecise nature of ditching a modern airliner (there's an old fashioned word!) and I have decided to accept those risks for the benefits.

When I travel on the London underground/New York subway, I take the risk that there will not be a fire/bomb/deranged person/flood/earthquake at the time I am using it and I have decided to accept those risks for the benefits.
True and the good news is that, if you have a really bad failure whilst over sea OR land, then you probably won't have to worry as the speed of impact will take care of everything very quickly.

I have not seen any stats about a/c that develop problems resulting in an immediate divert, separated by the incident starting over land or water. My guess is that, if a problem develops fast, it may make little difference where you are. The risks of not making the field are also balanced with - arriving at the approach to the field but then not being able to complete a safe landing as the fault has developed in an unpredictable way.

If a major event begins, my guess (note 'guess') is that you will have a handful of minutes to get down and if at FL360 that may not be sufficient, even if in Europe with dozens of alternatives. From what I (as an amateur) have read, problems tend to mostly fall into the category 'Minor - they made a precautionary divert and the fault did not get worse' and 'Major - they diverted but the fault was too fast and they did not make it'. There are a few, rare, occasions when a major fault leads to a long and difficult divert with a tricky landing and minimal casualties. That's why they make movies about them because they are so rare.

For Atishoo and other nervous pax, the above is probably of no help but the facts remain that the number of passengers delivered uneventfully to their destination is staggeringly high. The maintenance and operational process' in place ARE working.

I recall China Airlines (see other postings) chalking up a first for Hong Kong back in 1992 I think: the first flotation test on a 747. They ran off the runway and the a/c was perfectly intact. P-GASH no fatalities, and for that matter no injuries either if you exclude pride (what pride?).
So in a slow situation the a/c can be ok. I don't think life jackets helped in that case.
BTW a couple of weeks later I had to go to Taiwan and Cathay Pathetic was fully booked (reason being bloody obvious). My secretary had to pop downstairs to China Airlines to pick up the ticket. I asked her to put in a request for the free harbour tour on the trip back to Hong Kong. When she came back she was NOT happy.

I find the life jacket demonstration the most frustrating period of any flight, especially one where you know you are not going over water. I try to be attentive and obedient but it does test my resolve.

Give me a smoke hood instead of a life jacket any time.
The risk of noxious fumes from a small fire onboard is, in my uneducated and non-technical opinion, of a higher risk and more likely to be survivable with appropriate equipment than having the opportunity to use a life jacket.

Nimrod is presumably pretty good at ditching as it doesnt have underslung engines and therefore has a cleanish underside which allows it to sail like a boat on water!

I always find the lifejacket section of the safety briefing rather amusing on my regular flights from UK to Holland as the only sea I'm going in is the North Sea and I'll last about 15 mins before dead from hypothermia if I'm lucky, even without having suffered a ditching first...All seems a bit pointless for the more northerly sea crossings...

Edited to add:

...however, I do appreciate that it is appropriate to have a standard(ish) briefing the world over, as the lifejacket situation is rather more relevant the closer to the equator you get. And if it also helps to soothe some nervous flyers, then its all fine and dandy :)

It is, however, a shame so many individuals continue their conversations during the briefings with scant regard to those who wish to listen/watch :ugh:

I fly EDI to LHR and back every week.

I can't remember if we fly directly over Windemere or not...


;)

Seriously though, I do appreciate the reasons for having standard briefings

How many attempts have been made?

Groundhand: "I find the life jacket demonstration the most frustrating period of any flight, especially one where you know you are not going over water. I try to be attentive and obedient but it does test my resolve."

So how about when an aircraft "you know" is not going over water gets diverted Groundhand? And are you sure "you know" every bit of water on your route? I know it's unlikely but what if you crash landed in the huge body of water that is the reservoir just outside LHR? Might sound stupid and it's incredibly unlikely but you could lose a jumbo in there!! Surely it's best to be prepared, just in case... that's what accidents are all about.