PDA

View Full Version : 777 ditching not simulated?


lynn789
27th Jan 2010, 20:27
having recently crossed the pacific in a 777, I was impressed by all the water down there and the fact that we only had 2 engines, with many cases of one failing in flight
later I heard that 777 pilots do not practise ditching on their simulators, is this correct?
theres been discussion on ditching a modern airliner with worries about the engines digging in on touching the water with some saying the shear pins would allow the engines to break off, it now seems that this wont happen and the ditching must be done tail down

Offchocks
27th Jan 2010, 20:38
Ditching is an extremely rare event and in 30 years of doing simulators on various types, I have never practiced it.

lomapaseo
27th Jan 2010, 21:25
having recently crossed the pacific in a 777, I was impressed by all the water down there and the fact that we only had 2 engines, with many cases of one failing in flight
later I heard that 777 pilots do not practise ditching on their simulators, is this correct?
theres been discussion on ditching a modern airliner with worries about the engines digging in on touching the water with some saying the shear pins would allow the engines to break off, it now seems that this wont happen and the ditching must be done tail down

Some of the presumptions to your question are not valid.

The inflight mandatory shutdown statistics make it is extremely unlikely that a ditching will occur over water on a long haul flight.

Shear pins are designed to break before the wing breaks, assuming the plane lands on its engines. If the impact is great enough both may break.

Ditchings are like crashes into a wall in your automobile. It makes little sense to train for all the variations. The training concentrates on avoiding them

763 jock
27th Jan 2010, 22:06
Pacific Ocean or Hudson River? What about a dual engine failure over any large city? I've never been trained in how to do a forced landing in the Alps at night.

You simply cannot "train" every conceivable/possible scenario.

sitigeltfel
27th Jan 2010, 22:19
Not my usual forum lynn 789, but you may want to look at this.

As well as the Hudson river incident there was the hijacked Ethiopian 767 ditching off Africa, after running out of fuel. The captain was still fighting with the hijackers when they splashed down. This probably caused the dropped left wing.

aqV1byLOmNc

bfisk
28th Jan 2010, 10:16
with many cases of one failing in flight
This is a can of worms.

Yes, even modern turbofan engines, do on occasion, fail. And that is why not everyone is allowed to take any twin engine aircraft and fly anywhere
Wikipedia has a good article about who can (http://en.wikipedia.org/wiki/ETOPS). It basically talks about the ruleset called ETOPS; Extended range twin-engine operations. It should explain why things are as safe as they are.

PappyJ
28th Jan 2010, 10:52
later I heard that 777 pilots do not practise ditching on their simulators, is this correct?


Not entirely. Ditching has never - to my recollection - been included in any manufacturers recommended training programs. However, I am aware of several airlines which included such training following the Sullenberger experience.

That said, ditching in an Airliner is an extremely unlikely event to occur.

In fact, "Sully" probably got the Staticstical "...one in whatever many..." for the remaining century!

Cheers

lomapaseo
28th Jan 2010, 13:26
PappyJ

That said, ditching in an Airliner is an extremely unlikely event to occur.

Well really not that unlikely at the beginnig or scheduled end of a flight :)

Several forced landings shortly after the beginning and even a few near the scheduled end. Many of which involved fatalities

StallBoy
29th Jan 2010, 03:24
Having crossed the Pacific many times in 747's I think only the brave or stupid would do it in a plane with 2Xdonks:eek:. Even Smithy had more sense:ok:

AnthonyGA
29th Jan 2010, 04:39
Didn't I read somewhere that ETOPS was being reconsidered after several incidents in which all engines failed for reasons other than mechanical failure of the engines themselves? I think it had something to do with severe icing conditions that could stop all engines and had not previously been recognized as a hazard, but I don't remember the details.

Also, Sully wasn't the first. There was a Russian airliner that ditched on a river in the early '60s with all crew and passengers surviving.

From the stats in the Wikipedia article it looks like ditching overall is no more hazardous than an emergency landing on dry land. It seems that the landing surface isn't nearly as important as maintaining the aircraft in controlled flight until touchdown.

PappyJ
29th Jan 2010, 04:46
It seems that the landing surface isn't nearly as important as maintaining the aircraft in controlled flight until touchdown.

That's the most accurate statement thus far!

mad_jock
29th Jan 2010, 05:08
Another technical hitch is the fact that the sims can't actually simulate a water arrival.

The dynamics/model would be hurrendous to simulate.

I have done dual engine failures in my icle turboprop sim sessions but after you run the checklist they given you at least one back for the rest of the session.

At the end of the session with spare time I have also done a dual failure with pilot incapacitation from FL200 over Manchester with a glide to land. Yep its was good fun, but for line flying not much training benifit compared to doing all the other good stuff.

777AV8R
29th Jan 2010, 05:12
Training time in the simulator is short enough as it is. To conduct an exercise of this nature would use up valuable resources that could be used practicing something constructive.

bauduin_alex
29th Jan 2010, 08:20
A simulator does not "invent" reactions, it is a reaction of mathematical model validated against flight tests data from Boeing, sometimes engineering data. So if you wish to see a ditching scenario in the box, you might ask Boeing to ditch one of their 777 and hope that all the data collected during the ditching are good.

Tee Emm
29th Jan 2010, 12:02
Training time in the simulator is short enough as it is. To conduct an exercise of this nature would use up valuable resources that could be used practicing something constructive.It is that type of negative thinking that gets right up my nose. Have you ever tried to practice the pure instrument flying skill in the simulator where the success or otherwise of a premeditated ditching depends primarily on the correct attitude and airspeed on touch down in IMC (night)?

I doubt it. The 737 FCTM dedicates this advice for final approach to ditching: "Maintain airspeed at VREF. Maintain 200 to 300 fpm rate of descent. To accomplish the flare and touchdown rotate smoothly to touchdown attitude of 10 to 12 degrees. Maintain airspeed and rate of descent with thrust.

Now read the Ditching part of the QRH. There are three pages devoted to the ditching drills. Believe me, I have personally witnessed almost every pilot who attempts the ditching final approach on instruments in the simulator for the first time, ignominiously hit the "water" at excessive rate of descent or fatal body angle.

Of course ditching impact forces cannot be truly replicated in a simulator. In any case the OH & S ramifications would be mind boggling. But certainly the normal simulator flying characteristics up to touch down in the water ensure fidelity - and it is the instrument flying involved in the final approach below 500 feet where pure flying skills are essential to success. Those who complain of degradation of flying skills in automated aircraft are going to be in trouble here.

To put this into time perspective. The last 500 feet to impact is where the real flying skill (or absence of) shows up. Incorrect nose attitude, rate of descent or airspeed during that time, and the chances are of survival are minimal - especially if the body angle at touch down is not optimum for aircraft type. Worst of the lot is nose down at impact - grimly termed torpedo effect. Automatic pilot monitoring skills won't help you now. . Excellent basic handling skills are the key to survival - or certainly reduce the chances of a disaster.

Assuming a ditching final approach to sea level from 500 feet takes two minutes. Assume each pilot repeats this two or three times for the first time he has a go in the simulator. Because chances are there will be need to be repeats. So for a lousy (say) six minutes of hands-on flying per pilot in the simulator per year, a skill of inestimable value is attained and hopefully retained.

Like a tyre burst nearing V1 in the simulator, or a blocked static vent on take off, an instrument ditching is considered by some to be so improbable that they feel it is a waste of valuable simulator time. Where do you stop with this theory? I would guess an engine failure at exactly V1 in IMC is as highly improbable as a ditching. Yet they are practiced in the simulator,ad nauseum.

Twin engine aircraft flying over thousands of miles of ocean are common place. It must be really comforting to passengers and flight attendants to know the cockpit crew have no idea how to ditch, since simulator time is too valuable to practice for six minutes each year....

Tal66
31st Jan 2010, 11:51
:D @ Tee Emm
Best post I have seen on this site, I even went to the trouble of working out my login.

GlueBall
31st Jan 2010, 12:53
Capt Tee Emm: Just one clarification, please: In your second paragraph on ditching you say: "Maintain airspeed and rate of descent with thrust." . . . so, if you had thrust, why would you need to ditch? :ooh:

Spooky 2
31st Jan 2010, 13:59
Back around 1998 or so Delta Air Lines sponsered a ditching/water survival seminar at it's training center in Atlanta, GA. We invited virtually anyone with an interest in this subject to attend the two day event. The opening speaker was one of Delta's F/O's who had the unfortunente experience of being the co-pilot on a USN, P3 that had ditched south of Petropovlosk back in the early eighties. Of the fourteen crewmembers on board only four or five got out alive and were in turn picked up by the Russian Navy. Actually most of the crew got out, but do to very high seas and extreme wind, they were unable to board rafts and thsu blew away from the resucers. Interestingly the aircraft commander had at one time been a pilot on the USN Marlin flying boats and his skills at getting the P3 on to the water with minimal damage were credited to his previous flying boat experience. As the pilot told the story, you could have heard a pin drop from 100 yards. It was truely spell binding

While I would not take anything away from the USAir crew that landed on the Hudson, there have been several controlled ditchings in the past that far exceed the challenges that this USAir crew experienced. Northwest Airlines ditched a DC7C outside of Manila, at night while on fire after losing a prop which penetrated the cabin, in high seas and only lost one passenger after spending around eight hours afloat in the sea.

Pan American lost two Stratocruisers with minimal loss of life on one, and none on the other. To my knowledge other than a ONA DC9 that ditched in the Carribean after runing out of fuel, there have been no planned ditchings. A few water landings maybe but planned, controlled ditchings I would venture to guess may not have happened....yet.

lynn789
31st Jan 2010, 19:33
thanks for all replies, the recent boeing stratoliner event comes to mind

Spooky 2
31st Jan 2010, 19:45
Ah yes, how could we have forgotten that one. Some of Boeing's finest having to use their exception skills to keep their butts out of a real disaster.

John Farley
31st Jan 2010, 19:49
GlueBall

Why would you want to ditch if you had power?

Running out of fuel and on fire are two obvious cases.

Spooky 2
31st Jan 2010, 21:57
Somebody obviously did not read post #18

lomapaseo
31st Jan 2010, 22:46
Somebody obviously did not read post #18

Perhaps you should develop the message a little bit more for the speed readers among us.