Air Asia Flight D7237 was forced to turn back to Perth from "technical issue"

[BradC]

What do you mean by "such aircraft are fully certified to fly with one engine"? Following an engine failure, or engine shut down, the Airbus A330 has to land at the nearest suitable airport.

Which can actually be determined by its ETOPS-240 rating. So if the aircraft is deemed airworthy by the pilot in command, any airport within 240 minutes flight time might be deemed suitable by the airline/pilot. I'm not defending the actions of the pilot or airline however.

[BradC]

B767 and A330 were both glided, to successful landings; by Canadian crews 

True. The B767 was mis-fueled by a Canadian crew, and it appears the A330 was mis-maintained by a Canadian crew. So while the flight crew who saved the day in both instances were Canadian, the direct cause for both failures was also Canadian. Whilst both landings were a miracle of properly trained Canadians, they could have both been prevented by properly trained Canadians. That's a draw I reckon

[boffin]

What do you mean by "such aircraft are fully certified to fly with one engine"? Following an engine failure, or engine shut down, the Airbus A330 has to land at the nearest suitable airport.

An engine failure on a twin engine aircraft is an emergency. The aircraft performance is highly degraded on one engine.

Oh, then I stand corrected. Perhaps I should have said "fully able to fly with one engine".

If an engine failure on a twin engine aircraft is an emergency, what should we call an engine failure on a single engine aircraft? 

Twin engine airliners do not have two engines for redundancy; they have two engines out of necessity.

In North America (in Canada at least), there are only two single engine aircraft that I know of that can legally carry passengers in commercial operation (Air Taxi type of operation); the Pilatus PC-12 and the Cessna Caravan. And this is because they both fly behind the very reliable Pratt & Whitney PT-6.

In a perfect world, all single engine aircraft pilots would take into consideration the possibility of engine failure when they plan their route.

 

Actually there are a heck of a lot more than that in terms of singles flying commercially, and carrying passenger.  There are plenty of aircraft around here like the DHC-3 Otter and DHC-2 Beavers, along with Cessna 206/207, and even 172s and 182s in commercial service. I can even think of a PA28 Piper Warrior II flying for a (small) airline commercially.

And lastly, it's not Pratt and Whitney that makes the PT-6, it's Pratt & Whitney CANADA.

[Gyro]

There was another serious metal ingestion type engine 'technical issue' that seriously disrupted a flight on Tuesday, also an Asian flight 

http://www.bbc.co.uk/news/world-asia-40421811

 

[VK3DRB]

I wondered how you'd feel if you were in the aeroplane's toilet and the plane shuddered like that. Or the air hostess just served you meal or drinks. Would they spill or fall off?

[BradC]

I wondered how you'd feel if you were in the aeroplane's toilet and the plane shuddered like that. Or the air hostess just served you meal or drinks. Would they spill or fall off?

If you were in the toilet that would expedite your movement, or probably create an unplanned one, and yes you and the people adjacent would all be wearing your food. Not my idea of a good time.

[IanMacdonald]

The worst part could be the captain admitting that he was scared and asking the passengers to pray.

'Why did you divert here when the other runway was closer?'

'Because I wanted the passengers to remain in their seats for safety's sake.. and this destination was conveniently on the same heading as Mecca.'

[SkyMaster]

What do you mean by "such aircraft are fully certified to fly with one engine"? Following an engine failure, or engine shut down, the Airbus A330 has to land at the nearest suitable airport.

Which can actually be determined by its ETOPS-240 rating. So if the aircraft is deemed airworthy by the pilot in command, any airport within 240 minutes flight time might be deemed suitable by the airline/pilot. I'm not defending the actions of the pilot or airline however.

ETOPS-240 is not a permission to allow an aircraft to fly for 240 minutes on one engine. ETOPS-240 is a restriction that is forcing the aircraft to fly along a route that keep the aircraft within 240 minutes of a suitable airport for landing in case of an emergency.

 

[SkyMaster]

Actually there are a heck of a lot more than that in terms of singles flying commercially, and carrying passenger.  There are plenty of aircraft around here like the DHC-3 Otter and DHC-2 Beavers, along with Cessna 206/207, and even 172s and 182s in commercial service. I can even think of a PA28 Piper Warrior II flying for a (small) airline commercially.

And lastly, it's not Pratt and Whitney that makes the PT-6, it's Pratt & Whitney CANADA.

boffin, you are correct, there is a lot of single engine commercial operations in Canada; Aerial work and Part 703. But they are all restricted to VFR (Visual Flight Rules); none of them can operate IFR (Instrument Flight Rules) with passengers.

The Pilatus PC-12 and Cessna Caravan are the only single aircraft that can operate IFR while carrying passengers in Canada. I don't know how an airline could operate profitably if it is restricted to VFR.

And thank you for pointing out that all PT-6 are build in Canada; all the good stuff is made in Canada 

 

[StillTrying]

If an engine failure on a twin engine aircraft is an emergency, what should we call an engine failure on a single engine aircraft? 

A crash ?

[Cerebus]

And thank you for pointing out that all PT-6 are build in Canada; all the good stuff is made in Canada 

Maybe, possibly, but we do know that all the best stuff's made in Japan.

[ConKbot]

If an engine failure on a twin engine aircraft is an emergency, what should we call an engine failure on a single engine aircraft? 

"On final approach"

https://en.m.wikipedia.org/wiki/ETOPS had some info on regulations on twin engine aircraft operating on one engine. It looks like aircraft that aren't ETOPS certified must remain within 60 minutes of a diversion site, and aircraft can be certified for up to 3 or more hours of range from a diversion site. Still an emergency though.

Kind of interesting that a fully functional engine, as heavily maintained as they are (or not, but that's a different story)  is only reliable enough that the risk of a second failure is only statistically small for 1-4 hours.

[Nusa]

Kind of interesting that a fully functional engine, as heavily maintained as they are (or not, but that's a different story)  is only reliable enough that the risk of a second failure is only statistically small for 1-4 hours.

That would depend on why the first engine failed, which is often not known until after landing. Things like bad fuel or faulty maintenance procedures could mean a 2nd engine failure is coming.

[Brumby]

If an engine failure on a twin engine aircraft is an emergency, what should we call an engine failure on a single engine aircraft? 

A crash ?

If an aircraft has some altitude to work with, the pilot will be able to do something.  Whether they can make a successful landing or crash, depends on the terrain within their range.  As said earlier - an unpowered aeroplane becomes a glider.

There is a similar capability in a helicopter, called autorotation - but from my limited understanding ... it's much more challenging than a fixed wing glide.

[james_s]

Kind of interesting that a fully functional engine, as heavily maintained as they are (or not, but that's a different story)  is only reliable enough that the risk of a second failure is only statistically small for 1-4 hours.

That would depend on why the first engine failed, which is often not known until after landing. Things like bad fuel or faulty maintenance procedures could mean a 2nd engine failure is coming.

Or bird strikes, which as we saw a few years ago can take out both engines. If there is something around to be ingested by one engine, there's a reasonable chance it will be ingested by one or more of the other engines.

[BradC]

ETOPS-240 is not a permission to allow an aircraft to fly for 240 minutes on one engine. ETOPS-240 is a restriction that is forcing the aircraft to fly along a route that keep the aircraft within 240 minutes of a suitable airport for landing in case of an emergency.

You are, of course, absolutely correct. I really didn't communicate myself properly when posting that. What I meant was that it is entirely possible that Air Asia don't even have Learmonth listed in their flight manuals as a suitable diversion, and as such Perth was the closest "suitable" diversion still within the ETOPS-240 allowance that the flight crew were "aware" of. Qantas use it, but different airline with different operating procedures.

Again, it'll all come out in the investigation.

[Yansi]

If an engine failure on a twin engine aircraft is an emergency, what should we call an engine failure on a single engine aircraft? 

A crash ?

If an aircraft has some altitude to work with, the pilot will be able to do something.  Whether they can make a successful landing or crash, depends on the terrain within their range.  As said earlier - an unpowered aeroplane becomes a glider.

There is a similar capability in a helicopter, called autorotation - but from my limited understanding ... it's much more challenging than a fixed wing glide.

Thats when the gyrocopters come into place!

[boffin]

Or bird strikes, which as we saw a few years ago can take out both engines. If there is something around to be ingested by one engine, there's a reasonable chance it will be ingested by one or more of the other engines.

We've actually had four-engine ingestion (747s) a couple of times with aircraft flying into ash clouds (once over Indonesia and once over Alaska jump to mind).

[langwadt]

Another possible solution to the vibration problem would be to break off a turbine blade at the other side of the fan, thereby restoring the balance***.

Finding a hacksaw and a volunteer to go out on the wing might be a problem though.

EDIT:
*** Yes, I am joking.

for the first jet powered land speed record Breedlove had some how gotten hold of  a scrapped jet engine from an F-86
with a few missing turbine blades, it was balanced by removing opposite blades and ran like that

[langwadt]

What do you mean by "such aircraft are fully certified to fly with one engine"? Following an engine failure, or engine shut down, the Airbus A330 has to land at the nearest suitable airport.

An engine failure on a twin engine aircraft is an emergency. The aircraft performance is highly degraded on one engine.

Oh, then I stand corrected. Perhaps I should have said "fully able to fly with one engine".

http://avherald.com/h?article=4a53bdae&opt=0

747 going from Denver to Franfurt, lost an engine over Canada, continued 5.5 hour across the Atlantic and landed
in Franfurt




Many years ago, I was privileged to be part of a group that was given a ground tour of a 747.  After walking past a 707, this thing looked HUGE ... and so did the engines.

Inside, we had a ground engineer escort us around and I had an opportunity to sit in the co-pilot's seat - and under the direction of the engineer, pushed some buttons!  One of those brought up a display showing the air pressure in every one of the tyres.  Very cool.

We then talked about the engines - and we were told that the 747 only needs the four engines to take off.  So, yeah, it needs 4 engines.  A fully laden Jumbo can fly and land on 2 - and an empty one on a single engine.  So having these capabilities and knowing about them is essential in being able to assess a course of action in an emergency.  They are not something you should plan on.

I asked what happens if, say, two engines failed on the same side of the aircraft - obviously curious on the resulting yaw moment.  The reply came: "That's when the pilots earn their money".

It would seem very clear designing such capabilities into aircraft - especially passenger carrying commercial aircraft - has been around for a very long time.  Further, inasmuch as much as we have had examples of aerial mechanics, that is not the norm.  Problems need to be managed in the air since you can't just "pull over".

[CatalinaWOW]

Not being an Aussie, and not wanting to spend time Googling this I don't know what the ground situation is at Learmouth this time of year.  Passenger injury or even death is possible at some remote airports from cold, heat exhaustion, critters, transportation injuries, delays in receiving urgent medication and gosh knows what.  So it may not have been as cut and dried a decision as it seems to some.  The pilots got to sit there in real time and make a decision.  In retrospect their decision turned out OK. 

All of us internet warriors and the transportation safety boards get to make a leisurely decision with little or no personal consequences from the outcome.  Hurrah for us!

[noidea]

Not being an Aussie, and not wanting to spend time Googling this I don't know what the ground situation is at Learmouth this time of year.  Passenger injury or even death is possible at some remote airports from cold, heat exhaustion, critters, transportation injuries, delays in receiving urgent medication and gosh knows what.  So it may not have been as cut and dried a decision as it seems to some.  The pilots got to sit there in real time and make a decision.  In retrospect their decision turned out OK. 

All of us internet warriors and the transportation safety boards get to make a leisurely decision with little or no personal consequences from the outcome.  Hurrah for us!

Googling's not that hard
https://www.google.com.au/maps/place/22%C2%B014'24.2%22S+114%C2%B005'36.4%22E/@-22.2400081,114.0938326,339m/data=!3m1!1e3!4m5!3m4!1s0x0:0x0!8m2!3d-22.24005!4d114.093437
Shelters not an issue there's an air conditioned terminal building as per my previous post and the weather is pretty mild this time of the year ~25C, it actually rained every day I was there two weeks ago.
There's some pretty robust discussion going on still in the pprune thread posted earlier about what constitutes a "suitable airport". If they were looking for somewhere suitable to put it on the ground in a hurry it fits the bill, its long enough that C-141's used to fly in and out every week when the US/Aus naval communications base was in full swing and other airlines have used it an emergency below, ie QF72  https://en.wikipedia.org/wiki/Qantas_Flight_72
My guess the lack of firefighting equipment may have had something to do with their decision but if the plane was potentially going to go up in flames I'd rather it be off the ground with the passengers sitting on the runway than flying nearly 2 hours back to Perth...

[Howardlong]

If an engine failure on a twin engine aircraft is an emergency, what should we call an engine failure on a single engine aircraft? 

A crash ?

Not really, I've landed countless times in a SEP* with no engine. Operations without an engine are a key, and significant, part of SEP pilot training. This also includes methods of picking convenient places to land that doesn't include built up areas.

*SEP: Single Engine Piston fixed wing aircraft

[coppice]

If an engine failure on a twin engine aircraft is an emergency, what should we call an engine failure on a single engine aircraft? 

A crash ?

Not really, I've landed countless times in a SEP* with no engine. Operations without an engine are a key, and significant, part of SEP pilot training. This also includes methods of picking convenient places to land that doesn't include built up areas.

*SEP: Single Engine Piston fixed wing aircraft

I find it strange that almost everyone knows that gliders exist, yet many assume a powered plane will plummet as soon as its out of power. The only type of aircraft in danger of that today are advanced military aircraft, which require a mass of clever gizmos functioning normally to have any stability. It may happen that future civilian aircraft move in the direction of no inherent stability, but none are like that today.

[james_s]

They won't plummet, but they won't glide nearly as well as a plane that is designed as a glider, and if you're not expecting to be without power you may not have much time to find a suitable place to land. A true glider can remain in the air for a rather long time utilizing thermals to gain altitude, a powered aircraft with a dead engine is going to go down fairly quickly.