Single Engine turboprop crossing the North Sea

[800driver]

Whilst playing with flight radar with the Kids I noticed that on many occasions we would se a PC12 flying between Scotland and Norway straight across the North Sea. Now perhaps I'm too old school (I remember ETOPS being a major discussion ) but single engine at night over the North Sea would give me the collywobles. id be interested what you younger aviators feel about single engine ops over the water imc at night etc.

[what next]

...what you younger aviators feel about single engine ops over the water imc at night etc. Define "younger" first ;-)

Personally, I can not imagine that I will ever be desperate enough for flying time and/or money to do that myself. And flying privately even less so. But then, what do I know about the future?
And about day or night I really don't know if that makes any difference in these waters. You either wear a full immersion suit and carry a raft for the least chance of survival or you will drown a either way.

[FerrypilotDK]

Having flown 217 across both the Atlantic and the Pacific, I might not be the right one to ask......or I am. Scotland to Norway.....Nome to Kyoto, St Johns to Azores, Goose to Reykjavik and California to Hilo Hawaii, the longest overwater stretch you can find.

It can happen at any time on any engine, but the statistics have convinced EASA that AOC, single-engine turboprop is now permitted. So......I don't want you to lose sleep, so not a word about the single-engine pistons! ;-)

[Manual Reversion]

And interestingly,a plan to use Cessna caravans out of the Channel Islands with two uk caravan engine failures in the last six months. I'm not a betting man,but.....

[fleigle]

New TBM's are delivered to N. America from France all of the time, this is 2017, not 1917 !!!
f

[megan]

this is 2017, not 1917A failure is a failure no matter the year. The PT6 has a good reputation but never the less. SIL had a PT6 spit the chips recently on initial climb, and it had only 1,000 hours since brand new, fortunately he had a spare to carry him home.

A young lady at night and her experience.

http://www.atsb.gov.au/media/3483038/ao2010006.pdf

[tume]

We just decided against this route recently, flying Finland to North England. Crossed south over Netherlands instead.. and yes, the flight was much longer.

[what next]

...but the statistics have convinced EASA...Yes, maybe. But I am not a statistic and I don't want to become one. I am an individual and for me, the probability that the engine will fail on my next flight is exactly the same than as it will fail on my thousandths flight (at least this is what they taught me in maths back at school). A bit like 200hp motorcycles. Statistically they seem to be safe enough that that lawmakers allow them to be sold to anyone and driven on public roads. Yet my own sense of self-preservation tells me to do the smart thing and stay away from them.

[ion_berkley]

I know about this incident having discussed a ton of scenarios with my buddy before he flew RTW in his PC-12 last year. Nice to know that its proven possible to ditch one safely in real world IMC at least once: https://aviation-safety.net/wikibase/wiki.php?id=17025

[Albus_Dumbledore]

Manual Reversion,

Do please provide us with the two examples in the UK.

Albus

[Deep and fast]

I would rather do it in a PC12 compared to the seneca I used to go across there in!

[stilton]

Why is that ?

The PC12 is an impressive aircraft by all accounts but still a single and if your one engine fails you're just in an expensive glider.

I flew some ancient clapped out Barons in another life, single Pilot night freight but I'd still prefer its extra engine compared to your chances in a single across the north sea.

[what next]

I flew some ancient clapped out Barons in another life, single Pilot night freight but I'd still prefer its extra engine compared to your chances in a single across the north sea.

Same here. Back in those times, one of my colleagues once did a precautionary shutdown on one engine (in a C404 IIRC) over Spain and flew all the way home to Germany on one engine in the middle of the night. Try this with a single...

[Piltdown Man]

Piston twin or turbine single? No contest really.

PM

[flyhardmo]

Flown both. I'd take a single turbine over a a piston twin any day.

[Vzlet]

"...upon breaking through the bottom of the last overcast layer, at 100 feet above the water..." :eek:

[ChickenHouse]

Reliability of the PT6 is easily comparable to a piston twin, if not better, so no trouble for PC12, TBM8/9xx to take these routes. If I would have to choose, I'll take the PC12 over a light twin. And, I prefer quick death in North Sea over lingering illness as well ;-).

[spittingimage]

Over water, at night ? In SEP, even ? Been there, done that, many times transAtlantic .. and got away with it :} ! I don't do it any more these days though.

But it is quite routine : just Google 'OTTspotters' that monitors North Atlantic ferry traffic. There's usually a sprinkling of singles the year round crossing lots and lots of water. Twins are more common though.

[Sillert,V.I.]

Back in those times, one of my colleagues once did a precautionary shutdown on one engine (in a C404 IIRC) over Spain and flew all the way home to Germany on one engine in the middle of the night. Try this with a single...

From the moment your colleague shut down the engine, they were effectively flying a single across Europe in the middle of the night, and one with less performance than most. IMO a questionable decision not to land at the nearest suitable airfield.

[AndiKunzi]

Comparing SET to MEP:

A PT6 may have a MTBF (including prop, fuel, etc.) that is 10 times higher than that of a well maintained piston engine, which would result in 20 times better engine reliability in a SET than in a MEP. It is very difficult to get good data, so this is just a very rough guess looking at accident data.

So for initial climb, which is critical in most cases in a MEP, you are safer in a SET, especially if pilot skills are not excellent and climb out is difficult. However, for long flights over water, mountains or remote areas or in bad weather, especially at night, a MEP will offer much more safety if handled by a professional pilot and by the book. Most turbocharged MEPs will provide sufficient single engine performance after initial climb, at most places.

If MTBF on a piston is 1 per 10,000 hours, the probability to lose the second engine when within 1 hour of an alternate in average is 1:5,000 (OEI) * 1:10,000 (second engine out within one hour). This, of course, requires to save the good engine.

A Seneca III will keep you OEI at 14,000 ft on an ISA day with full tanks on departure and 4 pax. A Cessna 421C with the same loading will maintain 20,000 ft on one engine. At MTOM, which is full tanks and 500 kg of crew + pax on the C421C I fly, the ISA single engine service ceiling is 15,000 ft. In most cases, 70 % MCP will get you a good single engine cruise above all you want to clear.

I would not frequently do flights in a SET in conditions where an emergency landing would probably be lethal for me or my passengers. Evacuating a child or older persons after ditching and getting them in a raft would be a nightmare even if it is the Mediterranean Sea in summer. I feel SET - either new or used - are way overpriced compared to MET (e.g. a new King Air or a used Conquest) or MEP.

Reliability on many piston engines is largely affected by maintenance and pilots. Turbines are seeing professional handling and pilots in most cases. The engines are not guilty if the owner doesn't care and the pilot doesn't either.

[stilton]

These single engine turboprops are really impressive aircraft, very comfortable with sophisticated avionics and impressive performance but no matter how good they are and some have good systems redundance they lack the most critical redundancy, an additional engine !

This can literally be a life or death situation, there are numerous occasions where losing your sole powerplant will result in catastrophe, all the statistics in the world won't help you then.


I'd still take a piston twin, or preferably a twin turboprop over a SET no matter how nice.

[AdamFrisch]

I couldn't stomach it in a single, despite the excellent reliability of SETP. I bought my Turbo Commander for about a 10th of what a used PC12 costs. The Garrett's burn the same amount of fuel as the single PT6 and both of them together cost less to overhaul than the big block PT6's. And have longer TBO. OK, it's old, probably looks a little funny to some and it doesn't have the new plane smell, etc. Still about $3million cheaper. Listen, I love the PC12, think it's an awesome machine, I'm just always surprised at the financial lengths people will go to to just to fly something that's new, but has no performance or cost benefit.

Even sadder is how that reflects on aviation: no real performance advancement/economic advantage has been achieved in about 40 years....

[stilton]

Good points AF,

Does anyone other than Beechcraft and Piaggio make twin turboprops anymore ?

[AdamFrisch]

No, and you know why, right? Because everyone wants jets, although it costs them more. And frankly, the way Beechcraft charges for King Air parts, I think the KA line eventually will end, too. Many Citations are today cheaper to run than a King Air just because of Beech's pricing.

The P180 is the only real leap in technology in aviation in those 40 years. And the market has largely rejected it, because aviation is as conservative as the Spanish Inquisition. ;)

[what next]

The DHC-6 Twin Otter and the Dornier 228 (now called Do 228 NG and manufactured by RUAG) are still in production. They are in the same 6-ton class as the larger KingAirs. There are a few more twin turboprops in the utility category / light military transport being produced somewhere in the world. This category of aeroplanes is not dead yet!

[ChickenHouse]

The DHC-6 Twin Otter and the Dornier 228 (now called Do 228 NG and manufactured by RUAG) are still in production. They are in the same 6-ton class as the larger KingAirs. There are a few more twin turboprops in the utility category / light military transport being produced somewhere in the world. This category of aeroplanes is not dead yet!
It may not be dead, but better improve over the 4 turbine setup in the Airbus A400M ;-). Where was that stuck with engine outage lately, Lithuania?

[what next]

Where was that stuck with engine outage lately, Lithuania?Yes. With the German secretary of defense on board. She had to fly home in a 40 year old twin-turboprop Transall... and had that one failed too, she might as well have taken a PC12.

[stilton]

I understand why everyone wants jets but even the light jets must be expensive
to operate and they're not fast, several turboprops leave them behind.

[DirtyProp]

Does anyone other than Beechcraft and Piaggio make twin turboprops anymore ?

There's Vulcanair with the A-Viator:

Vulcan Air (http://www.vulcanair.com/a-viator)

Being non-press I don't think it might be appealing to corporate clients though.

[Gadget freak]

"I'd still take a piston twin, or preferably a twin turboprop over a SET no matter how nice."

How many people have been killed by engine failures in single-engine turboprops?
How many people have been killed practicing engine failures in light twins?

[what next]

How many people have been killed by engine failures in single-engine turboprops?
How many people have been killed practicing engine failures in light twins?

I don't know. Do you? But I guess this Caravan accident alone outnumbers all piston twin training fatalities together: https://aviation-safety.net/database/record.php?id=19850929-0

Anyway, training accidents in twins (which are mostly caused by inexperienced/incompetent instructors) and engine failures in turbine singles have no statistical relation of any kind. Even if we had the figures to derive a statistic from them.

[winkwink]

"But I guess this Caravan accident alone outnumbers all piston twin training fatalities together: https://aviation-safety.net/database...?id=19850929-0"

I suspect not.

[papazulu]

The DHC-6 Twin Otter and the Dornier 228 (now called Do 228 NG and manufactured by RUAG) are still in production.

None of them is pressurized, thus pretty useless for commercial use over the Alps or for specialized roles (i.e. air-ambulance) I guess.

I find the EV-55 (http://http://www.evektor.cz/en/ev-55-outback) a beautiful little thing but...has it gone past the initial flight testing phase and made it into production? Still altitude-limited, tho!

Personal opinion but...in another life I've witnessed serious and demanding commercial-ops flown on PA31s, a/c so tired that my dog would refuse to use them as a canile and still out in the middle of the night, into icing, stuck at FL100 and single-piloted! And all that without mention of the questionable mx practices of some.

So...why are they regarded safer than something like a PC12?

PZ :rolleyes:

[what next]

None of them is pressurized, thus pretty useless for commercial use over the Alps or for specialized roles (i.e. air-ambulance) I guess.

Obviously that leaves enough roles for them to make series production commercially viable (other than the Cessna Conquest, Piper Cheyenne, Mitsubishi Mu2, Rockwell Turbo Commander and whatever other twin turboprops were once built).

I find the EV-55 (http://http://www.evektor.cz/en/ev-55-outback) a beautiful little thing but...

Yes, certainly. And practical as well. Wikipedia knows that only one of them was ever built but does not give the reason for that. Maybe the 200kt cruise speed is one of the factors?

So...why are they regarded safer than something like a PC12?

You compare a type of operation (desperate cowboys flying wrecks through deadly weather) with a type of aeroplane.

I see it differently: If I would operate a piston twin the way I have operated them for more than 2000 hours (including 3 engine failures) I would see my statistical life expectancy higher than if I flew a turbine single for the same number of hours. Because every other risk being the same, an engine (or propeller or prop governor) failure in any single has the potential of killing me. And turbine engines do fail as well (I already experienced one in my 2.500 hours of (twin, luckily) turbine time). My choice stands.

[stilton]

Many of those 'desperate cowboys flying wrecks through deadly weather' are now in the left seat of airline transports spanning the globe.


As a civilian pilot it was the path for me to get the experience needed to move up, most of us didn't have a choice but our professionalism allowed us to survive.


There were very few 'cowboys'

[what next]

Many of those 'desperate cowboys flying wrecks through deadly weather' are now in the left seat of airline transports spanning the globe.

Which is exactly my point: Flying multi engine piston aircraft is not as dangerous as everybody wants to tell us. And therefore quite a few of us who have done it in their time would always prefer it over single engine flying, no matter what kind of engine that is.

[papazulu]

You compare a type of operation (desperate cowboys flying wrecks through deadly weather) with a type of aeroplane.

I never said they were cowboys. As a matter of fact some of these ops are awarded fairly decent contracts but then the requirements narrow down the choice to light-ish twins that can be turned around by a guy or two and then the cash-factor steps in...

Some hairy tales from fellow pilots and my minimal experience of MEPs (another lucky one who logged all his twin-hrs burning Jet A1 here...) suggest me that you can hardly keep altitude after an engine failure in a fully loaded Chieftain that might had been flying into some icing conditions. Surely there is no debate on the single vs. twin's subject once the only donkey has stopped, however THESE (http://http://www.ornge.ca/AboutOrnge/Pages/OurVehicles.aspx) folks seem to be happy to operate modern SETs over high-ground, remote areas, vast expanses of water and into rubbish weather rather than vintage twins.

Many of those 'desperate cowboys flying wrecks through deadly weather' are now in the left seat of airline transports spanning the globe.

Very true, instinct always played the biggest role and the bad apples I met were very few.

[Gadget freak]

"I don't know. Do you? But I guess this Caravan accident alone outnumbers all piston twin training fatalities together: https://aviation-safety.net/database...?id=19850929-0"

and since that was fuel contamination I don't think four engines would have helped.

[SASless]

One Man's opinion....Midnight, VFRon Top in a Caravan, over "The Alps" between Spokane and Olympia in Washington State....Full Moon...beautiful night!

Then...while looking at a couple of really tall, steep, Rocky Mountain tops poking up out of the undercast...instant recognition of just how fatal an engine failure would be!

Loved flying the Caravan....but instantly became a King Air lover!

[Gadget freak]

The accident rates during training for engine failures in piston twins used to be awful although they are much better now - google Dick Collins.....

Has anyone posted the link to the EASA funded QinetiQ report, plenty of stats in there if you are interested.....
http://www.easa.europa.eu/system/files/dfu/Single%20Engine%20Operations%20in%20IMC%20and%20at%20Night%2 0Risk%20Assessment%20Issue%202.pdf


I have to declare an interest. I used to work for Pilatus and always felt comfortable flying in any of their products over the Alps - by day at least.

[rigpiggy]

I love the PT6, but if it doesn't have at least 2 engines.........

[gordon field]

Having been a founding member of the original JAA SEIMC Working Group and attending many but not all meetings in NL I do perhaps have a good insight into the reasoning behind the safety issues.

At the first meeting the UK CAA, German LBA and many other NAAs stated that they were totally opposed to any form of Commercial SET operations as they were deemed to be unsafe. This was before the agenda and ground rules had been discussed. The CAA rep then retired from the Authority but left his stamp on the team. Many of the EU NAAs were scared stiff of the CAA and followed their opinions blindly. The very wise Graham Skillen from the CAA headed their contingent but was bound by instructions from above. We analysed every accident to an SET aircraft to determine whether or not it was engine related, The CAA wanted to classify one 'unexplained' accident as an engine failure until I pointed out that I knew that the pilot had taken his life. The experienced man from the French BEA who wrote the accident report stated that he thought that my comments were closer to the truth than their official report. Some days it was tough battle as many of the officials didn't want to introduce possible liabilities to their NAAs. The late Ronald Ashford ex CAA and JAA was a good Chairman.

At the subsequent meetings with 3 from the CAA we discussed and with difficulty set desired safety targets such as the all cause in flight shut down rates for the PT6 and aimed for a target of not more of 1 engine failure per 6 per million engine hours, the rate is now close to becoming less than 4 per mil. This includes ALL engines not those just maintained to Commercial standards but included engines in 3rd world operations and on extended tbo some up to 8000 Hr and some dodgy engine overhauls. No note was taken of the number of cycles run. As stated the accident with 17 fatalities was caused by water in the fuel it would have happened if the aircraft had 2,3 or 4 engines.

The reliability of the engines cover ALL engines and ALL types of operations, NOT just those maintained to commercial standards. Many of the Caravans are used for bush and para operations and often flown by low time hour building pilots who want turbine time and little or no ground school training. The maintenance standards required and initial and recurrent training for the pilots are much more rigorous than for private operations.

Comparing existing statistics with those likely under the proposed regulations is the equivalent of stating the safety standards of the London Black cabs but including the accident stats from UBER and minicabs. The new regulations are designed to improve the already good safety record, let the public make the decision.

The only engine under consideration was the PT 6 and the only aircraft The TBM 700, Pilatus PC12 and the C208 all of which have an emergency power lever so if there is a failure of the FCU then unlike in a King Air the pilot still has power available. New SET aircraft or modified older aircraft will have to provide safety substantiation for them to be considered for SET commercial operations.

The other criteria was the Fatal Accident rate (all causes). From the statistics available The rate is equal to that of MET aircraft but now trending to be better. The rate for MEP is unknown as the hours are not reported but off airport landings in avgas powered aircraft sadly often involve fire and most do not have a 4 point harness for the pilot. The SET aircraft being designed to later certification standards and having a lower impact and touchdown speed the passengers in SET aircraft are much more likely to survive an off airport landing. The stats confirm this. Sadly many of the pilots who did not survive such landings had failed to fasten their 4 point harnesses.

The QuinetiQ report is badly flawed and was not subjected to interested party comments and peer review as the JAA and the EASA had no experts or peers to review it. The CAA had NO experts in house as they didn't permit such operations so didn't know, they did have some enlightened people but the policy was Not in my backyard still prevailed from the top down? The staff at QuinetiQ did not even bother to accept an invitation to visit a local commercial operator of SET aircraft nor attempt to discover the standards to which the 'Commercial' operators of many PC12s and TBMs operated to I gave them the names of the contacts. Ill spent JAA money for a technically thin but well padded report.

The requirement for always being within 15 minutes out of gliding distance of a suitable landing site was introduced by the CAA when I was not at the meeting. The Spanish had permitted operations from the mainland to the Balearics. The rule was not thoroughly thought through from an operational point of view as in that they state that it can only be used once per flight. They assumed that the engine always gave no warning of failure, seized instantly and that the aircraft was then at best gliding speed. They said that on airways it was illegal to convert the energy you had to altitude and thus increase the distance one could then glide. When ETOPS was introduced there was the 90 min wet footprint rule that traveled with the aircraft along the route, then increased to 180 and I think now 270 min available or more as a continuous risk period. These extensions are based on the proven in service reliability of the engines. There has not been any increase in the risk period for SET aircraft that was set some 10 years ago, yet the hours flown has increased from probably 8 million to over 20. The EROPS risk is now surely not the failure of an engine or systems but the landing at a frozen airport where the aircraft has to be evacuated because of smoke or fire and the life threatening freezing and wind chill conditions for 350+ passengers. You cannot get them to climb back up the slides and most airports don't have heated buses available to transport them to the terminal. The UK CAA introduced this face saving, not life saving proposal 15 minute proposal, but then none of 'their experts' had actually flown a civilian SET and were not aware of commercial SET operations as they were not permitted.

Some 10 years ago there were more SET aircraft operating in Europe than there were piston twins in commercial operations circa 270. These SET aircraft were not falling out of the sky due to engine failures landing on schools or orphanages, no they just got on with their job of safely transporting passengers and freight from A - B in all weathers, just we can see everyday on FR24. The vast majority were flown by private pilots not by commercially trained pilots and nor were the aircraft maintained to the proposed rigorous standards.

Yes there have been accidents and fatalities but if you analyse them in depth you will often discover that the pilot was attempting to operate the aircraft outside of the approval status shown in the limitations section of the approved Flight Manual: Often too high, too fast, not checking that they are pressurised, not de-icing the frosty wings, grossly overloaded, out of C of G. Nothing new there they do the same in twins. If an engine fails on takeoff in in a King Air or a misjudged SE Go around sadly many of us have heard the thump and seen the sickening pall of black smoke. Pilatus have proven that a well trained current pilot suffering an EFATO can if prudent turn back at a height of 750ft. I believe that the TBM has a fatal accident rate due to engine failure of ZERO.

Modern flight information data such as Skydemon and others can show you the gliding distance at any point in flight and importantly in planning the flight. Later aircraft have EFIS with Flight Planning on the IPad.

Will the sky be full of Commercially operated SET aircraft and the older twins gone to the scrap heap? Not in my opinion, the market will find its own level, there will always be the place for light piston twins, cabin class twins as well as SET aircraft. So far as over-water operations are considered a PC 12 was successfully ditched in the Pacific and so have some Caravans for they have big doors. I would not like to be scrambling to escape underwater with 9 others from some of the newer small 9 seat high wing light twins coming on the market. Islanders and Commanders don't ditch well.

Commercial customers demand reliability, goods or people transported from A to B on time on a regular basis often over great distances and if you operate old turbine twins such as Commanders, LET, MU2 and Metros or piston twins such as Aztecs, Navajos or Cessnas then unless you have spare aircraft at least 5 for every 3 needed in service then you will go bust.

Please be open minded about the development of SET operations but unless you have thoroughly evaluated both the aircraft, the equipment, the training required and the proposed regulations please don't shoot from the hip and make unsubstantiated or emotional comments.

[winkwink]

Excellent and thoughtful post.

[gordon field]

Thanks Winkwink.

[megan]

Please be open minded about the development of SET operations but unless you have thoroughly evaluated both the aircraft, the equipment, the training required and the proposed regulations please don't shoot from the hip and make unsubstantiated or emotional comments.Many thanks for that insight Gordon.

I think personally it all gets back to what a person is willing to accept in their perception of risk. Flew thousands of hours over water single engine (Bell 205 with T-53) in my youth knowing that a ditching in the often bad weather we had would result in our demise. Occasionally used to look at the blown spume and give Mr. Lycoming thanks for a solid product, but not something I, or the rest of the pilots, worried about. The only time we had an engine failure, and ditching, was when the engine swallowed part of the FOD screen due fatigue.

Talking to a few young PC-12 pilots engaged in a lot of night work over inhospitable country side say that engine failure is a concern. One was very happy to give up the PC-12 for a job on a King Air with two PT-6 employed in the same role.

Just one question Gordon, why was the failure rate of the PT-6 in twin installations not considered as part of the failure rate? SIL had PT-6 spit the chips, 1,000 hours on brand new airframe and engine just recently, but had another to bring him home (King Air). Think it was a stator let go.

There are additional factors to take into consideration flying IMC in SE. Richard Collins wrote much on the subject, clear air below the cloud base in the event of a failure in order to set up for the forced landing being one he cited. But once again, it's what risk you are willing to accept IMHO. Not everyone enjoys fun park rides, bungee jumping or skydiving. Motorbikes are out for me, though see the attraction.

[gordon field]

Megan the IFSD rate for the PT 6 included those installed in all aircraft both singles and twins and I assume fixed wing only but PW C are reluctant to publicly release data. Many of the shut downs on ME aircraft would not have happened on SET aircraft as these have redundancy built in. PWC do not state. The hr or cycles run on the engines, who overhauled them, when or type of operation.

The Working Group did consider and recognise the increased risk of flying over hostile terrain but left it to market forces to prevail otherwise some could counter that SE training in ME aircraft could be shown to have a higher but as yet unquantifiable risk.

The statistics are based on non commercial operations and hopefully the enhanced initial and recurrent training that is required should reduce fatalities. I believe that a thorough review of a selection of accidents should be part of the training for it clearly highlights what can happen if you deviate from SOP.

[stilton]

What 'redundancy' does a SE turbine have ? if it's failed the only redundancy you have left
is gravity.

[what next]

The QuinetiQ report is badly flawed and was not subjected to interested party comments and peer review as the JAA and the EASA had no experts or peers to review it.

When reading such a statement it would of course be helpful to get a reaction from QuinetiQ as well. And to see the comment QuinetiQ wrote about your report (which, I assume, is not peer reviewed either?).

Anyway, this is all about statistics and obviously the statistics (accompanied by some lobbying work I suppose) have convinced most/all aviation authorities to allow commercial IFR operations of single engine turboprops. So be it.

However, when it comes to actually flying such a thing at night over hostile and deadly ground (like mountains and icy waters) it is no longer a statistic, but a very individual challenge for the pilot who sits at the controls. Some of us can obviously accept the situation, others can't. I only ever had one sleepless night before a flight. That was when I flew commercially on MEPs (which I still consider safer than SETs) and was facing a particularly difficult flight which was on the very limit of everything (range, payload and weather). After successfully completing that flight I promised myself that I would never again fly commercially on a piston aircraft. I still fly them and instruct on them and enjoy it a lot, but no more under the pressure of flying commercially. And I know that I am not the only one. It is an individual and emotional topic.

We are humans, not Vulcans, and therefore not able to completely suppress our emotions. Those emotions can turn the most beautiful job in the world into sleepless nights even if statistics tell my analytical mind (got myself a ph.d. in aerospace engineering in another life) that everything is going to be all right. And as I really enjoy sleeping well, I insist that my employer honors my one and unique life by putting out enough money to pay for a second engine.

[arketip]

And yet, is ok to fly from Spain to Germany in a single with an engine shut down at night, but it become very scary and dangerous to fly a single turbine on the same route?

[megan]

What 'redundancy' does a SE turbine have ?Not putting words in Gordons mouth, but I think he may be referring to some installations which have a manual fuel mode which the pilot can engage and bypass the automatic functions of the FCU. Would be interested to data on the number of occasions that may have occurred. Have a few thousand hours on PT-6 Twin Pac installation and only once engaged manual fuel in anger to control an overspeed. Deemed to have been caused by ice in a air line on the FCU.

[stilton]

That's fine but certain failures cannot be 'bypassed'


You're describing a system redundancy, true powerplant redundancy means you have another one, or more..

[winkwink]

Absolutely. Which is why the statistics make such interesting reading since they show what happens in real life and not what happens in our fears and fantasies of SET and MET or MEP.

[what next]

And yet, is ok to fly from Spain to Germany in a single with an engine shut down at night,...

Not with a single word did I say that this is OK. I wrote about the incident (which in any decent company would have been the last flight of that pilot) to show that the most shaken down piston twin can carry you for another 1000NM if necessary. Like in the middle of a stretch of ocean at night, which is what this whole thread is about.

[gordon field]

What Next. Q were tasked by the by the JAA to write a report, this included The JAA seeking clarification on certain points. Q said to me that they did not have the funding necessary to enable them to visit operators, (35 Miles). They didn't try email. The Q report was included as part of an NPA and many disparaging comments were made by many using the CRD process. These comments can still be read on the EASA website and are openly critical of the findings in the report as they did not take into account as to what was actually happening in the real world and what had been happening in Europe since 1987.

The comments that I have made here and elsewhere were openly discussed at SEIMC Working Group meetings attended by the CAA and other NAAs. None of the committee members were commercial operators as such, nor manufacturers and I was the sole Industry representative as a founder member of ECOGAS (European Council of General Aviation Support). The WG had accident investigators from the BEA and Pilatus and good moderators from the JAA.

I read the comments that you and others make but am not about to enter into a general debate on the subject.

[what next]

Gordon Field: I read the comments that you and others make but am not about to enter into a general debate on the subject.

You don't have to! Thank you for clarifying a few points. Out of interest I visited your website and a few links provided there, where I came across some people who I have met in person and regard as highly qualified professionals.

[gordon field]

What next. Aviation is indeed a very small world and since I started in '57 I have met some wonderful people and am always happy to 'talk' via email.

[Nugget90]

Gordon Field has provided some really interesting background information into the early years of the Single Engine IMC Panel's deliberations, to which I - an experienced transport aeroplane pilot, both military and civil, and for some years a Principal Flight Operations Inspector - might be able to add a perspective from a regulator's (UK CAA) perspective. I was for some 20 years in the Authority's Flight Operations Department and represented such interests first in the JAA Operations Committee and then, after a three-year break, in the successor Sectorial Team. I was therefore involved initially in helping to draft JAR-OPS 1 and 3 (Flight Operations Requirements for Commercial Air Transport Operations by aeroplanes and helicopters), and latterly in revising and updated these documents. SE IMC was a topic that naturally we had to address, not least because there were Single Engine Turbine (SET) aircraft manufacturers in Europe and some aspiring SET Air Operators Certificate applicants. (Readers in the USA might remember that the term used in their documents was 'SE IFR' which of course could include flights made in VMC that the JAA saw no reason to exclude per se from SET CAT. Operating in European skies it might be difficult to ensure that VMC would obtain throughout a planned flight, but that would have to be an operational/business decision for any aspiring SET CAT operator.)

First, I call to mind that our SE IMC deliberations by the JAA Operations Committee were confined to Commercial Air Transport (CAT) operations. These have always commanded higher levels of safety for the aircraft, its occupants and the wellbeing of third parties on the ground than need to be applied to aircraft intended to be used for General Aviation (GA). By this I mean purposes such as are described in ICAO Annex 6, i.e. aircraft used for purposes other than CAT. The topic addressed in this forum, as commented upon in post 42 above, might just as well have been conducted under a CAT heading.

The design and certification of aircraft designed for CAT purposes generally incorporate higher levels of redundancy and risk mitigation than are required in aircraft used for other purposes, which is why a proposed single-engine CAT operation was always bound to deserve very careful consideration. I have no doubt whatsoever that SET aeroplanes of today together with improvements made in the past 20 years (when CAT SE IMC was first being considered in Europe) have resulted in far more reliable power plants than hitherto. Taken in conjunction with appropriate incipient failure alerting devices and frequent inspection regimes, the modern turbo-propeller engine exhibits many advantages that a piston engine cannot match.

Yet power plant reliability was only one of the issues that had to be considered. In the JAA Ops Committee we had to think of what the pilot would need to do when the engine failed - i.e. stand a reasonable chance of alighting where the aircraft would not suffer significant damage thereby allowing all on board to leave it without injury. Our concern was that the pilot needed to be able to know where he/she might aim to land and see all that would be required to manoeuvre so as to achieve this successfully. Hence the 'IMC' part of the equation. Whilst there need be no restraints on operating where the flight remained clear of cloud, mist, fog etc in daylight, the problem was how to navigate when the visibility prevented appropriate positioning to land where desired. In the mid/late 1990s the navigation systems then available could not provide suitable guidance to acceptable landing sites, and enhanced visual guidance systems didn't exist. The Ops Committee was especially concerned that flights made over the densely populated towns and cities of Europe posed a risk to those third parties on the ground I mentioned earlier in addition to the risk of injury or death to pilots and their passengers.

It was in part due to these and other issues articulated by the Ops Committee that the SET manufacturers were encouraged to find solutions that have now persuaded EASA to prescribe regulations under which SET CAT operations may take place: tough requirements introduce risk mitigations that acknowledge the absence of redundancy if/when the single engine fails, and operational constraints improve the chances that the pilot(s) may expect to be able to glide to a place where a (relatively) safe forced landing may stand every chance that the occupants will not suffer injuries and third parties, both people and property on the ground, will not be impacted.

In the early noughties I became the UK representative on the newly-constituted ICAO Operations Panel and assisted them for just under three years, where of course this topic was one of many we discussed. Our view then, as it had been in the JAA Operations Sectorial Team, was not to say 'No' to CAT SE IMC but to press for improvements in the design, certification and maintenance of SET power-plant/airframe standards together with improvements in aircraft navigation equipment and pilot training - all of which I understand have now been put in place.

SET aeroplanes have established themselves as vital to the support of life and livelihoods across the globe, mainly of course where the weather is benign and suitable landing sites can easily be acquired, and now - provided modern standards deliver the levels of reliability that are sought - we might reasonably expect the current generation of SET aircraft to become more visible in European skies.

I hope that this helps to inform readers who are interested in this topic as to why regulatory approval to operate CAT SE IMC has taken so long to merit support from the European Authorities, both before and after EASA was established.

[gordon field]

Thank you Nugget for a very balanced and informative post.
I did find that many within the NAAs and JAA/EASA did not take into account the considerable number of privately operated SET aircraft that were actually safely operating within 'EASA airspace' on a regular day to day basis. This includes a considerable number of Piper Jet prop aircraft that have been modified by replacing the piston engine with a PT6.
There were and still are some very good operators who operate to the proposed regulations but also many privately owned aircraft aircraft where once the pilot had been issued with his 'Type Rating' (not required for the C208) then they were left to really set their own standards for recurrent training.

Yes there have been some accidents to SET aircraft in Europe but in general these have not been caused by the loss of thrust but more likely by flying the aircraft outside of its permitted limits.

The changes in the way that the winds aloft, glide distance, traffic/terrain mapping, and weather data and programmed landing sites is now available to the pilot will further increase safety.

The requirement that the pilot can (should) only use the 15 minute risk period once per flight is clearly nonsense and is not in accordance with the ICAO SARP as the potential for loss of thrust in the cruise sector is significantly less than during the climb out.

I just hope that there are still a sufficient number of experienced Operations Inspectors employed by the NAA to deal with the applications in a timely manner.

[brazeagle]

Hello all,
Anyone could help with finding any research on PROS & CONS, accident rates, etc on Single Engine Turbo Prop vs Multi-Engine Turbo Props?

Thanks in advance.
LCL

[Pace]

Reliability on many piston engines is largely affected by maintenance and pilots. Turbines are seeing professional handling and pilots in most cases. The engines are not guilty if the owner doesn't care and the pilot doesn't either.

I knew pilots of a twin turboprop Commander who took a large bird through the prop
They had to shut that side down
Single Turboprop over heavy seas at night ?
You at least owe it to the PAX to well inform the PAX of those risks

[AdamFrisch]

I don't think there's statistics for SETP vs METP. It's also impossible to get reliable data in any single vs twin debate, because every time a twin shuts one down and continues to destination, it doesn't end up in any statistic. Only way to get reliable data was if every flight gets somehow logged centrally, which will never happen.

[Pace]

BrazeEagle

A lot of flying is always about plan B or even C
Best advice I was ever given was to never do anything where there are no alternative options otherwise it's a game of Russian roulette

Turbo props maybe very reliable and engine out unlikely but having had some very unlikely occurrences in the past a single Turboprop over long stretches of water at night is a crazy risk to take
Alone it's your risk! With unknowing passengers your taking that risk decision for them
I had a client who was flying to Denmark in a TBM
I advised him to go in the day and take a longer route around the coast
You can have all the statistics in the world
If life is cruel to you you have no realistic options should that engine stop for whatever reason
I sometimes fail to understand owners who will cough up $5 million for a single PC12
Take a huge hit in depreciation to save a bit on fuel and maintenance

The same with those who get a private jet! Pay for two engines dual systems but have one heart at the controls

[barit1]

https://en.wikipedia.org/wiki/Max_Conrad