Single turboprop commercial IFR
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I will not enter the debate as to single engine air transport ops.
However, I would comment that something is going very, very wrong somewhere for the failures reported here to be occurring with such frequency.
However, I would comment that something is going very, very wrong somewhere for the failures reported here to be occurring with such frequency.
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One of the problems here is IFR. A small aircraft such as the Caravan or PC-12 can usually find somewhere for an emergency landing in VMC, even a city street. This is fine until IMC conditions leave you with little chance to find a safe spot.
Another issue is the typical operator of such small operations, like it or not their aircraft are not going to be maintained quite as scrupulously as someone like Fedex with a large fleet.
Is there really a market in the UK ?. IFR operations implies routes between properly equiped airports. Is there really a market for scheduled 12 seat operations between major airports with ILS etc or are we talking about ad hoc charters and other GA calling IFR when the weather gets wormy en route.
Another issue is the typical operator of such small operations, like it or not their aircraft are not going to be maintained quite as scrupulously as someone like Fedex with a large fleet.
Is there really a market in the UK ?. IFR operations implies routes between properly equiped airports. Is there really a market for scheduled 12 seat operations between major airports with ILS etc or are we talking about ad hoc charters and other GA calling IFR when the weather gets wormy en route.
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The irony is that the experiences in Canada and US have shown that collectively single-engine turbopros are -- statistically speaking -- as safe or safer than twin turboprops.
See for example the annual reports on turboprop safety from Breiling & Associates. Every year single-engine turboprops have accident rates (and fatal accident rates) comparable to, or better than, turboprop twins.
In Europe, single-engine commercial IFR is already a reality in a number of countries (France, Spain, Sweden, Finland, Norway, etc.) operating under EASA exemptions.
What's being proposed is to harmonize the rules EU-wide. I believe the new rules will come into effect in 2016.
See for example the annual reports on turboprop safety from Breiling & Associates. Every year single-engine turboprops have accident rates (and fatal accident rates) comparable to, or better than, turboprop twins.
In Europe, single-engine commercial IFR is already a reality in a number of countries (France, Spain, Sweden, Finland, Norway, etc.) operating under EASA exemptions.
What's being proposed is to harmonize the rules EU-wide. I believe the new rules will come into effect in 2016.
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To continue the statistical line, 51,000 or so PT6 engines have been built in 50 years. Let's assume (complete guess) that 20% have been scrapped, and that 70% are on an aircraft, with 10% in overhaul, or in the spare engines cupboard.
So that's 35,700 on an aircraft. Many of those are corporate, private even, and fly very few hours. Others will be busier. My absolute guess is that the average hours per day is 2.
If that's anywhere near right, those engines will fly 75,000 hours a day, so using Peekay4's data we can expect an IFSD on a PT6 every 1.67 days, somewhere in the world.
Bit of a guess, really, but you get the point. How many would occur in the UK depends on the UK's share of those PT6 hours.
I would have thought that the only really useful IFSD data would be variant-specific; apart from the basic concept there doesn't seem to be much in common between the early ones and the latest, most powerful versions.
Someone did comment that the causal factor there is that pilots are a damn sight more careful about loads, conditions, etc etc with only the one donk in front; the inference being that accidents in twins mostly occur as a result of loss of thrust on one engine. Let's not forget the BN2A Islander, in a similar context. And, of course, that you are twice as likely to experience that loss if there are two engines.
I know, I know, but it's Sunday afternoon and statistical howlers are permitted.
So that's 35,700 on an aircraft. Many of those are corporate, private even, and fly very few hours. Others will be busier. My absolute guess is that the average hours per day is 2.
If that's anywhere near right, those engines will fly 75,000 hours a day, so using Peekay4's data we can expect an IFSD on a PT6 every 1.67 days, somewhere in the world.
Bit of a guess, really, but you get the point. How many would occur in the UK depends on the UK's share of those PT6 hours.
I would have thought that the only really useful IFSD data would be variant-specific; apart from the basic concept there doesn't seem to be much in common between the early ones and the latest, most powerful versions.
experiences in Canada and US have shown that collectively single-engine turbopros are -- statistically speaking -- as safe or safer than twin turboprops
I know, I know, but it's Sunday afternoon and statistical howlers are permitted.
Last edited by Capot; 5th Oct 2014 at 16:03.
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Somewhat puzzled as to why this topic was removed from Rumours and News to Questions. It is an important safety issue and needs the widest possible circualtion. Most people I know ( including me) have never used 'Questions '. I had to do a search to find the topic again.
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EASA NPA 2014-18 Commercial air transportation aeroplane operations at night or in IMC using single engine turboprop aeroplane is the document you should read. Comments are due by 17 Oct 2014. It's on their website.
The relevant safety cases are fully explored with very detailed information on engine reliability.
What is an anomaly is that they propose a risk period of 15 minutes when the aircraft is not within gliding distance of a suitable landing site and that this 15 minutes can only be used ONCE per flight. To my knowledge risk periods such as originally proposed for ETOPS have been on a continuous basis, not just on one occasion.
The engine reliability data does not take into account the cycles/hours and quality of overhaul on any of the engines that have failed.
All of the aircraft have, unlike MET aircraft, an emergency power lever.
What the NPA does not list are the hundreds of SET aircraft that have been regularly flying in the EU for many years at night and in IMC, naturally privately of course. How many of these have fallen out of the sky due to failure of the powerplant or systems?
Having listed and explored all of the reported accidents to SET aircraft around the world the statistics show that it is still the lack of pilot's adherence to mandatory and recommended procedures that results in the majority of accidents and fatalities.
I hope that you will read and digest the information given and comment as you see fit. Don't shoot from the hip otherwise your comments will not be taken seriously.
The relevant safety cases are fully explored with very detailed information on engine reliability.
What is an anomaly is that they propose a risk period of 15 minutes when the aircraft is not within gliding distance of a suitable landing site and that this 15 minutes can only be used ONCE per flight. To my knowledge risk periods such as originally proposed for ETOPS have been on a continuous basis, not just on one occasion.
The engine reliability data does not take into account the cycles/hours and quality of overhaul on any of the engines that have failed.
All of the aircraft have, unlike MET aircraft, an emergency power lever.
What the NPA does not list are the hundreds of SET aircraft that have been regularly flying in the EU for many years at night and in IMC, naturally privately of course. How many of these have fallen out of the sky due to failure of the powerplant or systems?
Having listed and explored all of the reported accidents to SET aircraft around the world the statistics show that it is still the lack of pilot's adherence to mandatory and recommended procedures that results in the majority of accidents and fatalities.
I hope that you will read and digest the information given and comment as you see fit. Don't shoot from the hip otherwise your comments will not be taken seriously.
I think there are two different mindsets in this debate. One is
The other is "Get rid of this gov't Health and Safety crap and let us decide for ourselves what we're willing to risk."
I'm not a shrink, but I suspect that both positions are based deep in the psyche, and neither will be easily swayed by mere facts.
Once again, safety takes a back seat to cost and convenience...
I'm not a shrink, but I suspect that both positions are based deep in the psyche, and neither will be easily swayed by mere facts.
