IFR take-off minima for light twins?
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Peter
This might surprise you but I find the Citation is easier to fly than a Seneca twin and a Kingair : )
Speed is relative but the Citation makes things easier for you in a lot of circumstances ; )
You would find one a doddle to fly! I can get a Citation from cold ready for takeoff within five minutes you won't do that with the TB or the Kingair or a Seneca ; )
Pace
This might surprise you but I find the Citation is easier to fly than a Seneca twin and a Kingair : )
Speed is relative but the Citation makes things easier for you in a lot of circumstances ; )
You would find one a doddle to fly! I can get a Citation from cold ready for takeoff within five minutes you won't do that with the TB or the Kingair or a Seneca ; )
Pace
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Money aside, I would still choose a TBM over any piston twin.
I've done a fair bit of IFR flying around Europe and my view now is that just having a "tank" capable of boring a hole through any weather, simply because it has boots and heated props and a heated front window panel, and hopefully radar as well, is not the way forward.
The way forward is to fly high up, above most "organised" IMC.
Pistons can do that - any half decent turbo job can do FL240 - but you are rapidly into fairly inconvenient (for passengers, anyway) oxygen arrangements, so this leads to pressurisation, and there are very few options for that. The PA46 is the only one currently in production, the other pressurised singles are all variously old wrecks, and pressurised piston twins are also all finished (Baron maybe?).
That's why a piston twin would not feature on my list. Not because I would have to re-do all my paperwork, which I would, but because - short of a 421 type plane which guzzles avgas by the barrel - it would not deliver pleasant flights.
This summer has exposed this stuff more than any I remember. FL200 in a TB20 is right at the very top of what is possible. Yet this is as much as any non-turbo twin will do.
The real way forward in mission capability is not a 2nd motor, but pressurisation and a FL250+ ceiling, and radar.
That's why the only meaningful upgrade from say a TB20 is a Jetprop ($1.2M for a reasonable one), not a Seneca or similar, and not even a turbo Seneca.
Statistically, a single PT6 engined plane is much less likely to go down than a piston twin. Emotionally, this is hard to swallow, and impossible to swallow for the regulators (who demand 2 motors for PT, yet ban a single PT6 for the same job), but the numbers are very hard to argue with.
I've done a fair bit of IFR flying around Europe and my view now is that just having a "tank" capable of boring a hole through any weather, simply because it has boots and heated props and a heated front window panel, and hopefully radar as well, is not the way forward.
The way forward is to fly high up, above most "organised" IMC.
Pistons can do that - any half decent turbo job can do FL240 - but you are rapidly into fairly inconvenient (for passengers, anyway) oxygen arrangements, so this leads to pressurisation, and there are very few options for that. The PA46 is the only one currently in production, the other pressurised singles are all variously old wrecks, and pressurised piston twins are also all finished (Baron maybe?).
That's why a piston twin would not feature on my list. Not because I would have to re-do all my paperwork, which I would, but because - short of a 421 type plane which guzzles avgas by the barrel - it would not deliver pleasant flights.
This summer has exposed this stuff more than any I remember. FL200 in a TB20 is right at the very top of what is possible. Yet this is as much as any non-turbo twin will do.
The real way forward in mission capability is not a 2nd motor, but pressurisation and a FL250+ ceiling, and radar.
That's why the only meaningful upgrade from say a TB20 is a Jetprop ($1.2M for a reasonable one), not a Seneca or similar, and not even a turbo Seneca.
Statistically, a single PT6 engined plane is much less likely to go down than a piston twin. Emotionally, this is hard to swallow, and impossible to swallow for the regulators (who demand 2 motors for PT, yet ban a single PT6 for the same job), but the numbers are very hard to argue with.
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Peter
I'm sure adding a multi to your licenses would be a very simple and cheap thing.
If you did, you could be travelling in what you say is the kind of plane you require for your missions. For $300K you could be in a MU-2 tomorrow that burns only marginally more than a turbine single. Fuel consumption follows SFC and horsepower, therefore a twin never burns much more than a single with equivalent horsepower. Also, the Garretts are more fuel efficient than the PT6s. The MU-2 does 300kts, FL300 with all the mod cons. That would be twice as safe as a TBM850 and would leave you $1million to spend on fuel.
Or a Conquest or Turbine Commander. But the MU-2 is the most bang for the buck. Well supported as well. And if you've ever been close to one, you know how well built they are. No oil canning panels there...
I'm sure adding a multi to your licenses would be a very simple and cheap thing.
If you did, you could be travelling in what you say is the kind of plane you require for your missions. For $300K you could be in a MU-2 tomorrow that burns only marginally more than a turbine single. Fuel consumption follows SFC and horsepower, therefore a twin never burns much more than a single with equivalent horsepower. Also, the Garretts are more fuel efficient than the PT6s. The MU-2 does 300kts, FL300 with all the mod cons. That would be twice as safe as a TBM850 and would leave you $1million to spend on fuel.
Or a Conquest or Turbine Commander. But the MU-2 is the most bang for the buck. Well supported as well. And if you've ever been close to one, you know how well built they are. No oil canning panels there...
Cut & Paste Intellectual
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Unfortunately - you sometimes have to climb up through "organised IMC" and descend. 
I believe the low pressure system currently over the UK is 7 miles thick.
Ain't that the truth.
I believe the low pressure system currently over the UK is 7 miles thick.
I think what has changed is that piston twins cost even more than they used to
They guzzle fuel like it was going out of fashion, they cost a lot more to maintain
They guzzle fuel like it was going out of fashion, they cost a lot more to maintain
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you sometimes have to climb up through "organised IMC" and descend
There is where you need the equipment.
But one needs a better solution for the enroute part. Radar (or a stormscope) won't protect you from some pretty nasty turbulence.
Cut & Paste Intellectual
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At FL250 you can be just in the really turbulent outer edges (isotachs) of the jet stream. Difficult to see and a interesting ride if you encounter this phenomena.
I have driven TBM700 after viewing one at Farnborough and the guys from Tarbes would not let me go unless I had had a test flight. Competent aircraft although the model behind your excellent report and given a million dollars an excellent choice.
My instructor at Humberside drove King Airs and MU2's professionally before and after his training business and he was a very wise old bird with 25000+ corporate hours. The MU2 was his weapon of choice but with that wing - you had to be super current. Just to emphasise the attention to detail - he ferried one from USA and the wrong grease was used in the gear that froze up en route. Slightly nervous approach into Reykavik with 0 greens. There are so many aspects one has to consider with HP a/c at high altitude.
Sorry for the drift Above the Clouds.
I have driven TBM700 after viewing one at Farnborough and the guys from Tarbes would not let me go unless I had had a test flight. Competent aircraft although the model behind your excellent report and given a million dollars an excellent choice.
My instructor at Humberside drove King Airs and MU2's professionally before and after his training business and he was a very wise old bird with 25000+ corporate hours. The MU2 was his weapon of choice but with that wing - you had to be super current. Just to emphasise the attention to detail - he ferried one from USA and the wrong grease was used in the gear that froze up en route. Slightly nervous approach into Reykavik with 0 greens. There are so many aspects one has to consider with HP a/c at high altitude.
Sorry for the drift Above the Clouds.
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the wrong grease was used in the gear that froze up en route.
That issue is actually quite common. I know of a Citation which froze in the climb and was thus flown all the way to Spain with a suitcase jammed between a man in the RHS and the yoke, for a few hours
He was lucky he had someone else around to insert and remove the suitcase.
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Peter
On a black winter night taking off and flying over extensive fog banks in the black below I dont care what the stats say or dont say I like a second power unit
Regarding flying over weather you really need to get up to FL370 FL380 to get on top.
I have met extensive Walls of CBS down near Biarritz and around the Alps as well as over Croatia where a Turbo Prop would not have hacked it!
TBM is a great machine but very interesting is Eclipse which is turning out into a good machine under Sikorski ownership should get in and out of 800 meter strips climb to FL410 and sips fuel!
Range and payload not bad either.
Pace
On a black winter night taking off and flying over extensive fog banks in the black below I dont care what the stats say or dont say I like a second power unit
Regarding flying over weather you really need to get up to FL370 FL380 to get on top.
I have met extensive Walls of CBS down near Biarritz and around the Alps as well as over Croatia where a Turbo Prop would not have hacked it!
TBM is a great machine but very interesting is Eclipse which is turning out into a good machine under Sikorski ownership should get in and out of 800 meter strips climb to FL410 and sips fuel!
Range and payload not bad either.
Pace
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UL730
Sorry for the drift Above the Clouds.
No problem, the old piston twin is an interesting debate, something that gets lots of people hot under the collar, I don't think about it much these days as I operate with 3 very reliable jets engines but have done my fair share of piston twin operations worldwide over the years.
Sorry for the drift Above the Clouds.
No problem, the old piston twin is an interesting debate, something that gets lots of people hot under the collar, I don't think about it much these days as I operate with 3 very reliable jets engines
but have done my fair share of piston twin operations worldwide over the years.
Last edited by Above The Clouds; 24th Sep 2012 at 19:49.
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my take-off minima for private operations with my Seneca II:
200 ft ceiling and 400 m visibility on a runway at least 4000 ft / 1,200 m long, 100 ft wide, ILS, flat terrain around, near MSL, 20 ° C, at 2,000 kg / 4,400 lbs. Things change a lot with terrain, density altitude and mass.
Clean-up (gear, flaps, vyse) as soon as possible;
if an engine fails when cleaned up and the runway is very long - lets say 8,000 ft, even being at 300 ft in the clouds I'd always close the throttles, gear down again, flaps when runway in sight, and land. At low visibility ILS is always set to HSI 1 initially.
I've simulated single engine go-arounds and stuff like that at a safe altitude (4,000 ft above the ground, one engine shut down completely). If the aircraft is well maintained, the second engine will bring you to the next airport safely. I recorded climb rates at 250 kg below MTOM, 6,000 ft DA, that were identical to a Cessna 150 at MTOM at the same altitude. So it's not a glider. At this altitude, 65 % on one engine gave me 94 KIAS (vyse + 5 kts) at 10.5 GPH. A lot of endurance available (I had 110 GAL in the tanks) to think over all options and not even challenging to fly for a properly trained pilot.
When being in hard IFR, over water, at night or during the winter time, I just want to have that second power plant, like said before. Even on a PT6, the prop or its governor could fail. What is true: too many twin accidents occur because of wrong emergency procedures, leck of trouble-shooting and the wrong choice after an engine failure close to ground. Better close the throttles and overshoot the runway in the unlikely event of an engine failure short after lift-off.
Emergency landing in a turbine powered causes much higher speeds and thus risks compared to C172, although the event is rather unlikely. But one day production failures might affect even a PT6, and if it is only due to a supplied part, the fuel system or the prop.
With both engines running, a twin offers a much steeper angle of climb than most singles, which adds safety.
A sudden total engine failure is not the normal case. In many cases, power on the affected engine can be reduced before things get worse (e.g. loss of oil) or partial power is still available (loss of one magneto). I've experienced both of this. The oil leak in C303; at least I could see the oil running out of the engine, because the engine wasn't in front of me; reduced power to idle, landed uneventful 30 min later, still 3 qts in the engine which survived (the leak was easy to fix).
To reduce the risk of an engine failure due to high engine load and especially right after departure, I maintain below max. MP during take-off on long runways (e.g. 38" instead of 40") and reduce to 75 % at 300 ft AGL.
I regularly do fly without the aid of the autopilot in solid IMC, practice crosswind landings, approaches in low IMC and emergency procedures. The redundancy of all the instruments and power sources (gyro air, electrics) is another important benefit. However, the pilot must be able to cross-check all these redundant instruments during an approach to minimums. Adequate cross-checking (altimeters, both LOC + GS) is trained rarely, unfortunately. Many instructors and examiners even don't want to put both HSIs / NAVs on the ILS, but the second one already for the missed approach.
These are just my thoughts about flying safely in marginal weather.
Best regards,
Andi
200 ft ceiling and 400 m visibility on a runway at least 4000 ft / 1,200 m long, 100 ft wide, ILS, flat terrain around, near MSL, 20 ° C, at 2,000 kg / 4,400 lbs. Things change a lot with terrain, density altitude and mass.
Clean-up (gear, flaps, vyse) as soon as possible;
if an engine fails when cleaned up and the runway is very long - lets say 8,000 ft, even being at 300 ft in the clouds I'd always close the throttles, gear down again, flaps when runway in sight, and land. At low visibility ILS is always set to HSI 1 initially.
I've simulated single engine go-arounds and stuff like that at a safe altitude (4,000 ft above the ground, one engine shut down completely). If the aircraft is well maintained, the second engine will bring you to the next airport safely. I recorded climb rates at 250 kg below MTOM, 6,000 ft DA, that were identical to a Cessna 150 at MTOM at the same altitude. So it's not a glider. At this altitude, 65 % on one engine gave me 94 KIAS (vyse + 5 kts) at 10.5 GPH. A lot of endurance available (I had 110 GAL in the tanks) to think over all options and not even challenging to fly for a properly trained pilot.
When being in hard IFR, over water, at night or during the winter time, I just want to have that second power plant, like said before. Even on a PT6, the prop or its governor could fail. What is true: too many twin accidents occur because of wrong emergency procedures, leck of trouble-shooting and the wrong choice after an engine failure close to ground. Better close the throttles and overshoot the runway in the unlikely event of an engine failure short after lift-off.
Emergency landing in a turbine powered causes much higher speeds and thus risks compared to C172, although the event is rather unlikely. But one day production failures might affect even a PT6, and if it is only due to a supplied part, the fuel system or the prop.
With both engines running, a twin offers a much steeper angle of climb than most singles, which adds safety.
A sudden total engine failure is not the normal case. In many cases, power on the affected engine can be reduced before things get worse (e.g. loss of oil) or partial power is still available (loss of one magneto). I've experienced both of this. The oil leak in C303; at least I could see the oil running out of the engine, because the engine wasn't in front of me; reduced power to idle, landed uneventful 30 min later, still 3 qts in the engine which survived (the leak was easy to fix).
To reduce the risk of an engine failure due to high engine load and especially right after departure, I maintain below max. MP during take-off on long runways (e.g. 38" instead of 40") and reduce to 75 % at 300 ft AGL.
I regularly do fly without the aid of the autopilot in solid IMC, practice crosswind landings, approaches in low IMC and emergency procedures. The redundancy of all the instruments and power sources (gyro air, electrics) is another important benefit. However, the pilot must be able to cross-check all these redundant instruments during an approach to minimums. Adequate cross-checking (altimeters, both LOC + GS) is trained rarely, unfortunately. Many instructors and examiners even don't want to put both HSIs / NAVs on the ILS, but the second one already for the missed approach.
These are just my thoughts about flying safely in marginal weather.
Best regards,
Andi
Last edited by AndiKunzi; 6th Oct 2012 at 21:35.
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I think there is a lot of nonsense talked about light twins personally 
The accident rates are far BETTER than a light single - go check the NTSB website and see for your self. If you look at twin accidents, the accident rate is far less but the fatality rate is higher. Most of the accidents seem to be CFIT type accidents and not aeroplane failure accidents or "loss of control". They are more of a handful but then again someone who regularly flies a twin will be a more experienced pilot (in general), probably explaining the low "loss of control" type of accidents.
Secondly, in all the light twins I have flown, I have always been able to climb single engine. True I have probably been below MAUW, but that is how I mostly fly a Twin anyway - 3 or 4 of us for a weekend. Even a dodgey old Seneca II has a single engine service ceiling of 13000' and it will readily climb up there. I failed an engine on a DA42 at 6000' over California with 3 POB and plenty of fuel and we were climbing quite happily with no drama. As many instructors say, it is quite boring, and boring when flying is a good thing unless you are doing aeros
But back to the OP's question - what do you feel safe in? I took off out of Edinburgh in a Single in 600m RVR and 200' OC and rain. I had the GPS on showing me the Forth in case we had to ditch but I didn't feel particularly worried. At 4000' we were on top in glorious sunshine (apart from the Cbs towering around us but that is another story!).
My buddy who flies bizjets is very loathed to even cross the channel in a SEP these days - maybe with age and experience your fear increases, which is why in the USA when flying around California / Nevada and the hostile terrain there I now nearly always rent a twin !
The accident rates are far BETTER than a light single - go check the NTSB website and see for your self. If you look at twin accidents, the accident rate is far less but the fatality rate is higher. Most of the accidents seem to be CFIT type accidents and not aeroplane failure accidents or "loss of control". They are more of a handful but then again someone who regularly flies a twin will be a more experienced pilot (in general), probably explaining the low "loss of control" type of accidents.Secondly, in all the light twins I have flown, I have always been able to climb single engine. True I have probably been below MAUW, but that is how I mostly fly a Twin anyway - 3 or 4 of us for a weekend. Even a dodgey old Seneca II has a single engine service ceiling of 13000' and it will readily climb up there. I failed an engine on a DA42 at 6000' over California with 3 POB and plenty of fuel and we were climbing quite happily with no drama. As many instructors say, it is quite boring, and boring when flying is a good thing unless you are doing aeros
But back to the OP's question - what do you feel safe in? I took off out of Edinburgh in a Single in 600m RVR and 200' OC and rain. I had the GPS on showing me the Forth in case we had to ditch but I didn't feel particularly worried. At 4000' we were on top in glorious sunshine (apart from the Cbs towering around us but that is another story!).
My buddy who flies bizjets is very loathed to even cross the channel in a SEP these days - maybe with age and experience your fear increases, which is why in the USA when flying around California / Nevada and the hostile terrain there I now nearly always rent a twin !
