King Air Runup - In Reality
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Daniel I am going to need you to post up the no AF numbers vs installed numbers out of the same flight manual to prove that it changes VMC. I am not doubting on certain aircraft that might be the case, but this is the first time I am have heard that mentioned and it's definately outside of 'what makes sense'.
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TELDOSERIOUS,
refer to P180 AFM, Sect 2 Limitations, Pag 2-3
VMCa AF System Operating : 100 KIAS
VMCa AF System Not Operating (propeller windmilling) : 128 KIAS
The difference is due to the fact that, with AF not operating, there is such a huge drag from the windmilling propeller that VMCa is to be increased by approx 30 KIAS, this make a lot of sense to me.
Not all the a/c shows this difference in limitations with and without AF.
Attempting a TO on the assumption that the AF system is working, if in fact it is not working, will end in a dysaster if one engine fails at a TO speed schedule which is 30 KIAS lower than the minimum reuqired.
refer to P180 AFM, Sect 2 Limitations, Pag 2-3
VMCa AF System Operating : 100 KIAS
VMCa AF System Not Operating (propeller windmilling) : 128 KIAS
The difference is due to the fact that, with AF not operating, there is such a huge drag from the windmilling propeller that VMCa is to be increased by approx 30 KIAS, this make a lot of sense to me.
Not all the a/c shows this difference in limitations with and without AF.
Attempting a TO on the assumption that the AF system is working, if in fact it is not working, will end in a dysaster if one engine fails at a TO speed schedule which is 30 KIAS lower than the minimum reuqired.
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Daniel,
Thanks, can you post up those pages? I don't have a Piaggio manual. I am curious is the AF an install option on that aircraft, is the pilot allowed to fly installed but non operational? Also, what are the single engine unfeathered climb numbers on that aircraft. From what you are saying it sounds like the OEM is giving you a new VMCA only in the event that it fails, not as an option do depart with a working AF or not.
All that said the Piaggio has less asymetrical thrust issues then other aircraft so it would be fascinating to think that this aircraft is even flyable unfeathered where in a conventional aircraft it's a disaster.
I am just curious because on some other aircraft with an AF installed, there was no install option, nor any choice to fly with out it being operational, that as you touched upon, the reason was the unfeathered profile was so disastrous that it was actually a negative climb rate at VMCA.
Thanks, can you post up those pages? I don't have a Piaggio manual. I am curious is the AF an install option on that aircraft, is the pilot allowed to fly installed but non operational? Also, what are the single engine unfeathered climb numbers on that aircraft. From what you are saying it sounds like the OEM is giving you a new VMCA only in the event that it fails, not as an option do depart with a working AF or not.
All that said the Piaggio has less asymetrical thrust issues then other aircraft so it would be fascinating to think that this aircraft is even flyable unfeathered where in a conventional aircraft it's a disaster.
I am just curious because on some other aircraft with an AF installed, there was no install option, nor any choice to fly with out it being operational, that as you touched upon, the reason was the unfeathered profile was so disastrous that it was actually a negative climb rate at VMCA.
Last edited by Teldorserious; 25th May 2013 at 14:09.
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Teldorserious
... I am still trying to find out how to attach files, since it seems that I am not eligible to do that ("you may not attach files" itr says....)
Danioel
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I am just curious because on some other aircraft with an AF installed, there
was no install option, nor any choice to fly with out it being operational, that
as you touched upon, the reason was the unfeathered profile was so disastrous
that it was actually a negative climb rate at VMCA.
My understanding is that on certain KA models, Beech (or Raisbeck) wanted to take advantage of the lower Vmca available from AF and asked the FAA to accept a Vmca when feathered (rather than the windmilling standard) if AF was fitted. That made the AF a required item both for certification and operationally (since they didn't publish "No AF" performance). However there were 4 blade KA models that didn't require AF, had different low pitch mechanisms I think.
Don't take my word for it, it's in Tom Clements' King Air book, from p205.
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421c - Right, except you won't find the unfeathered numbers on a Conquest I, which was my introduction to the AF. When I asked, and asked, turns out the unpublished numbers are so horrible that the AF is required, so much so, the manufacturer took feathering the prop completely out of the hands of the pilot.
Whether the AF is optional on the King Air or P180 is certainly possible if it was installed as a pilot helper, a safety enhancer because on those aircraft an unfeathered prop is not the end of the world.
What AF really does is immediately feather the prop, and the right one, where pilots take some time to figure it out, as feathering the wrong one has killed people, and since I teach this stuff, it's one of those, 'better get this one right type of things'. So if VMCA is higher on say a Piaggio, with out the AF, that tells me they are trying to keep the pilots at a safe speed unfeathered, until they can get the prop feathered. In the Conquest there is no unfeathered VMCA, where I assume it doesn't exist, it's that bad.
The point being is that if the xlist says to check the AF, yeah you better check it, or your are playing test pilot.
Whether the AF is optional on the King Air or P180 is certainly possible if it was installed as a pilot helper, a safety enhancer because on those aircraft an unfeathered prop is not the end of the world.
What AF really does is immediately feather the prop, and the right one, where pilots take some time to figure it out, as feathering the wrong one has killed people, and since I teach this stuff, it's one of those, 'better get this one right type of things'. So if VMCA is higher on say a Piaggio, with out the AF, that tells me they are trying to keep the pilots at a safe speed unfeathered, until they can get the prop feathered. In the Conquest there is no unfeathered VMCA, where I assume it doesn't exist, it's that bad.
The point being is that if the xlist says to check the AF, yeah you better check it, or your are playing test pilot.
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Teldorserious,
since I am unable to upload attachments (I am waiting suggestions from the Administrator)
I copy herebelow the relevant parts of the AFM (you can anyway download it from different websites)
Rev.0 Issued 21-oct-2005
Pag.2-2
Minimum control speed
Autofeather system operative 100 KIAS
Propeller windmilling 128 KIAS
Engine failure in flight below Vmca
Pag 3-6
1 Power lever (operating engine) Reduce power to maintain control
2 Airspeed Increase above VMCa
3 Power Lever (Operating engine) AS REQUIRED
4 Inoperative engine : SECURE as per ENGINE SECURING Procedure
Limitations pag 2-9
Autofeather system limits
WARNING : no take off is authorized with AF inoperative
1 The AF system must be pre flight checked operational prior to take off
2 The AF system must be used for TO and Landing operations
The P180 is not allowed to TO with AF inoperative ; besides, the single-engine climb performance , and all other single-engine performances, are all based on a feathered propeller.
Different things are the cause of the high VMCa (windmilling) : among them, the fact that the tail arm is short, and this impact not only on the rudder authority, but also on the tail damping during a dynamic engine failure, where the yaw rate has been considered extremely high .
Daniel
since I am unable to upload attachments (I am waiting suggestions from the Administrator)
I copy herebelow the relevant parts of the AFM (you can anyway download it from different websites)
Rev.0 Issued 21-oct-2005
Pag.2-2
Minimum control speed
Autofeather system operative 100 KIAS
Propeller windmilling 128 KIAS
Engine failure in flight below Vmca
Pag 3-6
1 Power lever (operating engine) Reduce power to maintain control
2 Airspeed Increase above VMCa
3 Power Lever (Operating engine) AS REQUIRED
4 Inoperative engine : SECURE as per ENGINE SECURING Procedure
Limitations pag 2-9
Autofeather system limits
WARNING : no take off is authorized with AF inoperative
1 The AF system must be pre flight checked operational prior to take off
2 The AF system must be used for TO and Landing operations
The P180 is not allowed to TO with AF inoperative ; besides, the single-engine climb performance , and all other single-engine performances, are all based on a feathered propeller.
Different things are the cause of the high VMCa (windmilling) : among them, the fact that the tail arm is short, and this impact not only on the rudder authority, but also on the tail damping during a dynamic engine failure, where the yaw rate has been considered extremely high .
Daniel
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Daniel - Thanks. Looks like I was right, even on the Piaggio.
So I guess it's on the King Air guys now to post up something that says the AF on their birds is optional.
So I guess it's on the King Air guys now to post up something that says the AF on their birds is optional.
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It's model dependant. The old 200 model King Airs with the three blade propellers came from the factory with auto feather as an option. From what I was told. It wasn't "cool " or "real men feather there own props". So initially the system was slow to be accepted to the flying population. Still today many older 200's are flying around with no autofeather fitted.
When Beechcraft built the B200 fitted with the new 4 blade Raisbeck props during the certification they discovered that the Vmca increased from 91KIAS to 108KIAS with a windmilling propellor. So a failed autofeather system on the 4 blade versions is a "no go" item and no provision is made in the MEL for you to dispatch with out auto feather.
From a Raisbeck King Air manual
AUTO FEATHERING SYSTEMS:
The Beech Propeller Autofeathering System must be installed, operational, and armed for takeoff, climb and approach.
CAUTION
With one-engine either at idle or inoperative, flaps up and propeller windmilling, VMCA may be as high as 108 KIAS.
When Beechcraft built the B200 fitted with the new 4 blade Raisbeck props during the certification they discovered that the Vmca increased from 91KIAS to 108KIAS with a windmilling propellor. So a failed autofeather system on the 4 blade versions is a "no go" item and no provision is made in the MEL for you to dispatch with out auto feather.
From a Raisbeck King Air manual
AUTO FEATHERING SYSTEMS:
The Beech Propeller Autofeathering System must be installed, operational, and armed for takeoff, climb and approach.
CAUTION
With one-engine either at idle or inoperative, flaps up and propeller windmilling, VMCA may be as high as 108 KIAS.
Last edited by Brian Abraham; 30th May 2013 at 07:14.
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Way before you could have Raisbeck installed by the factory, Beech sold the B200 with four bladed props (McCauleys and not Hartzells like the Raisbeck props) and AF installed/required.
I think thats bollocks. Equipping an airplane often is a balance between budget and requirements. Most KingAirs donīt have the fire extingiushers installed, they were at least optional. Why? Cost. I canīt believe anyone would think of fexs as "uncool".
Certainly nobody who had the "fun" of spurios fire warnings that the old system created fairly often. (I had my fair share of them)
I have flown 3 bladed 200s/B200 and 4 bladed ones. The difference of behaviour when OEI is dramatic.
And the cost of re-equipping with AF is high, I remember a case were the B200 was bought in from the US with 3 blade props and couldn`t get certified in Germany and had to be re-equipped with AF and the Raisbeck props.
I canīt remember the exact numbers, but it was quite some bucks on top of the Raisbecks...
it wasn't "cool " or "real men feather there own props". So initially the system was slow to be accepted to the flying population.
Certainly nobody who had the "fun" of spurios fire warnings that the old system created fairly often. (I had my fair share of them)
I have flown 3 bladed 200s/B200 and 4 bladed ones. The difference of behaviour when OEI is dramatic.
And the cost of re-equipping with AF is high, I remember a case were the B200 was bought in from the US with 3 blade props and couldn`t get certified in Germany and had to be re-equipped with AF and the Raisbeck props.
I canīt remember the exact numbers, but it was quite some bucks on top of the Raisbecks...
Last edited by His dudeness; 22nd Jul 2013 at 07:32.
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It's model dependant. The old 200 model King Airs with the three blade propellers came from the factory with auto feather as an option. From what I was told. It wasn't "cool " or "real men feather there own props". So initially the system was slow to be accepted to the flying population. Still today many older 200's are flying around with no autofeather fitted.
When Beechcraft built the B200 fitted with the new 4 blade Raisbeck props during the certification they discovered that the Vmca increased from 91KIAS to 108KIAS with a windmilling propellor. So a failed autofeather system on the 4 blade versions is a "no go" item and no provision is made in the MEL for you to dispatch with out auto feather.
From a Raisbeck King Air manual
AUTO FEATHERING SYSTEMS:
The Beech Propeller Autofeathering System must be installed, operational, and armed for takeoff, climb and approach.
CAUTION
With one-engine either at idle or inoperative, flaps up and propeller windmilling, VMCA may be as high as 108 KIAS.
When Beechcraft built the B200 fitted with the new 4 blade Raisbeck props during the certification they discovered that the Vmca increased from 91KIAS to 108KIAS with a windmilling propellor. So a failed autofeather system on the 4 blade versions is a "no go" item and no provision is made in the MEL for you to dispatch with out auto feather.
From a Raisbeck King Air manual
AUTO FEATHERING SYSTEMS:
The Beech Propeller Autofeathering System must be installed, operational, and armed for takeoff, climb and approach.
CAUTION
With one-engine either at idle or inoperative, flaps up and propeller windmilling, VMCA may be as high as 108 KIAS.
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I know my reply is a little late but I haven't been on for a while.
Our company operates 2 King Airs. We do full run ups for first flight of the day and abbreviated for subsequent flights. As far as one poster put it about economy, in our company if it doesn't work and isn't an MEL item we don't go.
I was doing an interview ride with a potential new hire a while ago. He was typed in the aircraft and currently flying the type. It was obvious that he wasn't practiced with the run up procedures. He told us that the company he was with didn't want to slow the passengers down by doing them.
When asked if he did it on reposition flights he said no. This was even though he did reposition flights quite often.
The excuse of being pressed for time is pretty lame. I've always been told, if you're in a hurry you're dangerous. I would say that if you do it every day it only takes an extra 3 minutes at most. You just need to develop a flow that works for you then use the checklist as review.
While I can't say what stopped him from getting the job, I will say that it didn't help that he took the need to practice proper procedures so lightly.
I believe that it can be a slippery slope. Today you don't do the overspeed governor and rudder boost, primary governor and prop solenoid or autofeather tests. Then what's next? EFIS, Autopilot, deice anti-ice, ADC, TAWS, TCAS? Heck, why don't we just skip the pre-flight?
Our company operates 2 King Airs. We do full run ups for first flight of the day and abbreviated for subsequent flights. As far as one poster put it about economy, in our company if it doesn't work and isn't an MEL item we don't go.
I was doing an interview ride with a potential new hire a while ago. He was typed in the aircraft and currently flying the type. It was obvious that he wasn't practiced with the run up procedures. He told us that the company he was with didn't want to slow the passengers down by doing them.
When asked if he did it on reposition flights he said no. This was even though he did reposition flights quite often.
The excuse of being pressed for time is pretty lame. I've always been told, if you're in a hurry you're dangerous. I would say that if you do it every day it only takes an extra 3 minutes at most. You just need to develop a flow that works for you then use the checklist as review.
While I can't say what stopped him from getting the job, I will say that it didn't help that he took the need to practice proper procedures so lightly.
I believe that it can be a slippery slope. Today you don't do the overspeed governor and rudder boost, primary governor and prop solenoid or autofeather tests. Then what's next? EFIS, Autopilot, deice anti-ice, ADC, TAWS, TCAS? Heck, why don't we just skip the pre-flight?
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Teldorserious I looked at the current IML discs for the 90 and 200 series King Airs.
There is no listing for autofeather on 90's before LJ-362. The F-90 show it as optional equipment on all S/N's, and they all had 4 bladed props.
The 200/ B200 disc show autofeather as optional equipment all the way to the ProLine 21 equipped aircraft BB-1834 and up with a few holes in the coverage.
It may have been a mandatory option with certain props...but it was an option.
His dudeness: My boss had to add autofeather to more than a few new aircraft, the salesmen would order the aircraft without a/f and the buyer would want it. His best recollection was that it cost $30,000 USD to add it...in 1978
There is no listing for autofeather on 90's before LJ-362. The F-90 show it as optional equipment on all S/N's, and they all had 4 bladed props.
The 200/ B200 disc show autofeather as optional equipment all the way to the ProLine 21 equipped aircraft BB-1834 and up with a few holes in the coverage.
It may have been a mandatory option with certain props...but it was an option.
His dudeness: My boss had to add autofeather to more than a few new aircraft, the salesmen would order the aircraft without a/f and the buyer would want it. His best recollection was that it cost $30,000 USD to add it...in 1978
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His dudeness: My boss had to add autofeather to more than a few new aircraft, the salesmen would order the aircraft without a/f and the buyer would want it. His best recollection was that it cost $30,000 USD to add it...in 1978
