Take-Off Power - How often?
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TO power per hour?
Taking up the number of take-offs per hour, there's a limitation on certain components of some Bells (205/212+others?) based upon RIN. You'll find it mentioned in small type in Bell publications.
I'm not familiar enough with these types to know exactly what a RIN is or how it's calculated, but I always had the impression it was related to the number of 'high power events' the rotor system was subjected to per hour (average). Presumably these 'high power events' were within regular limits, and yet somehow impacted upon the life of some components.
Anybody got more detail?
I'm not familiar enough with these types to know exactly what a RIN is or how it's calculated, but I always had the impression it was related to the number of 'high power events' the rotor system was subjected to per hour (average). Presumably these 'high power events' were within regular limits, and yet somehow impacted upon the life of some components.
Anybody got more detail?
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Why should it be called Take Off Power?
I can use it for upto 5 Mins on Take Off without exceeding any limitation, however use it momentarily on a landing when encountering a strong downdraught in the mountains and I'm outside limits?
Exactly what difference is it to the engine? High TOT is high TOT.
I can use it for upto 5 Mins on Take Off without exceeding any limitation, however use it momentarily on a landing when encountering a strong downdraught in the mountains and I'm outside limits?
Exactly what difference is it to the engine? High TOT is high TOT.
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Thanks Gents some very interesting feedback. Most of it I have heard before…the beans explanation is a new one to me and a nice way to describe it … reminds me of life at Club-Med… and I appreciate the ‘Sunday drivers’ perspective as much as the guy who flies in the part of Mexico that is as hot as the Jalapenos.
I also understand the argument that a machine that is worked very hard will not get to TBO, and I like to think that in those cases the power assurance checks, SOAP programmes, chip lights and similar safety features and techniques will assist operators to arrange for timely premature removal of the components that have taken a hammering before the safety margin has been significantly eroded. After all we don’t tell the guy with the mallet not to hit so hard because he might have to buy a new one during his lifetime. Nor do we let Hertz tell us that we can’t drive faster than 45 mph. To many of us a helicopter is a tool to be used in business, to make money, as is deemed appropriate by the owner, not something to be taken out for a ride around the block on a Sunday morning and the view that retaining its resale value is paramount. But we do insist that the machine be operated and maintained in accordance with the manufacturer’s limits and recommendations.
I am looking at the legal considerations of pilots, that for operational and contractual reasons, are having to use power in the takeoff range for periods in any one flight that are longer than the ‘5 minute limit’ stipulated in the Flight Manual.
I am sure that there are a number of pilots who have flown military or law enforcement missions, and probably ENG missions too, where they have been required to remain in an OGE hover for extended periods of time. If these pilots use ‘take-off’ rated power in excess of the 5 minutes for a continuous period then it would seem that they are operating outside flight manual limits. If they move into forward flight and do a large orbit allowing air flow through the coolers etc. before they return to the OGE hover are they now back to operating within the flight manual limits?
If takeoff power is for takeoff purposes only why do the ‘hover ceiling’ graphs specifically state ‘takeoff power’? Why do we not have hover performance graphs to use for the maximum continuous power rating?
Does the takeoff range on the Bell 206 torque gauge, which we are told is connected with a KIAS limitation and mast moment, have any real implication with regard to hovering flight?
Why is it that if the same old questions get asked every year, come summer time, the manufacturer doesn’t do something to clarify the situation once and for all. If a flight manual amendment isn’t commercially viable there must be other ways that they could get the message across; Ski’s ‘HeliProps’ is one example that comes to mind.
Bell’s representatives, in face to face meetings, are unable / unwilling to provide the ‘party line’ answer, probably because of legal and liability issues. Is it possible that someone from Bell could use the medium of an anonymous forum such as this to clarify the issue?
I also understand the argument that a machine that is worked very hard will not get to TBO, and I like to think that in those cases the power assurance checks, SOAP programmes, chip lights and similar safety features and techniques will assist operators to arrange for timely premature removal of the components that have taken a hammering before the safety margin has been significantly eroded. After all we don’t tell the guy with the mallet not to hit so hard because he might have to buy a new one during his lifetime. Nor do we let Hertz tell us that we can’t drive faster than 45 mph. To many of us a helicopter is a tool to be used in business, to make money, as is deemed appropriate by the owner, not something to be taken out for a ride around the block on a Sunday morning and the view that retaining its resale value is paramount. But we do insist that the machine be operated and maintained in accordance with the manufacturer’s limits and recommendations.
I am looking at the legal considerations of pilots, that for operational and contractual reasons, are having to use power in the takeoff range for periods in any one flight that are longer than the ‘5 minute limit’ stipulated in the Flight Manual.
I am sure that there are a number of pilots who have flown military or law enforcement missions, and probably ENG missions too, where they have been required to remain in an OGE hover for extended periods of time. If these pilots use ‘take-off’ rated power in excess of the 5 minutes for a continuous period then it would seem that they are operating outside flight manual limits. If they move into forward flight and do a large orbit allowing air flow through the coolers etc. before they return to the OGE hover are they now back to operating within the flight manual limits?
If takeoff power is for takeoff purposes only why do the ‘hover ceiling’ graphs specifically state ‘takeoff power’? Why do we not have hover performance graphs to use for the maximum continuous power rating?
Does the takeoff range on the Bell 206 torque gauge, which we are told is connected with a KIAS limitation and mast moment, have any real implication with regard to hovering flight?
Why is it that if the same old questions get asked every year, come summer time, the manufacturer doesn’t do something to clarify the situation once and for all. If a flight manual amendment isn’t commercially viable there must be other ways that they could get the message across; Ski’s ‘HeliProps’ is one example that comes to mind.
Bell’s representatives, in face to face meetings, are unable / unwilling to provide the ‘party line’ answer, probably because of legal and liability issues. Is it possible that someone from Bell could use the medium of an anonymous forum such as this to clarify the issue?
Thanks Nick; at least that gives an idea of about how many times is considered to be OK to use up to 5 min of 'Takeoff' power before starting to cut into engine life more than is ideal .
I guess the sad fact is that unless a limit is written specifically, rather than as something that can be argued about, it will be pushed to the letter rather than the spirit of it by those who choose to do so.
Given that use of the 5 minute limit more than about 2.5 times per hour will cause the engine to deteriorate more rapidly than is expected in TBO planning, I guess it follows that a machine that's been subjected to much more than about 12 - 15 minutes per hour in the T/O range for numerous hours is looking statistically worse for likelihood of an engine failure than one that's been 'babied', as some have been terming it; looking for power trends etc to catch it before it fails in that case seems a bit hopeful, to say the least.
Blender mentioned the experienced hands who advised against 'babying' aircraft; experience counts for a lot, certainly, but urban myths and dubious practices can also become accepted truth sometimes, until someone says 'hang on, is what we're doing really a good idea?'
I'm all for working to the limits, but it seems to me to go against logic to pretend that lowering the lever momentarily into the green range and going for it again somehow complies with the manufacturer's intent.
I guess the sad fact is that unless a limit is written specifically, rather than as something that can be argued about, it will be pushed to the letter rather than the spirit of it by those who choose to do so.
Given that use of the 5 minute limit more than about 2.5 times per hour will cause the engine to deteriorate more rapidly than is expected in TBO planning, I guess it follows that a machine that's been subjected to much more than about 12 - 15 minutes per hour in the T/O range for numerous hours is looking statistically worse for likelihood of an engine failure than one that's been 'babied', as some have been terming it; looking for power trends etc to catch it before it fails in that case seems a bit hopeful, to say the least.
Blender mentioned the experienced hands who advised against 'babying' aircraft; experience counts for a lot, certainly, but urban myths and dubious practices can also become accepted truth sometimes, until someone says 'hang on, is what we're doing really a good idea?'
I'm all for working to the limits, but it seems to me to go against logic to pretend that lowering the lever momentarily into the green range and going for it again somehow complies with the manufacturer's intent.
Last edited by Arm out the window; 17th Jun 2005 at 06:12.
'If takeoff power is for takeoff purposes only why do the ‘hover ceiling’ graphs specifically state ‘takeoff power’?'
The manufacturers rightly consider you will have to put the aircraft in hover before taking off.
'Why do we not have hover performance graphs to use for the maximum continuous power rating?'
Some aircraft have different graphs for hover at TO power and at MCP. For the 365 N2 the difference in MTOW is 720 kgs at 40 C.
ATN
The manufacturers rightly consider you will have to put the aircraft in hover before taking off.
'Why do we not have hover performance graphs to use for the maximum continuous power rating?'
Some aircraft have different graphs for hover at TO power and at MCP. For the 365 N2 the difference in MTOW is 720 kgs at 40 C.
ATN
ATN, I'd say it's more likely that the manufacturers understandably want to make their machine look as good as possible in the specs, and there would also be defined standards that apply to the certification of aircraft and relate to the types of proving flights and documentation you must produce.
So the hover ceiling would use maximum power, because the helicopter can actually hover under the specified conditions.
You don't necessarily have to be able to hover to take off, just get light enough on the skids or wheels and you can do the old 'cushion creep' - not all that pretty but it works.
So the hover ceiling would use maximum power, because the helicopter can actually hover under the specified conditions.
You don't necessarily have to be able to hover to take off, just get light enough on the skids or wheels and you can do the old 'cushion creep' - not all that pretty but it works.
AOTW,
I used this trick on some occasions when there was no other options, but
I have never seen this procedure approved/certified in any RFM. So manufacturers do have to produce data and graphs for hover IGE and OGE and specify at which power settings the perfs have been obtained. IMO it does make sense to associate HOGE and T/O PWR limitations since longer periods of time are spent HOGE than HIGE. More data are available for recent and sophisticated aircraft than for their old and basic predecessors.
ATN
I used this trick on some occasions when there was no other options, but
I have never seen this procedure approved/certified in any RFM. So manufacturers do have to produce data and graphs for hover IGE and OGE and specify at which power settings the perfs have been obtained. IMO it does make sense to associate HOGE and T/O PWR limitations since longer periods of time are spent HOGE than HIGE. More data are available for recent and sophisticated aircraft than for their old and basic predecessors.
ATN
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Interesting thread...
Are there any turbine helis with "powertrain life" or "rate of powertrain damage" indicators? Reading Nick's account of the blade creep bean (and G/box tooth/bearing life), makes me wonder whether such an instrument would tell a clearer picture about heli duty usage. It would need to be part of the powertrain ECU (or is it FADEC?).
Mart
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John Eacott had the right observation, and Graviman hit it,too.
There are now tools at hand to count the beans coming out, and to take good test data from the qualification tests to determine how many beans there are to start with.
I believe we are at the threshold of a new way to certify the aircraft system as a whole, instead of a collection of disconnected parts.
Turbine engines have time-temperature recorders that estimate creep life (the true limiter for turbines.) Time to extend that to allow "variable limits" within the bounds of safety, but tied to digital systems that make a red flag pop up on the displays and say "Out of Beans".
BTW, TO power is OK for landing, and a terminal hover to pick someone up is allowable at TO power. Besides, if I am down there, do NOT leave me there because the flight manual says so!!
There are now tools at hand to count the beans coming out, and to take good test data from the qualification tests to determine how many beans there are to start with.
I believe we are at the threshold of a new way to certify the aircraft system as a whole, instead of a collection of disconnected parts.
Turbine engines have time-temperature recorders that estimate creep life (the true limiter for turbines.) Time to extend that to allow "variable limits" within the bounds of safety, but tied to digital systems that make a red flag pop up on the displays and say "Out of Beans".
BTW, TO power is OK for landing, and a terminal hover to pick someone up is allowable at TO power. Besides, if I am down there, do NOT leave me there because the flight manual says so!!
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The Bell Retirement Index Number (RIN) is related to takeoffs. For most models, it's 1:1, meaning one takeoff increments one RIN. On the 212, it's different, but I haven't flown a 212 in so long I'm afraid to say exactly what the formula is, other than that it's not 1:1. Turbomeca has the same thing, but they call it cycles, and have an incredibly complicated formula that requires counting every time the N1 goes above or below 85%, and by how much. Nobody I know uses it, instead using the 'lump' calculation, basically counting one cycle per takeoff which had a start preceding it, and .15 if there was no start. It uses cycles more quickly, but better engine cycles than brain neurons. This may be different for other engines.
Personally, for takeoff and landing, all I care is that nothing goes above the redline. That's why they put red lines on the gages. Max continuous is something different, and seems to often be limited by operators to something less than what the manufacturer specifies, just to try to keep all the beans in one pile as long as possible.
Personally, for takeoff and landing, all I care is that nothing goes above the redline. That's why they put red lines on the gages. Max continuous is something different, and seems to often be limited by operators to something less than what the manufacturer specifies, just to try to keep all the beans in one pile as long as possible.
Lycoming/Honeywell have a similar count for the LTS101, requiring logging of max N1 when flown, and then a fun set of calculations to derive Ng and Np cycles. Something like total number of Ng excursions (>90% to <78% to > 90%), or Np excursions (>85% - <85% - >85%). Having taken the "lump" calculation in earlier years, it's proved to be worth recording Ng and spending a bit of time calculating Ng and Np cycles, for the better life of the engine.
Tedious, though........and hard to really keep an eye on the N1 gauge when sling loading/fire fighting
And don't bother to tell me that I could spend c$50k on an automatic bit of kit that will do it all for me, thanks 
Tedious, though........and hard to really keep an eye on the N1 gauge when sling loading/fire fighting
And don't bother to tell me that I could spend c$50k on an automatic bit of kit that will do it all for me, thanks
Maybe the manufcaturers should stop calling it take-off power and call it contingency or some similar term. I know it will still mean the same thing but it will stop pilots arguing whether it can be used for landing or hovering.
It is very unhelpful to say it is a five minute rating and then not specify the frequency it may be used or more importantly the frequency of use the manufacturer has assumed.
It certainly gives the manufacturer a legal get out when the engine fails and the investigation shows that the 5 minute power was being used almost continuously - they then say 'we only expected it to be used 2 1/2 times an hour - we just didn't tell anyone that"
I like Nicks bean analogy but if the number of beans is known at the start and the rate of bean usage the manufacturers have calculated to make the zero bean count happen at the expected engine change hours - then operators can at least give guidance to their pilots and you won't have one guy using 50 beans and the next 500 beans to do the same job.
It is very unhelpful to say it is a five minute rating and then not specify the frequency it may be used or more importantly the frequency of use the manufacturer has assumed.
It certainly gives the manufacturer a legal get out when the engine fails and the investigation shows that the 5 minute power was being used almost continuously - they then say 'we only expected it to be used 2 1/2 times an hour - we just didn't tell anyone that"
I like Nicks bean analogy but if the number of beans is known at the start and the rate of bean usage the manufacturers have calculated to make the zero bean count happen at the expected engine change hours - then operators can at least give guidance to their pilots and you won't have one guy using 50 beans and the next 500 beans to do the same job.
I think crab@SAAvn got it right there : )
The manuals are more or less written by lawyer´s and it´s easiest for the manufacturer to use the "Take off power" reference in the manual so that when you come in for landing and run out of power, altitude and ideas all at once then they can say that you were only supposed to calculate on maximum continious power for the landing!
At least it´s a good argument in court and they need to protect themselves in overly litigious US of A..
But in real life of course the engine really doesn´t care if it´s taking off or landing when you use the 5 min rating.
And somebody mentioned that the manual includes hover tables calculated on "Take-off power" and he´s right, not likely that you are really just using that power for take off when hovering out of ground effect at 6.000' !
Nick´s bean counting system is pretty good, but for those asking about how many beans are there in the jar in the first place, then it´s not that simple really, because it´s a variable depending on the conditions the engine is operated in.
An engine operated in cold climate free of dust and salt & always started with GPU and always treated right are going to have more beans in the jar than an engine that started out life in the Sahara desert! Even if both were always operated well within any limits!
And those with ideas about some kind of health monitoring system for engine and/or gearbox.. please spare me.. the costs would be prohibitive for small helicopters and I´m in bad enough mood as it is after reading the latest AD issued on my engine
In regard to the discussion about RIN. On the 206 you have to figure one RIN for take-off, another for landing when throttling down to idle. So one trip with takeoff and landing is 2 RIN´s. Also one sling cycle is one RIN.
John Eacott..
Gotta love that cycle system for the LTS 101 add to it sling work and then it gets really complicated
edited to add RIN talk!
The manuals are more or less written by lawyer´s and it´s easiest for the manufacturer to use the "Take off power" reference in the manual so that when you come in for landing and run out of power, altitude and ideas all at once then they can say that you were only supposed to calculate on maximum continious power for the landing!
At least it´s a good argument in court and they need to protect themselves in overly litigious US of A..
But in real life of course the engine really doesn´t care if it´s taking off or landing when you use the 5 min rating.
And somebody mentioned that the manual includes hover tables calculated on "Take-off power" and he´s right, not likely that you are really just using that power for take off when hovering out of ground effect at 6.000' !
Nick´s bean counting system is pretty good, but for those asking about how many beans are there in the jar in the first place, then it´s not that simple really, because it´s a variable depending on the conditions the engine is operated in.
An engine operated in cold climate free of dust and salt & always started with GPU and always treated right are going to have more beans in the jar than an engine that started out life in the Sahara desert! Even if both were always operated well within any limits!
And those with ideas about some kind of health monitoring system for engine and/or gearbox.. please spare me.. the costs would be prohibitive for small helicopters and I´m in bad enough mood as it is after reading the latest AD issued on my engine
In regard to the discussion about RIN. On the 206 you have to figure one RIN for take-off, another for landing when throttling down to idle. So one trip with takeoff and landing is 2 RIN´s. Also one sling cycle is one RIN.
John Eacott..
Gotta love that cycle system for the LTS 101 add to it sling work and then it gets really complicated
edited to add RIN talk!
Last edited by Aesir; 18th Jun 2005 at 08:24.
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Maybe some of these helicopters ought to have the same system as the Dauphin N3. With that, the cycle count is done for you by the FADEC. It's just a matter of having a look on the overhead panel after flight and logging the N1 and N2 cycles from the computer for entry into the tech log.
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Aesir,
"And those with ideas about some kind of health monitoring system for engine and/or gearbox.. please spare me.. the costs would be prohibitive for small helicopters..."
The main time limited component in a turbine powered heli is the turbine blade. The hot temperature and centrifugal force slowly but inevitably cause the blades to stretch, or "creep". At some critical value of stretch the creep becomes exponentially worse with usage, at which point the engine is destined for a rebuild (or used as an aero engineering college demo ). Turbine monitoring system would indicate when blades were about to wear out the shroud, or suffer catastrophic failure. Engine life could then be pushed (safely) to the limit of the design - even better if a proximity sensor actually detected the blade creep. Naturally this system is best supplied as part of the powertrain.
Piston powertrains have time limited components, generally limited by mechanical wear since the steel components will be designed to stay below fatigue limits (non ferrous components do have a fatigue life, but it is not generally severe). Bearings and gear teeth will eventually "spall" (basically spit out little bits of the hardened surface) when the wear causes localised stresses. Good oils will go a long way to protecting a piston engine powertrain, especially the crankshaft & camshaft bearing shells. Temperature management is required only to avoid thermal stess fatigue on the block, but if done sensibly prolongs life indefinately. Again, an OEM time-life monitor would allow the engine (with specified oils and componentry) to reach the maximum time between overhauls.
I'm frankly amazed that Continental or Lycombing don't consider developing a 500SHP turbo piston plant for (say) 206 and similar installation, for precisely these reasons. Improved fuel usage would counter inevitable weight increase. Maybe the next gen of Av-Jet piston engines will change all this...
Mart
[Edit: To correct for understanding that Nick's "beans" actually refer to all time limited components, and not just turbine blades.]
"And those with ideas about some kind of health monitoring system for engine and/or gearbox.. please spare me.. the costs would be prohibitive for small helicopters..."
The main time limited component in a turbine powered heli is the turbine blade. The hot temperature and centrifugal force slowly but inevitably cause the blades to stretch, or "creep". At some critical value of stretch the creep becomes exponentially worse with usage, at which point the engine is destined for a rebuild (or used as an aero engineering college demo
). Turbine monitoring system would indicate when blades were about to wear out the shroud, or suffer catastrophic failure. Engine life could then be pushed (safely) to the limit of the design - even better if a proximity sensor actually detected the blade creep. Naturally this system is best supplied as part of the powertrain.Piston powertrains have time limited components, generally limited by mechanical wear since the steel components will be designed to stay below fatigue limits (non ferrous components do have a fatigue life, but it is not generally severe). Bearings and gear teeth will eventually "spall" (basically spit out little bits of the hardened surface) when the wear causes localised stresses. Good oils will go a long way to protecting a piston engine powertrain, especially the crankshaft & camshaft bearing shells. Temperature management is required only to avoid thermal stess fatigue on the block, but if done sensibly prolongs life indefinately. Again, an OEM time-life monitor would allow the engine (with specified oils and componentry) to reach the maximum time between overhauls.
I'm frankly amazed that Continental or Lycombing don't consider developing a 500SHP turbo piston plant for (say) 206 and similar installation, for precisely these reasons. Improved fuel usage would counter inevitable weight increase. Maybe the next gen of Av-Jet piston engines will change all this...
Mart
[Edit: To correct for understanding that Nick's "beans" actually refer to all time limited components, and not just turbine blades.]
Last edited by Graviman; 18th Jun 2005 at 23:51.
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No Mart, the beans refer especially to all time-limited components.
Regarding the cost, I would bet dollars to donuts that the electronics and computation in the cell phone that all ppruners carry are more complex and expensive than those needed to count beans. The difference is tyhe number of units sold to cover the development. I do promise you that the list of R22 costs for components would demonstrate to normal people how economically imperitive it is (let alone safety concerns) that we move toward accounting directly the remaining life.
Gomer Pylot, your wish to have simple red lines is like my wish as a boy to have all the cream chees and jelly sandwiches in the world available, it is a dream. Do yoy actually think we put the lines where things break? Do you actually think there is such a relationship, where a red line marks the danger point, and all things less are wonderful, and .001% beyond that red line is death and destruction?
I give a class on where the red lines come from (having painted more than my fair share of them on gages) and I can assure you, almost none of the red lines you see are due to an actual "it will break right now if you exceed this" limit. Alomost all red lines carry with them an assumed life, an assumed operating philosophy, and an assumed degree of inspection.
The science of determining safe limits and life is the essence of engineering, and is fraught with ethical decisions like "safer" and "enough" and "practical".
Let me ask you, in driving your family, does a traffic light signal safety? If you travel the speed limit, are you truly assured that nothing unsafe can happen to you? If you inflate your tires to 33 psi, will they never blow out?
Gomer Pylot, wish for Mother Helicopter God to paint lines in places so you are always covered, but if we painted them to assure you Nothing Ever would Happen, your payload would be 10% of what it is now, your cost to operate 10 times higher, and your actual safety would be hardly different, since odds are you would take that assuredly safe machine, and CFIT yourself with it just as easily, or misjudge that distance, or overload it unintentionally. When we fix the real cause of helicopter accidents, we can spread our knowledge to the rest of human endevors. The enemy is usually us, not our machines.
Regarding the cost, I would bet dollars to donuts that the electronics and computation in the cell phone that all ppruners carry are more complex and expensive than those needed to count beans. The difference is tyhe number of units sold to cover the development. I do promise you that the list of R22 costs for components would demonstrate to normal people how economically imperitive it is (let alone safety concerns) that we move toward accounting directly the remaining life.
Gomer Pylot, your wish to have simple red lines is like my wish as a boy to have all the cream chees and jelly sandwiches in the world available, it is a dream. Do yoy actually think we put the lines where things break? Do you actually think there is such a relationship, where a red line marks the danger point, and all things less are wonderful, and .001% beyond that red line is death and destruction?
I give a class on where the red lines come from (having painted more than my fair share of them on gages) and I can assure you, almost none of the red lines you see are due to an actual "it will break right now if you exceed this" limit. Alomost all red lines carry with them an assumed life, an assumed operating philosophy, and an assumed degree of inspection.
The science of determining safe limits and life is the essence of engineering, and is fraught with ethical decisions like "safer" and "enough" and "practical".
Let me ask you, in driving your family, does a traffic light signal safety? If you travel the speed limit, are you truly assured that nothing unsafe can happen to you? If you inflate your tires to 33 psi, will they never blow out?
Gomer Pylot, wish for Mother Helicopter God to paint lines in places so you are always covered, but if we painted them to assure you Nothing Ever would Happen, your payload would be 10% of what it is now, your cost to operate 10 times higher, and your actual safety would be hardly different, since odds are you would take that assuredly safe machine, and CFIT yourself with it just as easily, or misjudge that distance, or overload it unintentionally. When we fix the real cause of helicopter accidents, we can spread our knowledge to the rest of human endevors. The enemy is usually us, not our machines.
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Nick, I know very well that redlines don't represent an "It will break above here" point, nor that nothing will ever break below them. Engines can fail while at idle - anything mechanical can break any time. My comment simply meant that as long as I stay below the redlines I'm legal, I don't have to shut down and write up an exceedance, and probably nothing bad will happen. I just don't want to have to read charts while flying with something close to the redline, and the N1 bias system on the S76A++ represents what I'm talking about. Just keep the N1 below the painted red line, and you're below the limits, regardless of the temperature and altitude.
As long as no red lines are exceeded, I don't have to make an entry in the logbook, and that's my main concern. I'm always prepared for something to fail, but so far, after 37 years, nothing has, and a large percentage of the 20,000+ takeoffs I've done have been at one redline or another, or at least very close to one. I keep my fingers crossed while knocking on my head, and stay ready for something to surprise me.
As long as no red lines are exceeded, I don't have to make an entry in the logbook, and that's my main concern. I'm always prepared for something to fail, but so far, after 37 years, nothing has, and a large percentage of the 20,000+ takeoffs I've done have been at one redline or another, or at least very close to one. I keep my fingers crossed while knocking on my head, and stay ready for something to surprise me.
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Gomer Pilot,
Let me extrapolate your comment (a very apt one, IMHO) to say:
All limits and procedures must be realized in the hands of the pilot and crew. They are not engineering abstracts nor are they legalisms, they are the best guidance we have to aid the crew.
Let me extrapolate your comment (a very apt one, IMHO) to say:
All limits and procedures must be realized in the hands of the pilot and crew. They are not engineering abstracts nor are they legalisms, they are the best guidance we have to aid the crew.
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Yes, Nick, but you're speaking as a test pilot, not as a chief pilot nor as an FAA inspector. I appreciate what you do as a test pilot, but once the aircraft gets a type certificate and is in my hands, your contribution wanes, and the contributions of the others becomes paramount. Logic and common sense have little to do with enforcement actions. As a pilot, I have no idea what you've done during testing. All I have to work with are the flight manual and the limitations. You supposedly guarantee that staying below the redlines won't cause any immediate catastrophes, and that implies that going above them slightly won't either. There is no way that an increase of 1% torque, or one knot, or whatever, will result in immediate destruction, but it can result in immediate certificate or employment action. That's the distinction we have to make. Thus, I try to always stay within limits, not just for my own physical safety, but for the safety of my job and certificate.