2.4% regulatory climb gradient for single engine
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far 25.121 b) Takeoff; landing gear retracted. In the takeoff configuration existing at the point of the flight path at which the landing gear is fully retracted, and in the configuration used in §25.111 but without ground effect, the steady gradient of climb may not be less than 2.4 percent for two-engine airplanes, 2.7 percent for three-engine airplanes, and 3.0 percent for four-engine airplanes, at V2 and with --
you might want to read john's reply explaining why the 2,4% can vary. This is definitely not the correct answer.
The point at which the performance must be demonstrated is emphasised
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OK... Ill toss a grenade into this campfire...
FAR 23 and 25 are CERTIFICATION standards... The manufacturer (not the pilot) is responsible for certifying the aircraft therefor these regulations are applicable to someone wanting to obtain or change the type design of the aircraft.
Sec. 25.1
Applicability.
(a) This part prescribes airworthiness standards for the issue of type certificates, and changes to those certificates, for transport category airplanes.
(b) Each person who applies under Part 21 [New] for such a certificate or change must show compliance with the applicable requirements in this part.
Part 25 aircraft are not allowed the use of TR's, must have brakes worn to limits, and have an Engine Failure Recognition time built into performance calculations. Does this mean pilots are not allowed to use TRs, should always have worn brakes, and wait 2 seconds after Vef to initiate an abort? Of course not...
Remember that when the FAA determines a new aircraft complies with ALL of Part 25, it is issued a Type Certificate. As long as the aircraft continues to meet requirements of the TC, it complies with Part 25 (among others) and the Airworthiness Certificate is valid. It is not up to the pilots to ensure compliance with 25.903, 33.76 or 25.1455 any more than it is their responsibility to ensure compliance with 25.121. The aircraft met the requirements when it was certified and WAT conditions will not invalidate an Airworthiness Certificate.
Aircraft Certification and Climb requirements
During certification, Part 25 only requires that manufacturers establish weights, altitudes and temperatures (WAT) that produce particular climb gradients (see Part 25.111, 25.115, and 25.121) and publish that data in the AFM (it would require about 5 pages). However, I have hundreds of pages of WAT data for climb gradients ranging from 0.0% 2nd segment OEI to as high as 14% using weights lighter that my BEW (9% is about the most realistic number I can achieve OEI). Why are they publishing such wide ranging data? Because there is no regulatory requirement that an aircraft actually have a 2.4% climb gradient (or any other gradient) under every possible WAT combination when it comes on off the production line (its physically impossible). The minimum legal climb gradients that a pilot will be required to meet will be established by a number of variables ranging from OpSpecs to country of registration.
All US registered aircraft must meet the applicable requirements of Part 91 unless they are subject more stringent regulation. Turbojet aircraft are no exception. An interesting point is that under Part 91, there are no regulations that require climb requirements above 35' be calculated by a pilot (91.605). While WAT were established during aircraft certification that produced particular gradients, the aircraft does not have to be operated at those WATs. As long as there is approved data in the AFM (again, I have data for 0.0% 2nd segment OEI operation) and you do not exceed a published limitation in the AFM, you are legal for a Part 91 flight.
Accept a departure procedure or instrument approach (MACG), operate under 121, 135, 125 or just want to physically climb over anything taller than a lake with OEI and it gets more complicated.. Legal does not mean safe.
SIDS and DPs
I think this was in some earlier posts but if you accept a departure procedure, you are expected to maintain the appropriate climb gradient – all engines operating. Does your acft manufacturer publish all engines operating climb data? Mine does not, so (if yours does, skip ahead) how does one know if they will meet the climb requirements without a AFM data. You don’t….
You will not find anything in the regulations or AFMs that allows you to use OEI data to calculate all engine operating climb gradient. Would your Check Airman let you use a flaps 12 table to calculate a flaps 20 take off?. Of course not...
As logical as the argument may be, it isn’t legal (remember, Safe does not mean Legal).
FYI - There have been some ALJ decisions and FSIM guidance that is slowly changing this but, as of now, this is what we have.
Engine Failure
Lose an engine at V1 and what are you legally required to do under Part 91? Assuming you have decided you have an emergency? Nothing.
Hopefully you have made some calculations with regards to the laws of physics but TERPS, FARs and AFMs do not trump Emergency authority. Climb at 0.0 westbound across the Pacific until you have burned off fuel – that’s legal. Legal does not mean safe.
That should be enough dynamite in the campfire for one night.. I welcome your input and the references that go with it.
FAR 23 and 25 are CERTIFICATION standards... The manufacturer (not the pilot) is responsible for certifying the aircraft therefor these regulations are applicable to someone wanting to obtain or change the type design of the aircraft.
Sec. 25.1
Applicability.
(a) This part prescribes airworthiness standards for the issue of type certificates, and changes to those certificates, for transport category airplanes.
(b) Each person who applies under Part 21 [New] for such a certificate or change must show compliance with the applicable requirements in this part.
Part 25 aircraft are not allowed the use of TR's, must have brakes worn to limits, and have an Engine Failure Recognition time built into performance calculations. Does this mean pilots are not allowed to use TRs, should always have worn brakes, and wait 2 seconds after Vef to initiate an abort? Of course not...
Remember that when the FAA determines a new aircraft complies with ALL of Part 25, it is issued a Type Certificate. As long as the aircraft continues to meet requirements of the TC, it complies with Part 25 (among others) and the Airworthiness Certificate is valid. It is not up to the pilots to ensure compliance with 25.903, 33.76 or 25.1455 any more than it is their responsibility to ensure compliance with 25.121. The aircraft met the requirements when it was certified and WAT conditions will not invalidate an Airworthiness Certificate.
Aircraft Certification and Climb requirements
During certification, Part 25 only requires that manufacturers establish weights, altitudes and temperatures (WAT) that produce particular climb gradients (see Part 25.111, 25.115, and 25.121) and publish that data in the AFM (it would require about 5 pages). However, I have hundreds of pages of WAT data for climb gradients ranging from 0.0% 2nd segment OEI to as high as 14% using weights lighter that my BEW (9% is about the most realistic number I can achieve OEI). Why are they publishing such wide ranging data? Because there is no regulatory requirement that an aircraft actually have a 2.4% climb gradient (or any other gradient) under every possible WAT combination when it comes on off the production line (its physically impossible). The minimum legal climb gradients that a pilot will be required to meet will be established by a number of variables ranging from OpSpecs to country of registration.
All US registered aircraft must meet the applicable requirements of Part 91 unless they are subject more stringent regulation. Turbojet aircraft are no exception. An interesting point is that under Part 91, there are no regulations that require climb requirements above 35' be calculated by a pilot (91.605). While WAT were established during aircraft certification that produced particular gradients, the aircraft does not have to be operated at those WATs. As long as there is approved data in the AFM (again, I have data for 0.0% 2nd segment OEI operation) and you do not exceed a published limitation in the AFM, you are legal for a Part 91 flight.
Accept a departure procedure or instrument approach (MACG), operate under 121, 135, 125 or just want to physically climb over anything taller than a lake with OEI and it gets more complicated.. Legal does not mean safe.
SIDS and DPs
I think this was in some earlier posts but if you accept a departure procedure, you are expected to maintain the appropriate climb gradient – all engines operating. Does your acft manufacturer publish all engines operating climb data? Mine does not, so (if yours does, skip ahead) how does one know if they will meet the climb requirements without a AFM data. You don’t….
You will not find anything in the regulations or AFMs that allows you to use OEI data to calculate all engine operating climb gradient. Would your Check Airman let you use a flaps 12 table to calculate a flaps 20 take off?. Of course not...
As logical as the argument may be, it isn’t legal (remember, Safe does not mean Legal).
FYI - There have been some ALJ decisions and FSIM guidance that is slowly changing this but, as of now, this is what we have.
Engine Failure
Lose an engine at V1 and what are you legally required to do under Part 91? Assuming you have decided you have an emergency? Nothing.
Hopefully you have made some calculations with regards to the laws of physics but TERPS, FARs and AFMs do not trump Emergency authority. Climb at 0.0 westbound across the Pacific until you have burned off fuel – that’s legal. Legal does not mean safe.
That should be enough dynamite in the campfire for one night.. I welcome your input and the references that go with it.
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Skky, If you believe you can legally operate at less than the certified limits simply because data outside those limits is included in your AFM I'm afraid you are mistaken.
Not so much a grenade as a big fat cream pie.
Not so much a grenade as a big fat cream pie.
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Originally Posted by skky
The aircraft met the requirements when it was certified and WAT conditions will not invalidate an Airworthiness Certificate.
Sec. 91.9 Civil aircraft flight manual, marking, and placard requirements.
(a) Except as provided in paragraph (d) of this section, no person may operate a civil aircraft without complying with the operating limitations specified in the approved Airplane or Rotorcraft Flight Manual, markings, and placards, or as otherwise prescribed by the certificating authority of the country of registry.
(a) Except as provided in paragraph (d) of this section, no person may operate a civil aircraft without complying with the operating limitations specified in the approved Airplane or Rotorcraft Flight Manual, markings, and placards, or as otherwise prescribed by the certificating authority of the country of registry.
Last edited by HazelNuts39; 21st Jul 2012 at 16:12. Reason: quotes from FAR Part 91 added
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I was told by a captain that the FMC of the aircraft (B737) calculates the performance of the aircraft on the SID for one engine out event when you enter the SID. Can someone confirm this? I was not able to find any reference to support this statement so I am not sure if this is correct.
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If I might emphasise the comments of intervening posters ..
It is not up to the pilots to ensure compliance with 25.903, 33.76 or 25.1455 any more than it is their responsibility to ensure compliance with 25.121. The aircraft met the requirements when it was certified and WAT conditions will not invalidate an Airworthiness Certificate.
Of course not .. however, it IS up to the pilot to ensure that the aeroplane is operated in a manner which is not inconsistent with the Standards embodied in the design (eg Part 25).
The minimum legal climb gradients that a pilot will be required to meet will be established by a number of variables ranging from OpSpecs to country of registration.
.. and that will be the page in the AFM which details the WAT limits.
As long as there is approved data in the AFM (again, I have data for 0.0% 2nd segment OEI operation) and you do not exceed a published limitation in the AFM, you are legal for a Part 91 flight.
That may be the case (my bolding, above) but there will be another chart which gives the WAT limits .. the how-to-use-it data will indicate that the WAT limit comes first then the other stuff ie, if the second segment charts have data apparently below the WAT limit, that will be for interpolation or similar reasons ..
Climb at 0.0 westbound across the Pacific until you have burned off fuel – that’s legal
That would be constrained by operating rules rather than design rules. However, why would one wish to do that when the aircraft should be quite capable of climbing as per the normal segmented flight path (I presume we are talking heavies) ?
I was told by a captain that the FMC ..
No reason why one couldn't set up such an animal. The sums are fine for the least capable PC .. However, the database amendment workload would escalate dramatically.
I suggest that a more reasonable expectation (unless you have documented evidence to the contrary ..) is that the box will tell you what you can expect to see OEI depending on the weight, Hp, OAT it thinks exists .. but with NIL consideration of any specific terrain .. including SIDs.
It is not up to the pilots to ensure compliance with 25.903, 33.76 or 25.1455 any more than it is their responsibility to ensure compliance with 25.121. The aircraft met the requirements when it was certified and WAT conditions will not invalidate an Airworthiness Certificate.
Of course not .. however, it IS up to the pilot to ensure that the aeroplane is operated in a manner which is not inconsistent with the Standards embodied in the design (eg Part 25).
The minimum legal climb gradients that a pilot will be required to meet will be established by a number of variables ranging from OpSpecs to country of registration.
.. and that will be the page in the AFM which details the WAT limits.
As long as there is approved data in the AFM (again, I have data for 0.0% 2nd segment OEI operation) and you do not exceed a published limitation in the AFM, you are legal for a Part 91 flight.
That may be the case (my bolding, above) but there will be another chart which gives the WAT limits .. the how-to-use-it data will indicate that the WAT limit comes first then the other stuff ie, if the second segment charts have data apparently below the WAT limit, that will be for interpolation or similar reasons ..
Climb at 0.0 westbound across the Pacific until you have burned off fuel – that’s legal
That would be constrained by operating rules rather than design rules. However, why would one wish to do that when the aircraft should be quite capable of climbing as per the normal segmented flight path (I presume we are talking heavies) ?
I was told by a captain that the FMC ..
No reason why one couldn't set up such an animal. The sums are fine for the least capable PC .. However, the database amendment workload would escalate dramatically.
I suggest that a more reasonable expectation (unless you have documented evidence to the contrary ..) is that the box will tell you what you can expect to see OEI depending on the weight, Hp, OAT it thinks exists .. but with NIL consideration of any specific terrain .. including SIDs.
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to add to JT's post..
There is nothing in the design criteria that addresses EO. It is considered an emergency op. Nothing in charts(unless you had them privately designed) will reference EO.
That is not true. There are no EO DP procedures unless you had one customed designed.
You will find that for twins, if you actually calc it out, that there is virtually no way you can meet SID requirements EO, or missed EO in gradient, unless you have a special procedure designed, or limit your weights.
if you are EO, you dont have a level off 2nd segment.
Again, nothing in procedure design criteria references EO, either in missed or departure.
There is nothing in the design criteria that addresses EO. It is considered an emergency op. Nothing in charts(unless you had them privately designed) will reference EO.
I was told by a captain that the FMC of the aircraft (B737) calculates the performance of the aircraft on the SID for one engine out event when you enter the SID. Can someone confirm this?
You will find that for twins, if you actually calc it out, that there is virtually no way you can meet SID requirements EO, or missed EO in gradient, unless you have a special procedure designed, or limit your weights.
again, I have data for 0.0% 2nd segment OEI operation)
Again, nothing in procedure design criteria references EO, either in missed or departure.
Last edited by FlightPathOBN; 20th Jul 2012 at 02:05.
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@FE Hoppy – I’m not sure I understand what you asked/stated but if you are not limited by the AFM or regulation, then it is legal. Data will not be in the AFM unless it is approved during the type certification process which is done in compliance with Part 23/25.
(*AFMs may actually have unapproved data but it must be clearly notated. For example, I have overweight landing Vref speeds but that does not authorize me to plan overweight landings.)
@HazelNutz39 – there is no requirement in Part 25 that a manufacturer provide operational data that exceeds any particular climb gradient. Certification rules (Part 25) say that the manufacturer will provide each WAT within the operational limits of the aircraft that produce a climb gradient of 2.4% OEI (two engine acft). In other words, it’s not contrary to Part 25 for manufacturers to publish a WAT for a 0.4% second segment OEI climb, nor is it contrary to provide data for a 14% second segment OEI climb.
I completely agree, you must comply with what is in the AFM (FAR 91.9) and MTOW, altitude limitations, temp limits (min and max), CG limits, Vne ect. Remember that performance charts are the laws of physics – simplified. If you configure an aircraft as per any performance chart, the aircraft CANT do anything else but deliver the numbers in the book.
As for 91.605, I agree you cant depart an airport that you don’t have performance data for (or is prohibited by the AFM), but Part 91 does not specify climb gradients after 35’. I other words, I am in compliance (legal), if I have a WAT in my AFM for 0.4% OEI climb, and I can legally depart. Consider the implications of 25.117.
@john_tullamarine I agree, the AFM is created for the sole purpose of ensuring that the design limitations are clearly outlined. FAR 91.9 then elevates the guidance in the AFM to that equal to a regulation. There will not be anything in an AFM that is contrary to a certification regulation (the FAA will not approve it).
AFMs do not specifically require a minimum climb gradient. Every AFM will have the data required by FAR25.121 and most will have more data but no AFM will have less. If you need a particular OEI gradient, the performance section will tell you what WAT will give you your requested climb performance. The OEI climb performance you require may be due to TERPS, OpSpecs, 121/135 regulation, DP, noise or JAA/CAA. If in the course of trying to obtain the desired climb performance, you “run off the chart” or data is not provided for your desired OEI climb then, yes, you must find another way. You are allowed to interpolate but cannot extrapolate.
I am interested as to what the lowest OEI climb gradient is published in your AFM. MGTOW, 40C and 4200 msl will result in 0.0% OEI climb in mine.
@FlightPathOBN – FAR 23 and 25 are aircraft design certification requirements and FAR 25.121 is titled Climb: One- Engine Inoperative. All most all of my climb charts are OEI (in fact all engine operating charts are the issue). There are several companies out there specializing in custom departure procedures (and they are affordable). We reference them for 90% of our take offs and brief the alternate departure procedures in about 25% of our operations. We meet the SID climbs with OEI the rest of the time. As for MACG, we don’t often calculate that (but we should) and we have procedures to adjust our mins so that we can meet a MACG in places where it becomes critical (ASE in the summer for example).
(*AFMs may actually have unapproved data but it must be clearly notated. For example, I have overweight landing Vref speeds but that does not authorize me to plan overweight landings.)
@HazelNutz39 – there is no requirement in Part 25 that a manufacturer provide operational data that exceeds any particular climb gradient. Certification rules (Part 25) say that the manufacturer will provide each WAT within the operational limits of the aircraft that produce a climb gradient of 2.4% OEI (two engine acft). In other words, it’s not contrary to Part 25 for manufacturers to publish a WAT for a 0.4% second segment OEI climb, nor is it contrary to provide data for a 14% second segment OEI climb.
I completely agree, you must comply with what is in the AFM (FAR 91.9) and MTOW, altitude limitations, temp limits (min and max), CG limits, Vne ect. Remember that performance charts are the laws of physics – simplified. If you configure an aircraft as per any performance chart, the aircraft CANT do anything else but deliver the numbers in the book.
As for 91.605, I agree you cant depart an airport that you don’t have performance data for (or is prohibited by the AFM), but Part 91 does not specify climb gradients after 35’. I other words, I am in compliance (legal), if I have a WAT in my AFM for 0.4% OEI climb, and I can legally depart. Consider the implications of 25.117.
@john_tullamarine I agree, the AFM is created for the sole purpose of ensuring that the design limitations are clearly outlined. FAR 91.9 then elevates the guidance in the AFM to that equal to a regulation. There will not be anything in an AFM that is contrary to a certification regulation (the FAA will not approve it).
AFMs do not specifically require a minimum climb gradient. Every AFM will have the data required by FAR25.121 and most will have more data but no AFM will have less. If you need a particular OEI gradient, the performance section will tell you what WAT will give you your requested climb performance. The OEI climb performance you require may be due to TERPS, OpSpecs, 121/135 regulation, DP, noise or JAA/CAA. If in the course of trying to obtain the desired climb performance, you “run off the chart” or data is not provided for your desired OEI climb then, yes, you must find another way. You are allowed to interpolate but cannot extrapolate.
I am interested as to what the lowest OEI climb gradient is published in your AFM. MGTOW, 40C and 4200 msl will result in 0.0% OEI climb in mine.
@FlightPathOBN – FAR 23 and 25 are aircraft design certification requirements and FAR 25.121 is titled Climb: One- Engine Inoperative. All most all of my climb charts are OEI (in fact all engine operating charts are the issue). There are several companies out there specializing in custom departure procedures (and they are affordable). We reference them for 90% of our take offs and brief the alternate departure procedures in about 25% of our operations. We meet the SID climbs with OEI the rest of the time. As for MACG, we don’t often calculate that (but we should) and we have procedures to adjust our mins so that we can meet a MACG in places where it becomes critical (ASE in the summer for example).
The plane MUST be operated within its certification rules which includes the WAT limit of 2.4% climb gradient to a minimum of 400' AFE. You cannot blow off the certification standards by saying you are FAR 91.
GF
GF
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Skky,
hmmmm...my favorite to use is a company called Operations Based Navigation!
There are only a few airlines which have OEI procedures in the FMC, and they have been associated with RNP procedure designs. There is one for Burbank, so they didnt have to limit weights on hot days...
and I am glad that you realize that SID, or the missed approach on a plate is not OEI.
I mean you could use them, as long as you calc out OEI performance with temp, and unload the aircraft!
There are several companies out there specializing in custom departure procedures (and they are affordable).
There are only a few airlines which have OEI procedures in the FMC, and they have been associated with RNP procedure designs. There is one for Burbank, so they didnt have to limit weights on hot days...
and I am glad that you realize that SID, or the missed approach on a plate is not OEI.
I mean you could use them, as long as you calc out OEI performance with temp, and unload the aircraft!
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@4dogs – Yes.. Part 91 operations in a jet aircraft
@FlightPlathOBN – I use Aircraft Performance Group Welcome to Aircraft Performance Group They can do runway perf for any airport (they haven’t failed me yet).. they just need your aircraft loaded into their database. They often use the same flight path as the published Departure Procedure but because their lateral clearance is less than TERPS, you can depart heavier (that will start another conversation I'm sure). The advantage is you already have it in your FMS. When they provide a completely new procedure, it is not too difficult to plan/program into an FMS. We have company procedures that outline how this is done.
Its not so much of a “realization” as it is just reading it. TERPS says quite clearly that it is not OEI. Furthermore OEI is an Emergency (at least in my book) and continuing on a DP and trying to meet a climb requirement when there is a perfectly viable escape route available is – in my book – the very definition of careless and reckless.
You are exactly right, about offloading… If I may paraphrase the whole thing, you essentially need a “Plan B” to be legal. Plan B may be an escape procedure, it may be flying the DP at a weight that allows you to meet the climb requirements OEI, or it may be fly over the ocean until you can climb high enough to turn around. As long as you can prove your “Plan B” is viable (and you can climb to 35’), you are legal. Many operators choose to offload in order to comply with the DP OEI. Nothing wrong with that – other than you may not have actually been required to do that (again, from a purely legal perspective). (and I’m sure you meant Landing Climb).
@galaxy flyer – can you show me where in the regulations (Part 91 operation) where it says a pilot must operate an aircraft with a 2.4% to 400”? Psalm and verse if you please.
Thanks
@FlightPlathOBN – I use Aircraft Performance Group Welcome to Aircraft Performance Group They can do runway perf for any airport (they haven’t failed me yet).. they just need your aircraft loaded into their database. They often use the same flight path as the published Departure Procedure but because their lateral clearance is less than TERPS, you can depart heavier (that will start another conversation I'm sure). The advantage is you already have it in your FMS. When they provide a completely new procedure, it is not too difficult to plan/program into an FMS. We have company procedures that outline how this is done.
Its not so much of a “realization” as it is just reading it. TERPS says quite clearly that it is not OEI. Furthermore OEI is an Emergency (at least in my book) and continuing on a DP and trying to meet a climb requirement when there is a perfectly viable escape route available is – in my book – the very definition of careless and reckless.
You are exactly right, about offloading… If I may paraphrase the whole thing, you essentially need a “Plan B” to be legal. Plan B may be an escape procedure, it may be flying the DP at a weight that allows you to meet the climb requirements OEI, or it may be fly over the ocean until you can climb high enough to turn around. As long as you can prove your “Plan B” is viable (and you can climb to 35’), you are legal. Many operators choose to offload in order to comply with the DP OEI. Nothing wrong with that – other than you may not have actually been required to do that (again, from a purely legal perspective). (and I’m sure you meant Landing Climb).
@galaxy flyer – can you show me where in the regulations (Part 91 operation) where it says a pilot must operate an aircraft with a 2.4% to 400”? Psalm and verse if you please.
Thanks
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Originally Posted by Galaxy flyer
The plane MUST be operated within its certification rules which includes the WAT limit of 2.4% climb gradient to a minimum of 400' AFE.
Skky is probably a 'troll' who knows perfectly well that it's illegal to operate an airplane outside its operating limitations.
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herewith is your psalm and verse.... FAR 25.121 Airworthiness
Mutt
(b) Takeoff; landing gear retracted. In the takeoff configuration existing at the point of the flight path at which the landing gear is fully retracted, and in the configuration used in §25.111 but without ground effect:
(1) The steady gradient of climb may not be less than 2.4 percent for two-engine airplanes, 2.7 percent for three-engine airplanes, and 3.0 percent for four-engine airplanes, at V2with:
(1) The steady gradient of climb may not be less than 2.4 percent for two-engine airplanes, 2.7 percent for three-engine airplanes, and 3.0 percent for four-engine airplanes, at V2with:
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Mutt:
In the U.S. that transfers to the applicable commercial flight operations regulations. But, for the non-commercial operator flying a Part 25 aircraft it does not. Part 91 does require the non-commercial operator to calculate the balanced field for takeoff but once airborne there is no specific requirement to make good the Part 25 takeoff flight path, all engines operating or OEI. With all engines operating he is bound, though, by a SID climb gradient as I would be in my Part 23 bugsmasher.
herewith is your psalm and verse.... FAR 25.121 Airworthiness
Last edited by aterpster; 26th Jul 2012 at 14:24.
Ok, skyy, your point might be true, BUT why would any responsible operator of Part 25 aircraft NOT try to achieve the highest standards by using appropriate runway analysis for departure? We, and a number of operators, use APG or equal on all departures.
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Part 91 requires you to operate in accordance with the flight manual limitations.
Below is a typical AFM from a Part 25 a/c.
2. MAXIMUM ALLOWABLE TAKE-OFF WEIGHT
The maximum allowable take-off weight is limited by the most restrictive of the following:
• Maximum approved take-off weight
(Refer to Chapter 2; LIMITATIONS – STRUCTURAL WEIGHT),
• Runway length available,
• Climb requirements,
• Obstacle clearance requirements,
(First, verify if the second segment of the take−off flight path extends beyond a pressure
height of 1,500 feet above the airport and consider if potential adjustments are to be made.)
• Maximum demonstrated brake energy,
• Maximum tire speed,
• Wheel brake cooling limitations
(Refer to PERFORMANCE – TURN-AROUND TIME – Cooling of Wheels, Brakes and Tires,
in this chapter).
Note that obstacles are in there as well.
It seems pretty unequivocal to me - which bit of Maximum Allowable Takeoff Weight do people have a problem with?
Apart from the legal considerations, why would anyone not want to take the climb performance into account? A 2.4% gradient with no obstacles or 35 feet clearance if there is seems pretty sphincter tightening to me
Added to which, in my book I'm being paid to keep the boss safe - and he thinks so too. He would probably be mightily unimpressed (= me fired) if he though I was gambling with his and his family's safety.
Below is a typical AFM from a Part 25 a/c.
2. MAXIMUM ALLOWABLE TAKE-OFF WEIGHT
The maximum allowable take-off weight is limited by the most restrictive of the following:
• Maximum approved take-off weight
(Refer to Chapter 2; LIMITATIONS – STRUCTURAL WEIGHT),
• Runway length available,
• Climb requirements,
• Obstacle clearance requirements,
(First, verify if the second segment of the take−off flight path extends beyond a pressure
height of 1,500 feet above the airport and consider if potential adjustments are to be made.)
• Maximum demonstrated brake energy,
• Maximum tire speed,
• Wheel brake cooling limitations
(Refer to PERFORMANCE – TURN-AROUND TIME – Cooling of Wheels, Brakes and Tires,
in this chapter).
Note that obstacles are in there as well.
It seems pretty unequivocal to me - which bit of Maximum Allowable Takeoff Weight do people have a problem with?
Apart from the legal considerations, why would anyone not want to take the climb performance into account? A 2.4% gradient with no obstacles or 35 feet clearance if there is seems pretty sphincter tightening to me
Added to which, in my book I'm being paid to keep the boss safe - and he thinks so too. He would probably be mightily unimpressed (= me fired) if he though I was gambling with his and his family's safety.