Go around, thrust reduction altitude oei
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Go around, thrust reduction altitude oei
we are an A330 Operator and airbus and co policy for Go around is, TOGA to 1500ft then accelerate. For two engine scenario my view is this is correct but if the MAP procedure stipulates a higher for climb then if you can achieve this within 5 mins TOGA great. if not and you continue to climb higher at MCT then accel then climb again (in two engine accel I think you are energy sharing and will still be climbing.
For OEI I do not believe that you can guarantee you will make the required climb gradient required (std 2.1%, 2.5% )
As MAP procedures i believe are designed for AEO.
I do produce tables for our crew that show OEI Go Around mass limits/ capability for a range of climb gradients -v- altitude with factors for non std pressure, temp and air con/anti ice.
However even if this showed we can achieve (e.g) 2.5% climb at 5000ft at 40c with a weight of 200t, it does not guarantee we can continue to climb at this gradient to the required MAP altitude without busting the 10minute (OEI) limit..after which we would be at MCT and climb rate would be reduced and may not meet the requirements of the MAP procedure.
We have carefully designed Engine out Procedures for take-off which our contractor advises should also be used for OEI Go Around. This makes sense to me as they have analysed the terrain and obstacles after DER ( no turns permitted before DER) and will take you safely on one engine to a HP over a Navaid. Although the aircraft is GO around and not take-off, it will still be using TOGA (and its limits) will possibly be higher, >200ft.
It would seem our some are teaching, for OEI Go Around, that you should climb to 1500ft and then level off accel and then continue climb but follow the MAP, this is fraught with risk for me as it does not follow the MAP as designed and the overall gradient (with a accel segment included) may not meet the required gradient.
I understand others state you should climb until reaching the MAP altitude, my only concern here is that we may reach the 10mins TOGA limitation before we reach MAP altitude and then either be accelerating or climbing at MCT, both of which would have an inferior climb rate and may not meet the std required.
An accel/level off segment for AEO does not concern me as we achieve a climb gradient of >10% even at heavy weights and the accel segment is energy sharing so there is still climb. However for OEI our climb rate is not a great deal higher then std and would be reduced somewhat after TOGA limits are used.
Hope that makes some sense, I have been waffling somewhat, but really would appreciate thoughts on this as soon as possible
For OEI I do not believe that you can guarantee you will make the required climb gradient required (std 2.1%, 2.5% )
As MAP procedures i believe are designed for AEO.
I do produce tables for our crew that show OEI Go Around mass limits/ capability for a range of climb gradients -v- altitude with factors for non std pressure, temp and air con/anti ice.
However even if this showed we can achieve (e.g) 2.5% climb at 5000ft at 40c with a weight of 200t, it does not guarantee we can continue to climb at this gradient to the required MAP altitude without busting the 10minute (OEI) limit..after which we would be at MCT and climb rate would be reduced and may not meet the requirements of the MAP procedure.
We have carefully designed Engine out Procedures for take-off which our contractor advises should also be used for OEI Go Around. This makes sense to me as they have analysed the terrain and obstacles after DER ( no turns permitted before DER) and will take you safely on one engine to a HP over a Navaid. Although the aircraft is GO around and not take-off, it will still be using TOGA (and its limits) will possibly be higher, >200ft.
It would seem our some are teaching, for OEI Go Around, that you should climb to 1500ft and then level off accel and then continue climb but follow the MAP, this is fraught with risk for me as it does not follow the MAP as designed and the overall gradient (with a accel segment included) may not meet the required gradient.
I understand others state you should climb until reaching the MAP altitude, my only concern here is that we may reach the 10mins TOGA limitation before we reach MAP altitude and then either be accelerating or climbing at MCT, both of which would have an inferior climb rate and may not meet the std required.
An accel/level off segment for AEO does not concern me as we achieve a climb gradient of >10% even at heavy weights and the accel segment is energy sharing so there is still climb. However for OEI our climb rate is not a great deal higher then std and would be reduced somewhat after TOGA limits are used.
Hope that makes some sense, I have been waffling somewhat, but really would appreciate thoughts on this as soon as possible
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The OEI procedure should have been designed to take into account the engine TOGA limitations.
Are you talking about a specific procedure, or are you speaking in general?
The danger with using the DEP procedure is that it is designed differently than a missed approach. The missed approach OEI procedure will set the DA based on the obstacles in the approach, and OEI performance. While an all engine missed, such with a standard approach procedure may have a 250 HAT, the procedure with an OEI missed may have a much higher DA.
Typically a DEP does not have a hold as part of the design, but a missed approach will likely have a place to hold. Getting to the hold pattern OEI is accounted for in that design.
Hopefully, that helps a bit.
Are you talking about a specific procedure, or are you speaking in general?
The danger with using the DEP procedure is that it is designed differently than a missed approach. The missed approach OEI procedure will set the DA based on the obstacles in the approach, and OEI performance. While an all engine missed, such with a standard approach procedure may have a 250 HAT, the procedure with an OEI missed may have a much higher DA.
Typically a DEP does not have a hold as part of the design, but a missed approach will likely have a place to hold. Getting to the hold pattern OEI is accounted for in that design.
Hopefully, that helps a bit.
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OpsRoomJunkie,
Perhaps you could calculate the altitude that can be reached within the 10 minute limit OEI? It should be scheduled in the AFM for the takeoff case, which may be conservative for the GA case.
Perhaps you could calculate the altitude that can be reached within the 10 minute limit OEI? It should be scheduled in the AFM for the takeoff case, which may be conservative for the GA case.
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Hi Ops_Room_Junkie,
What you have described is what we do before each approach using Computer software to calculate our OEI GA gradient using different flap settings and the latest Met data.
Since approach plates are now PANS OPS 4 there is no allowance for the level acceleration.
Some approaches may be impossible (e.g. NAP ILS Z RW 06) requires a gradient of about 5% to 7,000 ft. Others like ZRH may require a different DA.
I assumed everyone did the calculations either using computer software or paper tables like we did in the old days.
What you have described is what we do before each approach using Computer software to calculate our OEI GA gradient using different flap settings and the latest Met data.
Since approach plates are now PANS OPS 4 there is no allowance for the level acceleration.
Some approaches may be impossible (e.g. NAP ILS Z RW 06) requires a gradient of about 5% to 7,000 ft. Others like ZRH may require a different DA.
I assumed everyone did the calculations either using computer software or paper tables like we did in the old days.
Last edited by rudderrudderrat; 12th Sep 2013 at 06:33. Reason: Addition of Blind Pew's post
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Go around, thrust reduction altitude oei
Hi Ruddercat,
The LPC calculates only a singular OEI macg, presumably at a nominal TCH or 200ft I imagine. What will the macg be after 10min at toga? The LPC does not know about msa/missed approach alt, so it can only produce a singular macg. This is wrong in my opinion.
Pans ops (4 onwards) requires 2.5% macg (geometrically) until obstacle clearance is covered by other means (msa/chart note/missed app alt). A singular macg of 2.5% at apt elevation/tch (or whatever the ref is) does not meet this requirement and only expresses instantaneous macg, not the geometric profile able to achieve.
It's almost like if the airbus lpc is meant to calculate (albeit modifiable) g/a climb gradient as required by cs-25 only: 2.1% capability at G/A rather than the operational reqds of pans-ops!
Any thoughts?
The LPC calculates only a singular OEI macg, presumably at a nominal TCH or 200ft I imagine. What will the macg be after 10min at toga? The LPC does not know about msa/missed approach alt, so it can only produce a singular macg. This is wrong in my opinion.
Pans ops (4 onwards) requires 2.5% macg (geometrically) until obstacle clearance is covered by other means (msa/chart note/missed app alt). A singular macg of 2.5% at apt elevation/tch (or whatever the ref is) does not meet this requirement and only expresses instantaneous macg, not the geometric profile able to achieve.
It's almost like if the airbus lpc is meant to calculate (albeit modifiable) g/a climb gradient as required by cs-25 only: 2.1% capability at G/A rather than the operational reqds of pans-ops!
Any thoughts?
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Hi Open Des,
Since the default EO Acceleration Altitude is 1500ft AAL, I've assumed the macg calculated is the average value up to that AA.
A higher AA would need to be considered carefully, and if there's any doubt, then the best option would be to fly the EO procedure for the take off case and advise ATC accordingly. Fortunately, most of us will not see this problem during our entire aviation career.
I can remember a Trident in the 70s doing an EO GA from Madrid in summer and it didn't make 2.1% climb gradient. Fortunately they were VMC and managed to avoid all obstacles. See post 52 by Blind Pew here
The problem was grasped by our performance people who analysed all our Destination and Alternate airfields and produced tables of planned maximum Landing weights for each runway with WAT limits.
Since the default EO Acceleration Altitude is 1500ft AAL, I've assumed the macg calculated is the average value up to that AA.
A higher AA would need to be considered carefully, and if there's any doubt, then the best option would be to fly the EO procedure for the take off case and advise ATC accordingly. Fortunately, most of us will not see this problem during our entire aviation career.
I can remember a Trident in the 70s doing an EO GA from Madrid in summer and it didn't make 2.1% climb gradient. Fortunately they were VMC and managed to avoid all obstacles. See post 52 by Blind Pew here
The problem was grasped by our performance people who analysed all our Destination and Alternate airfields and produced tables of planned maximum Landing weights for each runway with WAT limits.
Last edited by rudderrudderrat; 12th Sep 2013 at 06:35. Reason: Addition of Blind Pew's post
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Unfortunately - but I suspect generally - the bulk of the Industry doesn't consider the potential for CFIT hazards in the miss, especially OEI.
The more enlightened ops eng folk will be into the books to do some sums and provide useful data for their front seat colleagues .. in the manner described by RRR.
One caveat, though, is that eye-balling an OEI escape amongst the rocks and tulips is not a repeatably doable exercise - and is extremely fraught with danger - due both to the very shallow gradients achievable and the practical difficulty seeing what's going on about the aircraft with a nose high pitch attitude .. close to impossible in my view.
One hopes that this thread develops into a robust discussion of ways and means to achieve that end.
The more enlightened ops eng folk will be into the books to do some sums and provide useful data for their front seat colleagues .. in the manner described by RRR.
One caveat, though, is that eye-balling an OEI escape amongst the rocks and tulips is not a repeatably doable exercise - and is extremely fraught with danger - due both to the very shallow gradients achievable and the practical difficulty seeing what's going on about the aircraft with a nose high pitch attitude .. close to impossible in my view.
One hopes that this thread develops into a robust discussion of ways and means to achieve that end.
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Go around, thrust reduction altitude oei
Hi ruddercat,
Imagine the following situation:
-pans-ops 4 chart required 4% for missed app
-LPC says the a/c can do 4,01% (but up to what altitude remains the question!!!)
-MSA is 6000ft, missed app alt is 5000ft, no chart exception (e.g. France: no level accel prior to .....)
-only way to guarantee obstacle clearance is to achieve mnm 4% up to 5000ft
-the LPC says the a/c can achieve 4,01% but can it still guarantee 4% at 5000ft???
The answer is NO! And this is a serious deficiency in our performance considerations!
The LPC landing performance module should include an input for "level acceleration altitude". G/A performance should not stop at 1500ft or with a singular MACG obtained for a nominal height! It should be assessed geometrically up to msa/missed app alt as in line with the assumptions of pans-ops!
Pans-ops 3 previously catered for a 6nm level accel segment at 800ft. This is gone now and is missed by quite a few operators.
Another point:
There is a lot of confusion with regards to 2.1% vs 2.5% macg!
They are two different things!
2.1% is a certification requirement as per EASA CS-25, previously JAR-25. We don't have to worry about that one.
2.5% is an operational requirement as per PANS-OPS to guarantee obstacle clearance! If a chart does not say otherwise: 2.5% is the absolute minimum!
Best regards
Imagine the following situation:
-pans-ops 4 chart required 4% for missed app
-LPC says the a/c can do 4,01% (but up to what altitude remains the question!!!)
-MSA is 6000ft, missed app alt is 5000ft, no chart exception (e.g. France: no level accel prior to .....)
-only way to guarantee obstacle clearance is to achieve mnm 4% up to 5000ft
-the LPC says the a/c can achieve 4,01% but can it still guarantee 4% at 5000ft???
The answer is NO! And this is a serious deficiency in our performance considerations!
The LPC landing performance module should include an input for "level acceleration altitude". G/A performance should not stop at 1500ft or with a singular MACG obtained for a nominal height! It should be assessed geometrically up to msa/missed app alt as in line with the assumptions of pans-ops!
Pans-ops 3 previously catered for a 6nm level accel segment at 800ft. This is gone now and is missed by quite a few operators.
Another point:
There is a lot of confusion with regards to 2.1% vs 2.5% macg!
They are two different things!
2.1% is a certification requirement as per EASA CS-25, previously JAR-25. We don't have to worry about that one.
2.5% is an operational requirement as per PANS-OPS to guarantee obstacle clearance! If a chart does not say otherwise: 2.5% is the absolute minimum!
Best regards
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2.5 is also the required grad for missed with DH less than 200' I think this is moved to CS AWO these days but was in CS 25 at one point.
do a take off calc for the runway you plan to land on using appropriate flap setting, if you're landing above max TOW fly the EOSID bob's your uncle :-)
do a take off calc for the runway you plan to land on using appropriate flap setting, if you're landing above max TOW fly the EOSID bob's your uncle :-)
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we are an A330 Operator and airbus and co policy for Go around is, TOGA to 1500ft then accelerate. For two engine scenario my view is this is correct
To broaden the discussion a little: there are MAA's of 2000' agl. Applying full TOGA until 1500' will make the level off quite a challenge, especially in manual flight. What thrust does a G.A. from a multiple AP approach give? In B737's it's generally about 90% or <2000fpm. This is enough and controllable. IMHO full TOGA, all engines, is a scenario where there is too much power and I wonder if the a/c is under full control as it races skywards. If you can do a reduced thrust takeoff from well down the rwy then surely you can do a reduced G.A safely, allowing for all the gradient %'s as discussed.
To broaden the discussion a little: there are MAA's of 2000' agl. Applying full TOGA until 1500' will make the level off quite a challenge, especially in manual flight. What thrust does a G.A. from a multiple AP approach give? In B737's it's generally about 90% or <2000fpm. This is enough and controllable. IMHO full TOGA, all engines, is a scenario where there is too much power and I wonder if the a/c is under full control as it races skywards. If you can do a reduced thrust takeoff from well down the rwy then surely you can do a reduced G.A safely, allowing for all the gradient %'s as discussed.
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Go around, thrust reduction altitude oei
You are missing the point entirely. We are talking about OEI g/a and the application of PANS-OPS criteria.
Btw
AEO you can reduce to CLB thrust after FMAs have been read and a/c is going up to mitigate against alt overshoot and to slow things down a bit.
Btw
AEO you can reduce to CLB thrust after FMAs have been read and a/c is going up to mitigate against alt overshoot and to slow things down a bit.
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Hi OPEN DES,
The explanation notes in Performance, Go Around, General, Procedure say:
"According to airport pressure altitude and temperature determine if the slats/flaps setting must be restricted as a function of the landing weight, in order to meet the go around gradient requirement of 2.1 %.
Establish the final approach configuration with one more step of flaps. If the approach is interrupted, retract the flaps by one step during the go-around.
In case of category II approach, JAR-OPS requires a regulatory approach climb gradient of 2.5 % to be maintained.
Use the tables for CAT II approach to determine the maximum approach climb limiting weight according to airport pressure altitude and temperature."
I have always assumed the published gradient must be valid from airport level an an AA of 1500ft (the default AA before amendment).
If you look at the published tables in: Go Around, ACG-Approach Climb limiting for various gradients, weights and airfield Altitudes - one can see that in order to maintain the gradient, the weight must be reduced by about 1 ton per 1,000 ft increase in airport Altitude. (for A320)
Therefore to answer
- then no it can't.
I guess you would have to enter the LPC calculation with an assumed weight of about 1 ton heavier for every thousand feet your AA is above 1500ft AAL. (for A320)
The explanation notes in Performance, Go Around, General, Procedure say:
"According to airport pressure altitude and temperature determine if the slats/flaps setting must be restricted as a function of the landing weight, in order to meet the go around gradient requirement of 2.1 %.
Establish the final approach configuration with one more step of flaps. If the approach is interrupted, retract the flaps by one step during the go-around.
In case of category II approach, JAR-OPS requires a regulatory approach climb gradient of 2.5 % to be maintained.
Use the tables for CAT II approach to determine the maximum approach climb limiting weight according to airport pressure altitude and temperature."
I have always assumed the published gradient must be valid from airport level an an AA of 1500ft (the default AA before amendment).
If you look at the published tables in: Go Around, ACG-Approach Climb limiting for various gradients, weights and airfield Altitudes - one can see that in order to maintain the gradient, the weight must be reduced by about 1 ton per 1,000 ft increase in airport Altitude. (for A320)
Therefore to answer
the LPC says the a/c can achieve 4,01% but can it still guarantee 4% at 5000ft???
I guess you would have to enter the LPC calculation with an assumed weight of about 1 ton heavier for every thousand feet your AA is above 1500ft AAL. (for A320)
Last edited by rudderrudderrat; 12th Sep 2013 at 20:41.
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Hi Rudderrat,
Thanks for your reply.
The FCOM explanatory note is outdated and refers to an obsolete document (JAR-OPS). Let´s assume we talk about the A320 family here.
1.
EASA Air Ops, part CAT does not make any provisions for Performance class A in G/A for AEO nor OEI.
2.
EASA CS-25 contains certification specifications for large aeroplanes and specifies a steady 2.1% for twins OEI. As CS-25 is for certification it is of no direct relevance to our commercial air transport, day to day operation. However it seems that Airbus has included tables in FCOM to show compliance to these certification standards. These tables are of no operational value as we need to ensure compliance with PANS-OPS (2.5% MACG) whenever we fly an instrument approach.
3.
For a DH less than 200ft (CAT2 upwards) EASA CS-AWO states that the aircraft must be able to clear the obstacles as specified in PANS-OPS. Therefore CS-AWO mentions that a WAT table for a 2.5% MACG must feature in the airplane AFM. Again Airbus shows compliance by including a ¨CAT 2 - 2.5% MACG¨ table in FCOM, this coincides with the PANS-OPS requirement even when doing a CAT1 or NPA! (Confused already?)
4.
As an operator we don´t have to worry about CS´s as these are for the manufacturer. As EASA Air Ops does not specify any requirements we only need to ensure compliance with PANS-OPS.
5.
Your method of applying a 1t penalty for every 1000ft above nominal EOAA might be a fair approximation but is hardly academic. Also we are not interested in the singular MACG at EOAA. We need a 2.5% geometric MACG, which is something different. We treat take off performance with great accuracy, why should we treat G/A performance any different?
6.
Airbus only recently changed the default MACG in the LPC from 2.1% to 2.5% which is really strange as the 2.1% has only ever been a certification requirement and never an operational requirement!
7.
Airbus should change the LPC landing module to have an EOAA input-field. This would be for the purpose of defining a geometric MACG up to any EOAA. If unable to comply we should have an ¨emergency turn, EOSID¨. Alternatively we could revert to a constructed ¨emergency turn/EOSID¨ whenever OEI in the same spirit of some operators´ take-off performance.
8.
We consider an engine to fail during any moment of the take-off. However for G/A we allow AEO thr reduction/accel alt routinely to be below our minimum G/A EOAA (MSA/missed app alt). Surely once thrust is reduced and or acceleration has begun we are commited to the AEO scenario. What if the engine fails at this moment? We´ll have to level-off to accelerate and possibly infringe our 2.5% geometric MACG. This is inconsistent with what we do on take-off: normally any prudent operator will not allow EOAA to be higher than AEO AA.
9.
A320 QRH overweight landing checklist includes a G/A WAT table, presumably for 2.1% gradient. This is of no use, unless you intend to do a visual approach anytime you´re overweight.
.
Just my thoughts guys. Happy to be corrected.
Best regards
Thanks for your reply.
The FCOM explanatory note is outdated and refers to an obsolete document (JAR-OPS). Let´s assume we talk about the A320 family here.
1.
EASA Air Ops, part CAT does not make any provisions for Performance class A in G/A for AEO nor OEI.
2.
EASA CS-25 contains certification specifications for large aeroplanes and specifies a steady 2.1% for twins OEI. As CS-25 is for certification it is of no direct relevance to our commercial air transport, day to day operation. However it seems that Airbus has included tables in FCOM to show compliance to these certification standards. These tables are of no operational value as we need to ensure compliance with PANS-OPS (2.5% MACG) whenever we fly an instrument approach.
3.
For a DH less than 200ft (CAT2 upwards) EASA CS-AWO states that the aircraft must be able to clear the obstacles as specified in PANS-OPS. Therefore CS-AWO mentions that a WAT table for a 2.5% MACG must feature in the airplane AFM. Again Airbus shows compliance by including a ¨CAT 2 - 2.5% MACG¨ table in FCOM, this coincides with the PANS-OPS requirement even when doing a CAT1 or NPA! (Confused already?)
4.
As an operator we don´t have to worry about CS´s as these are for the manufacturer. As EASA Air Ops does not specify any requirements we only need to ensure compliance with PANS-OPS.
5.
Your method of applying a 1t penalty for every 1000ft above nominal EOAA might be a fair approximation but is hardly academic. Also we are not interested in the singular MACG at EOAA. We need a 2.5% geometric MACG, which is something different. We treat take off performance with great accuracy, why should we treat G/A performance any different?
6.
Airbus only recently changed the default MACG in the LPC from 2.1% to 2.5% which is really strange as the 2.1% has only ever been a certification requirement and never an operational requirement!
7.
Airbus should change the LPC landing module to have an EOAA input-field. This would be for the purpose of defining a geometric MACG up to any EOAA. If unable to comply we should have an ¨emergency turn, EOSID¨. Alternatively we could revert to a constructed ¨emergency turn/EOSID¨ whenever OEI in the same spirit of some operators´ take-off performance.
8.
We consider an engine to fail during any moment of the take-off. However for G/A we allow AEO thr reduction/accel alt routinely to be below our minimum G/A EOAA (MSA/missed app alt). Surely once thrust is reduced and or acceleration has begun we are commited to the AEO scenario. What if the engine fails at this moment? We´ll have to level-off to accelerate and possibly infringe our 2.5% geometric MACG. This is inconsistent with what we do on take-off: normally any prudent operator will not allow EOAA to be higher than AEO AA.
9.
A320 QRH overweight landing checklist includes a G/A WAT table, presumably for 2.1% gradient. This is of no use, unless you intend to do a visual approach anytime you´re overweight.
.Just my thoughts guys. Happy to be corrected.
Best regards
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Hi OPEN DES,
Too many questions for me to answer straight off but a couple of thoughts:
1) You do many take offs, but few GAs, therefore the chance of an engine failure during the GA is much less than during the take off.
2) If you suffer an engine failure after AA on the GA, then your all engine climb out would have been much bigger than the minimum required gradient.
3) We have the luxury of being able to choose nearest "suitable diversion airfield" after an engine failure - so choose wisely.
Too many questions for me to answer straight off but a couple of thoughts:
However for G/A we allow AEO thr reduction/accel alt routinely to be below our minimum G/A EOAA (MSA/missed app alt). Surely once thrust is reduced and or acceleration has begun we are commited to the AEO scenario. What if the engine fails at this moment?
2) If you suffer an engine failure after AA on the GA, then your all engine climb out would have been much bigger than the minimum required gradient.
3) We have the luxury of being able to choose nearest "suitable diversion airfield" after an engine failure - so choose wisely.
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Hi Rudderrat,
I appreciate your points and know them very well. I am just surprised at the fact that we choose not to treat the G/A with the same academicism as the take-off.
Point taken. But again, this is hardly academic. It´s the equivalent of saying let´s use 140-140-145, flex 50 on take-off everyday. We know that this will work in 99.9999999% of the cases (as long as the engine doesnt fail) but it´s simply not the way we have chosen to treat performance on take-off. Why should it be any different on G/A. Either we go all the way, or we shouldn´t bother at all. Even an engine failure in cruise is considered at all times, on all enroute segments. And this whilst a G/A is at low altitude (high thrust setting, birdstrikes, weather etc.) and arguably more likely to occur.
I appreciate your points and know them very well. I am just surprised at the fact that we choose not to treat the G/A with the same academicism as the take-off.
2) If you suffer an engine failure after AA on the GA, then your all engine climb out would have been much bigger than the minimum required gradient.
Last edited by OPEN DES; 12th Sep 2013 at 22:36.
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Some thoughts ...
The FCOM explanatory note is outdated and refers to an obsolete document (JAR-OPS).
Keep in mind that the certification stuff is frozen to whatever Design Standards applied to the aircraft. The present rules may not reflect what the aircraft can/can't do per the AFM.
As CS-25 is for certification it is of no direct relevance to our commercial air transport, day to day operation.
Now that's a very brave statement. The AFM is based on the certification requirements and the operator/pilot has to apply that to whatever the operational requirements may be .. that can present a difficulty from not much to very considerable ...
These tables are of no operational value as we need to ensure compliance with PANS-OPS (2.5% MACG) whenever we fly an instrument approach.
.. so just how do you go about maintaining compliance and better if terrain requires ?
As an operator we don´t have to worry about CS´s as these are for the manufacturer.
Can I suggest that a reputably operator invests considerable time and money in worrying about how the design standards fit into achieving operating requirements ?
for G/A we allow AEO thr reduction/accel alt routinely to be below our minimum G/A EOAA (MSA/missed app alt).
The reputable operator will have done the sums to make sure that a failure during the miss addresses the rocky bits and keeping an adequate distance from them ...
You do many take offs, but few GAs, therefore the chance of an engine failure during the GA is much less than during the take off.
Fair comment. However, while the Standards accept a finite risk, as pilots we should be somewhat interested in giving ourselves (and our pax) the best chance of survival .. hence achieving better than minimum standards all round ?
If you suffer an engine failure after AA on the GA, then your all engine climb out would have been much bigger than the minimum required gradient.
True .. but only relevant if the miss is straight ahead or the turns are constrained geographically and speed constrained to the critical window to keep the aircraft where the ops eng folks planned for it to be ..
We have the luxury of being able to choose nearest "suitable diversion airfield" after an engine failure - so choose wisely.
.. wise words.
I am just surprised at the fact that we choose not to treat the G/A with the same academicism as the take-off.
The reputable operator will do just that and has done so for many decades ..
The FCOM explanatory note is outdated and refers to an obsolete document (JAR-OPS).
Keep in mind that the certification stuff is frozen to whatever Design Standards applied to the aircraft. The present rules may not reflect what the aircraft can/can't do per the AFM.
As CS-25 is for certification it is of no direct relevance to our commercial air transport, day to day operation.
Now that's a very brave statement. The AFM is based on the certification requirements and the operator/pilot has to apply that to whatever the operational requirements may be .. that can present a difficulty from not much to very considerable ...
These tables are of no operational value as we need to ensure compliance with PANS-OPS (2.5% MACG) whenever we fly an instrument approach.
.. so just how do you go about maintaining compliance and better if terrain requires ?
As an operator we don´t have to worry about CS´s as these are for the manufacturer.
Can I suggest that a reputably operator invests considerable time and money in worrying about how the design standards fit into achieving operating requirements ?
for G/A we allow AEO thr reduction/accel alt routinely to be below our minimum G/A EOAA (MSA/missed app alt).
The reputable operator will have done the sums to make sure that a failure during the miss addresses the rocky bits and keeping an adequate distance from them ...
You do many take offs, but few GAs, therefore the chance of an engine failure during the GA is much less than during the take off.
Fair comment. However, while the Standards accept a finite risk, as pilots we should be somewhat interested in giving ourselves (and our pax) the best chance of survival .. hence achieving better than minimum standards all round ?
If you suffer an engine failure after AA on the GA, then your all engine climb out would have been much bigger than the minimum required gradient.
True .. but only relevant if the miss is straight ahead or the turns are constrained geographically and speed constrained to the critical window to keep the aircraft where the ops eng folks planned for it to be ..
We have the luxury of being able to choose nearest "suitable diversion airfield" after an engine failure - so choose wisely.
.. wise words.
I am just surprised at the fact that we choose not to treat the G/A with the same academicism as the take-off.
The reputable operator will do just that and has done so for many decades ..
In my outfit they survey each airfield we can fly into. Each airfield has a port page and this document details any different procedures required to meet obstacle clearance for T/O and G/A.
For example:--VHHH ILS 07L and 25R have proceedures required during Eng out to cater for terrain by modifying acceleration heights or tracking.
For example:--VHHH ILS 07L and 25R have proceedures required during Eng out to cater for terrain by modifying acceleration heights or tracking.
Last edited by nitpicker330; 13th Sep 2013 at 06:28.
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Hi John,
Aviation is all about risk management. The safest thing we can do with an aeroplane is leave it in the hangar - then we'll never be at risk.
If we adopt procedures which cater for the exceptionally low risk of having an engine failure during the GA, then we may run into other practical problems and risks.
e.g. Airbus don't have reduced GA power. The GA mode is only activated by the TLs hitting the micro switch at the full power detent. To keep the same procedure for all engines operating GAs as the EO procedure, would involve no thrust reduction nor acceleration until the first stop altitude. (as OPEN DES suggests).
Is that a wise procedure to adopt in busy airspace when ALT busts would be more likely?
If you suffer an engine failure after AA on the GA, then your all engine climb out would have been much bigger than the minimum required gradient.
True .. but only relevant if the miss is straight ahead or the turns are constrained geographically and speed constrained to the critical window to keep the aircraft where the ops eng folks planned for it to be ..
True .. but only relevant if the miss is straight ahead or the turns are constrained geographically and speed constrained to the critical window to keep the aircraft where the ops eng folks planned for it to be ..
If we adopt procedures which cater for the exceptionally low risk of having an engine failure during the GA, then we may run into other practical problems and risks.
e.g. Airbus don't have reduced GA power. The GA mode is only activated by the TLs hitting the micro switch at the full power detent. To keep the same procedure for all engines operating GAs as the EO procedure, would involve no thrust reduction nor acceleration until the first stop altitude. (as OPEN DES suggests).
Is that a wise procedure to adopt in busy airspace when ALT busts would be more likely?
I assume each of your destination airfields has a published EO proceedure for take off?
I may be missing something here, but in the event of a G/A following an EO approach, what is wrong with briefing and flying that profile rather than the published MAP?
I may be missing something here, but in the event of a G/A following an EO approach, what is wrong with briefing and flying that profile rather than the published MAP?
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In my outfit they survey each airfield we can fly into. Each airfield has a port page and this document details any different procedures required to meet obstacle clearance for T/O and G/A.
Salut ! Most places one can find existing survey data to suit but, if needs be .. it's a theodolite and kit over the shoulder and into the bush.
The reputable operators have always been thus.
Aviation is all about risk management.
Indeed, as is every activity for which we choose to be involved. However, risk assessment and management includes corporate risk .. hence the better operators invest in minimising the probability of the adverse publicity associated with a significant mishap.
If we adopt procedures which cater for the exceptionally low risk of having an engine failure during the GA, then we may run into other practical problems and risks.
If you are suggesting that we can ignore events with a rational risk assessment similar, for instance, to the Design Standards then I'm OK with that .. however, the corporate assessment would consider the cost/benefit as an input into whether the existing organisation can/should do things such as missed approach terrain performance assessment ...
To keep the same procedure for all engines operating GAs as the EO procedure, would involve no thrust reduction nor acceleration until the first stop altitude.
That's a simple approach to life and, often, not the optimal way to address the problem .. no reason (where practical) why the AEO procedure can't be analysed to provide for keys throughout to shift to an OEI procedure .. a case of balancing complexity against flight standards commonsense as well ... what I would be suggesting is that the other extreme of just blasting off into the AEO procedure without anything prearranged in the case one goes quiet is pretty silly.
In my ops engineering work in another life, my approach to strategy was very much coloured by my parallel time in the cockpit ....
Is that a wise procedure to adopt in busy airspace when ALT busts would be more likely?
That's just one more constraint for the ops eng and flight standards assessment to factor into the final procedure.
I assume each of your destination airfields has a published EO proceedure for take off?
That should be the case only where necessary. Generally, I would expect to see
(a) some runways with the AEO miss being fine OEI
(b) some runways would have a generic escape procedure for simplicity
(c) where terrain etc., dictates, the remainder ought to have detailed OEI analyses in a manner similar to takeoff work.
in the event of a G/A following an EO approach, what is wrong with briefing and flying that profile rather than the published MAP?
Indeed, it would be a tad silly to do otherwise if such is promulgated .. ?
Salut ! Most places one can find existing survey data to suit but, if needs be .. it's a theodolite and kit over the shoulder and into the bush.
The reputable operators have always been thus.
Aviation is all about risk management.
Indeed, as is every activity for which we choose to be involved. However, risk assessment and management includes corporate risk .. hence the better operators invest in minimising the probability of the adverse publicity associated with a significant mishap.
If we adopt procedures which cater for the exceptionally low risk of having an engine failure during the GA, then we may run into other practical problems and risks.
If you are suggesting that we can ignore events with a rational risk assessment similar, for instance, to the Design Standards then I'm OK with that .. however, the corporate assessment would consider the cost/benefit as an input into whether the existing organisation can/should do things such as missed approach terrain performance assessment ...
To keep the same procedure for all engines operating GAs as the EO procedure, would involve no thrust reduction nor acceleration until the first stop altitude.
That's a simple approach to life and, often, not the optimal way to address the problem .. no reason (where practical) why the AEO procedure can't be analysed to provide for keys throughout to shift to an OEI procedure .. a case of balancing complexity against flight standards commonsense as well ... what I would be suggesting is that the other extreme of just blasting off into the AEO procedure without anything prearranged in the case one goes quiet is pretty silly.
In my ops engineering work in another life, my approach to strategy was very much coloured by my parallel time in the cockpit ....
Is that a wise procedure to adopt in busy airspace when ALT busts would be more likely?
That's just one more constraint for the ops eng and flight standards assessment to factor into the final procedure.
I assume each of your destination airfields has a published EO proceedure for take off?
That should be the case only where necessary. Generally, I would expect to see
(a) some runways with the AEO miss being fine OEI
(b) some runways would have a generic escape procedure for simplicity
(c) where terrain etc., dictates, the remainder ought to have detailed OEI analyses in a manner similar to takeoff work.
in the event of a G/A following an EO approach, what is wrong with briefing and flying that profile rather than the published MAP?
Indeed, it would be a tad silly to do otherwise if such is promulgated .. ?