Abandoning a S/E Procedure
Joined: Jan 2002
Posts: 394
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From: USA
The original post that started the thread by LOKE talked to a S/E procedure for Oakland CA that turned the A/C back to the airport navaid to avoid the Bay Bridge. I'm thinking that a part of that procedure may be designed to avoid traffic from SFO, NAS Alameda, San Jose, NAS Moffit Field and goodness knows where else as well as terrain and very changable local wx.
A particular consideration in this case should be the communication with ATC. Presume this qualifies as an emergency, so the short radio call and executing the procedure that gets you out of the immediate danger and keeps fairly clear of other traffic seems to be the best course.
A particular consideration in this case should be the communication with ATC. Presume this qualifies as an emergency, so the short radio call and executing the procedure that gets you out of the immediate danger and keeps fairly clear of other traffic seems to be the best course.
Fleet Manager
Joined: Apr 2001
Aviation Qualifications: ATPL
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From: various places .....
The sensible ones which pay more than lip service to risk assessment and mitigation.
For procedures which generally accord with normal traffic patterns, SIDs, etc., there is probably no need to worry too much about ATC advice .. although .. those good folk might presume a much greater climb gradient AEO and factor that into traffic conflict planning .. and then along comes Bloggs OEI at, say, 3 percent or so ....
If there is likely to be a surprise factor for ATC, then it is pretty silly not to have them on the distribution list for the procedure. This might not cover all bases but goes some of the way.
For odd-ball procedures where the potential surprise factor is high, then I opt for the "give ATC a briefing on the procedure" in association with distribution. I have to say that I have never had any responses other than interested and appreciative from ATC offices for such an approach.
There is a resources (labour and cost) overhead involved, of course...
For procedures which generally accord with normal traffic patterns, SIDs, etc., there is probably no need to worry too much about ATC advice .. although .. those good folk might presume a much greater climb gradient AEO and factor that into traffic conflict planning .. and then along comes Bloggs OEI at, say, 3 percent or so ....
If there is likely to be a surprise factor for ATC, then it is pretty silly not to have them on the distribution list for the procedure. This might not cover all bases but goes some of the way.
For odd-ball procedures where the potential surprise factor is high, then I opt for the "give ATC a briefing on the procedure" in association with distribution. I have to say that I have never had any responses other than interested and appreciative from ATC offices for such an approach.
There is a resources (labour and cost) overhead involved, of course...
Joined: Sep 1999
Posts: 5,552
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From: ME
J_T, we have tried having that discussion with various ATC units, none of them wanted a procedure that wasn’t approved by their own authorities. We have spent over one year trying the get the Iranians to change the MAP gradient for a specific airport, they have redesigned it, flight tested it and for the last 6 months have waited for the signatures . Our OEI procedure for that airport doesn’t comply with their ICAO standards, there is no way that they are going to accept the procedure and there is no way that we can accept the SID departure. 
Mutt.
Mutt.
Joined: Jun 2004
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From: Australia
One of my primary tasks in performance engineering is the design of Specific Runway Procedures for OEI operations, call them escape routes if you will, they go by many names. A vitally important follow-up of this procedure design is the advice to pilots, through operational policy stated in the Operations Manuals, of how they are to be executed, and when circumstances may permit 'breaking off' as posed in the original post. And YES, for each one I have designed and implemented, I have personally visited the relevant ATC unit to advise of our requirements in the event of engine failure. They have been very receptive to this, I have not had to deal with the Iranians Mutt.
Before any discussion on appropriate circumstances to break off from an OEI procedure, it is appropriate to briefly detail the considerations that I make in creating a procedure.
(1) The procedure must be such that the maximum possible weight for takeoff may be obtained after considering all obstacles UNTIL SUCH TIME as the aircraft reaches an area where normal (PANS-OPS) obstacle clearance exists. This is usually the MSA.
(2) Even though 3rd segment altitude will almost always be below MSA, obstacle clearance must be assured AT the 3rd segment altitude for the remainder of the procedure, thus avoiding obstacle assessment during the 4th segment. This will require tracking procedures, normally directed to a holding pattern, where further climb to MSA may take place. (The holding pattern may not be a published one, but one created to meet FAR25 requirements for the continued climb). The published procedure MUST continue until MSA is achieved, the pilot does not have the facility to assess obstacles.
(3) The entire procedure will be contained within the MSA coverage, normally 25 nm, and within the control zone of the departure airport.
(4) All procedures must avoid areas of known high traffic density, such as secondary airports, VFR operations areas, and the approach and departure paths from the originating airport.
(5) Where a SID requires a turn BEFORE a turning point specified in the OEI Specific Procedure, a second RTOW is created for OEI compliance with the SID. If the Actual TOW exceeds this 'SID compliant' weight, ATC must be advised and the alternative procedure used.
These are the basics of the criteria that I use, in my opinion any performance engineer providing a lesser degree of protection IS SIMPLY NOT DOING THEIR JOB.
All engine failures do not occur at night and/or in IMC, and in the Operations Manual write-up, the following is specified as acceptable circumstances for the pilot to 'break-off' from a Specific Runway Procedure -
(1) The procedure may not be terminated under any circumstances before Acceleration Altitude is reached, the aircraft is in the en-route configuration, and thrust reduced to Maximum Continuous, and either
(2) In VMC conditions by DAY, normal obstacle clearance to comply with the VFR rules is assured, or
(3) At night or in IMC, the aircraft has achieved sufficient altitude and within the required tracking tolerances to comply with a published Holding or Instrument Approach procedure, or
(4) At night or in IMC, the aircraft is at such an altitude to comply with the ATC Radar Safe Altitude and is receiving Radar vectors.
A bit lengthy, I'm sorry, but I sleep easier at night knowing that the crews using my procedures have full obstacle assurance all of the way to where they can resume normal operations with PANS-OPS protection, and have a clearly defined flight path offering the best foreseeable traffic avoidance.
A final word to pilots using visual obstacle assessment, it's not usually the obvious big obstacles that are 'gonna getcha', it's the little subtle ones.
Old Smokey
Before any discussion on appropriate circumstances to break off from an OEI procedure, it is appropriate to briefly detail the considerations that I make in creating a procedure.
(1) The procedure must be such that the maximum possible weight for takeoff may be obtained after considering all obstacles UNTIL SUCH TIME as the aircraft reaches an area where normal (PANS-OPS) obstacle clearance exists. This is usually the MSA.
(2) Even though 3rd segment altitude will almost always be below MSA, obstacle clearance must be assured AT the 3rd segment altitude for the remainder of the procedure, thus avoiding obstacle assessment during the 4th segment. This will require tracking procedures, normally directed to a holding pattern, where further climb to MSA may take place. (The holding pattern may not be a published one, but one created to meet FAR25 requirements for the continued climb). The published procedure MUST continue until MSA is achieved, the pilot does not have the facility to assess obstacles.
(3) The entire procedure will be contained within the MSA coverage, normally 25 nm, and within the control zone of the departure airport.
(4) All procedures must avoid areas of known high traffic density, such as secondary airports, VFR operations areas, and the approach and departure paths from the originating airport.
(5) Where a SID requires a turn BEFORE a turning point specified in the OEI Specific Procedure, a second RTOW is created for OEI compliance with the SID. If the Actual TOW exceeds this 'SID compliant' weight, ATC must be advised and the alternative procedure used.
These are the basics of the criteria that I use, in my opinion any performance engineer providing a lesser degree of protection IS SIMPLY NOT DOING THEIR JOB.
All engine failures do not occur at night and/or in IMC, and in the Operations Manual write-up, the following is specified as acceptable circumstances for the pilot to 'break-off' from a Specific Runway Procedure -
(1) The procedure may not be terminated under any circumstances before Acceleration Altitude is reached, the aircraft is in the en-route configuration, and thrust reduced to Maximum Continuous, and either
(2) In VMC conditions by DAY, normal obstacle clearance to comply with the VFR rules is assured, or
(3) At night or in IMC, the aircraft has achieved sufficient altitude and within the required tracking tolerances to comply with a published Holding or Instrument Approach procedure, or
(4) At night or in IMC, the aircraft is at such an altitude to comply with the ATC Radar Safe Altitude and is receiving Radar vectors.
A bit lengthy, I'm sorry, but I sleep easier at night knowing that the crews using my procedures have full obstacle assurance all of the way to where they can resume normal operations with PANS-OPS protection, and have a clearly defined flight path offering the best foreseeable traffic avoidance.
A final word to pilots using visual obstacle assessment, it's not usually the obvious big obstacles that are 'gonna getcha', it's the little subtle ones.
Old Smokey
Joined: May 2003
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From: The Roman Empire
One of the funniest escape routes I've seen was for RWY35L in LIMC: instead of turning left as per Sid, it called for a RIGHT turn crossing the missed approach of 35R!
In the name of a higher payload.
In the name of a higher payload.
Joined: Jun 2001
Posts: 3,991
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From: UK
Emergency Turns are so called because that's what you are going to do in event of an engine failure (which I would call an emergency!) in order to ensure compliance with performance requirements.
They are usually promulgated by the company when the straight climb out would make the RTOW too limiting.
In all the companies (UK) that I have flown for all our emergency turn procedures at specific airports were pre notified to ATC by the Nav Dept. Whether a specific controller on the day is aware of the company emergency turn is another matter!
They are usually promulgated by the company when the straight climb out would make the RTOW too limiting.
In all the companies (UK) that I have flown for all our emergency turn procedures at specific airports were pre notified to ATC by the Nav Dept. Whether a specific controller on the day is aware of the company emergency turn is another matter!
Joined: Mar 2002
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From: Euroland
I would like to pick up on the points made by Nigel and LEM stating that they sit down and plan in advance to ignore the OEI procedure and simply fly the aircraft out to sea because they considder flying to a point over land to be a silly idea in the circumstances.
Could it be that the person who approved the procedure in the ops manual (Chief Pilot?) believes that when a twin has an engine failure and becomes a single engine aircraft, taking a public transport flight in a (now) single engine aircraft well out to sea would not be ideal if the aircraft could acheive obstacle clearance over land?
Just a thought.
Regards,
DFC
PS - What's the rush to ditch the procedure? Isn't the idea that in an emergency we don't rush things unnecessarily?
Could it be that the person who approved the procedure in the ops manual (Chief Pilot?) believes that when a twin has an engine failure and becomes a single engine aircraft, taking a public transport flight in a (now) single engine aircraft well out to sea would not be ideal if the aircraft could acheive obstacle clearance over land?
Just a thought.
Regards,
DFC
PS - What's the rush to ditch the procedure? Isn't the idea that in an emergency we don't rush things unnecessarily?
Joined: Jun 1999
Posts: 408
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From: Queensland
LEM, circumstances like you describe are not too uncommon. It is unlikely that all operators to such an airport would brief ATC on their s/e procedure. One day there will be a mid-air & the !!!! will hit the fan world-wide, as airlines & ATC try to profess their ignorance of the risk and blame it on the crews. Its not so serious at a purely domestic airport with just a couple of good airline operators. Make it international with lots of airlines, throw in a few african freighters, fatigue, weather, english as a 3rd language, cultural difficulties etc and the risk is higher. There are a lot of controllers, pilots and aviation authorities with their heads in the sand.
PPRuNeaholic
Joined: Jun 2000
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From: Cairns FNQ
I'd like to add my "tuppence worth" to the post by DFC. Heading out over water, while it is a very tempting idea, would require the pilot to assess the risk associated with the existence of a super tanker, aircraft carrier, or any similarly tall vessel, crossing the extended centreline of the runway at the critical moment.
How high will the aircraft be at that point?
How tall is the ship?
Where, exactly, is the first point where the risk exists?
And then, of course, is there any possibility of the existence of an amphibious aircraft operation at the critical time?
Of course, as DFC suggests, even without such a problem, how high is the aircraft going to be in the first couple of miles? How much time will there be to go thru a ditching drill and get the pax ready for that?
These might be some of the reasons why an emergency procedure avoids going over water for anything but the shortest possible time.
As for the reference made by autoflight that "There are a lot of controllers, pilots and aviation authorities with their heads in the sand." I think it needs to be said that there is no clear way for ATC or regulators to predict the climb performance of any particular aeroplane in any given emergency situation. If pilots actually want these emergency procedures to be standardised, it will undoubtedly have to be taken up with ICAO (for Pans Ops) and the FAA (for TERPS).
And, even if you can get those two to actually agree on a standard forumula, it is likely to cater for the worst case scenario only. And that will undoubtedly result in a heavily reduced payload for most aircraft. This whole argument can go around and round and I can't say that I have any suggestions on ways to improve the situation - I'm sure that I'd be a millionaire if I could do that.
How high will the aircraft be at that point?
How tall is the ship?
Where, exactly, is the first point where the risk exists?
And then, of course, is there any possibility of the existence of an amphibious aircraft operation at the critical time?
Of course, as DFC suggests, even without such a problem, how high is the aircraft going to be in the first couple of miles? How much time will there be to go thru a ditching drill and get the pax ready for that?
These might be some of the reasons why an emergency procedure avoids going over water for anything but the shortest possible time.
As for the reference made by autoflight that "There are a lot of controllers, pilots and aviation authorities with their heads in the sand." I think it needs to be said that there is no clear way for ATC or regulators to predict the climb performance of any particular aeroplane in any given emergency situation. If pilots actually want these emergency procedures to be standardised, it will undoubtedly have to be taken up with ICAO (for Pans Ops) and the FAA (for TERPS).
And, even if you can get those two to actually agree on a standard forumula, it is likely to cater for the worst case scenario only. And that will undoubtedly result in a heavily reduced payload for most aircraft. This whole argument can go around and round and I can't say that I have any suggestions on ways to improve the situation - I'm sure that I'd be a millionaire if I could do that.
Joined: Jun 1999
Posts: 408
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From: Queensland
Plan A: There will be many runways where the escape route is obvious and can be selected as standard. Operators wishing to substantially comply with the standards set for each such runway will not be unduly penalised by following them if required. The airways clearance would automatically include a contingency for the standard s/e procedure. Operators will normally go for the standard, rather than have their flights delayed by a special contingency clearance .
PLAN B: If an operator wants to squeeze in the last kilogram of payload / fuel on a regular basis, and devises a s/e procedure that is better able to do this, it could be annotated on the flight plan. If this case, the departure clearance will include a provision for that.
For runways where the escape route is not so obvious and operators choose different s/e routes, see Plan B.
PLAN B: If an operator wants to squeeze in the last kilogram of payload / fuel on a regular basis, and devises a s/e procedure that is better able to do this, it could be annotated on the flight plan. If this case, the departure clearance will include a provision for that.
For runways where the escape route is not so obvious and operators choose different s/e routes, see Plan B.
Joined: Dec 2003
Posts: 2,349
Likes: 845
From: Tring, UK
Good discussion.
Something that occasionally passes through my mind is the S/E G/A. You have taken off, had your engine failure, followed the ET, climbed to MSA, etc. then returned to the airfield, unfortunately becoming unable to land at the last minute (maybe using a different runway to the one you took off on).
I understand (and I stand to be corrected) that most performance calculations only give obstacle clearance out to 1,500' AAL, clean and after that you are on your own. Given that SID profiles are normally quite different to missed aproaches, should consideration be given to flying a departure instead of a G/A?
If you end up landing (or attempting to land) on another runway, you may be unable to make the gradient required on the appropriate SID but also be 'in the poo' if following the standard G/A...
Maybe the answer is something close to a missed 'circling' approach, involving manoevring to get on an appropriate departure, although terrain at some airfields may negate this.
Anyone got any particular thoughts?
Something that occasionally passes through my mind is the S/E G/A. You have taken off, had your engine failure, followed the ET, climbed to MSA, etc. then returned to the airfield, unfortunately becoming unable to land at the last minute (maybe using a different runway to the one you took off on).
I understand (and I stand to be corrected) that most performance calculations only give obstacle clearance out to 1,500' AAL, clean and after that you are on your own. Given that SID profiles are normally quite different to missed aproaches, should consideration be given to flying a departure instead of a G/A?
If you end up landing (or attempting to land) on another runway, you may be unable to make the gradient required on the appropriate SID but also be 'in the poo' if following the standard G/A...
Maybe the answer is something close to a missed 'circling' approach, involving manoevring to get on an appropriate departure, although terrain at some airfields may negate this.
Anyone got any particular thoughts?
Joined: Jun 1999
Posts: 408
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From: Queensland
I always briefed for terrain clearance following GA. If required, minimum clean speed & T/O power to the time limit. I agree that not enough consideration is given to the gap between 1500ft and safe altitude. If the authorities and the airlines don't do it, it is up to each captain to do so.
Joined: Jun 2004
Posts: 1,843
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From: Australia
It is a good discussion.
I find it very disturbing to read here and there of pilots who want to 'reinvent' the OEI procedures, break off and head out to sea, or attempt to follow the SID. How well did the proponents of such ideas survey the new field of obstacles in doing so ?
Obstacles are assessed very accurately for OEI Special Procedures, and the optimum path chosen. They have to be, margins of obstacle clearance to comply with FAR25 (or it's equivalent) are EXTREMELY small, and small obstacles that wouldn't cause a moment of consideration for crews familiar with a particular airport during normal operations can become critical.
Consider a 100 foot radio mast at 1 nautical mile from the departure end of a 3000 M runway. At the line-up point, can you accurately assess this mast at a distance of 4.8 Km, a mere 1/3 of a degree above the horizontal to the pilot's eye position ? Well, it's a critical obstacle for a 2 engined aircraft at performance limiting weights. So too is a 6 foot man at 1000 feet from the runway end. Now put these same 'indiscernable' obstacles in the 'reinvented' OEI route for those who want to take another route and see the outcome. As I said in an earlier post -"it's not usually the obvious big obstacles that are 'gonna getcha', it's the little subtle ones".
I see cynical remarks in these posts regarding procedures to squeeze the last possible Kilo of payload. Do these same cynics realise that if the performance engineer has chosen a route that obtains those last few kilos of payload, that this must imply that that is the path with the LEAST obstacles, and is therefore the SAFEST. This is one of those rare cases where if you choose the SAFEST option in terms of terrain clearance, then it is also the most commercially viable. A rare marriage.
DFC, you made the statement -"Could it be that the person who approved the procedure in the ops manual (Chief Pilot?)...etc", The procedures are created by performance engineers poring over incredibly large scale survey charts, municipal maps, etc...stuff that is not available amongst normal aeronautical charts etc. These fall far far short of adequacy to evaluate safe routes for OEI procedures. It is a full time job for P/Es and their staff.
It is acknowledged that there are some lousy procedures "out there", but properly designed procedures get you all the way up to MSA, and DO consider high density traffic areas etc., including the shipping alluded to by OzExpat. Do the OEI reinventers consult the shipping authorities to ascertain the largest vessels able to use over-water areas envisaged ? I do. Again, the 'lousy' procedures stick you with one single procedure, often incompatible with the SID. A good service provider will supply OEI data to comply with the SID (usually much more restrictive), in addition to the optimum data over an optimised route, which, if required for your actual Takeoff Weight, must be advised to ATC.
OEI procedures are created by, and provided by the operator (or the operator's sub-contractor). There is a good case to canvass, at ICAO level, for standard, optimised, OEI escape routes for all runways. Until that time, it is an issue that pilots must take up with their management, or their performance engineering departments.
Until that time, for God's sake, for your sake, for your passenger's sake, follow the OEI published procedure.
Please.....I might be one of your passengers.
Old Smokey
I find it very disturbing to read here and there of pilots who want to 'reinvent' the OEI procedures, break off and head out to sea, or attempt to follow the SID. How well did the proponents of such ideas survey the new field of obstacles in doing so ?
Obstacles are assessed very accurately for OEI Special Procedures, and the optimum path chosen. They have to be, margins of obstacle clearance to comply with FAR25 (or it's equivalent) are EXTREMELY small, and small obstacles that wouldn't cause a moment of consideration for crews familiar with a particular airport during normal operations can become critical.
Consider a 100 foot radio mast at 1 nautical mile from the departure end of a 3000 M runway. At the line-up point, can you accurately assess this mast at a distance of 4.8 Km, a mere 1/3 of a degree above the horizontal to the pilot's eye position ? Well, it's a critical obstacle for a 2 engined aircraft at performance limiting weights. So too is a 6 foot man at 1000 feet from the runway end. Now put these same 'indiscernable' obstacles in the 'reinvented' OEI route for those who want to take another route and see the outcome. As I said in an earlier post -"it's not usually the obvious big obstacles that are 'gonna getcha', it's the little subtle ones".
I see cynical remarks in these posts regarding procedures to squeeze the last possible Kilo of payload. Do these same cynics realise that if the performance engineer has chosen a route that obtains those last few kilos of payload, that this must imply that that is the path with the LEAST obstacles, and is therefore the SAFEST. This is one of those rare cases where if you choose the SAFEST option in terms of terrain clearance, then it is also the most commercially viable. A rare marriage.
DFC, you made the statement -"Could it be that the person who approved the procedure in the ops manual (Chief Pilot?)...etc", The procedures are created by performance engineers poring over incredibly large scale survey charts, municipal maps, etc...stuff that is not available amongst normal aeronautical charts etc. These fall far far short of adequacy to evaluate safe routes for OEI procedures. It is a full time job for P/Es and their staff.
It is acknowledged that there are some lousy procedures "out there", but properly designed procedures get you all the way up to MSA, and DO consider high density traffic areas etc., including the shipping alluded to by OzExpat. Do the OEI reinventers consult the shipping authorities to ascertain the largest vessels able to use over-water areas envisaged ? I do. Again, the 'lousy' procedures stick you with one single procedure, often incompatible with the SID. A good service provider will supply OEI data to comply with the SID (usually much more restrictive), in addition to the optimum data over an optimised route, which, if required for your actual Takeoff Weight, must be advised to ATC.
OEI procedures are created by, and provided by the operator (or the operator's sub-contractor). There is a good case to canvass, at ICAO level, for standard, optimised, OEI escape routes for all runways. Until that time, it is an issue that pilots must take up with their management, or their performance engineering departments.
Until that time, for God's sake, for your sake, for your passenger's sake, follow the OEI published procedure.
Please.....I might be one of your passengers.
Old Smokey
Joined: Sep 1999
Posts: 5,552
Likes: 25
From: ME
I never cease to be amazed at the number of crew who believe that they are protected for obstacles when they fly a SID with an engine out.
Not always true, we have particular airports where we know the required takeoff weight, its not achievable on any of the SID tracks. Therefore the OEI is unique.
I would love to say that this is always true
I would love to see ICAO level, for standard, optimised, OEI escape routes for all runways. It would make life so much easier and safer.
Mutt.
A good service provider will supply OEI data to comply with the SID (usually much more restrictive)
The procedures are created by performance engineers poring over incredibly large scale survey charts, municipal maps, etc...stuff that is not available amongst normal aeronautical charts etc.
I would love to see ICAO level, for standard, optimised, OEI escape routes for all runways. It would make life so much easier and safer.
Mutt.
Joined: Jun 2004
Posts: 1,843
Likes: 0
From: Australia
Mutt,
My quote - "A good service provider will supply OEI data to comply with the SID (usually much more restrictive)"
Your quote - "Not always true, we have particular airports where we know the required takeoff weight, its not achievable on any of the SID tracks."
To qualify this, SECONDARY data is made available for those SIDs which can accomodate 'reasonable' weights. Certainly not all of them. PRIMARY data is always available via the OEI route, invariably different to the SID.
Regards,
Smokey
My quote - "A good service provider will supply OEI data to comply with the SID (usually much more restrictive)"
Your quote - "Not always true, we have particular airports where we know the required takeoff weight, its not achievable on any of the SID tracks."
To qualify this, SECONDARY data is made available for those SIDs which can accomodate 'reasonable' weights. Certainly not all of them. PRIMARY data is always available via the OEI route, invariably different to the SID.
Regards,
Smokey
Fleet Manager
Joined: Apr 2001
Aviation Qualifications: ATPL
Posts: 7,448
Likes: 310
From: various places .....
Re obstacles and obstacle profiles .. it depends ...
(a) if an obstacle clear gradient is declared by inclino survey, then that's fine ... you just lose some payload (usually) but it is quick and dirty to calculate and fly the straight flight path.
(b) pity that some in (a) are done by working back from the topo or Type A .. defeats any cost and utility value of inclino surveys.
(c) Type A is fine .. but, for a jet twin, especially with a big V2 to fourth segment climb speed split ... usually doesn't go anywhere near far enough .. does 40-50 nm takeoff path cause any concern in some cases ... ?
(d) generally, the ops engineers are on their own .. on quite a few occasions, either we throw a theodolite over the shoulder to go and do some rough field work, and/or commission a surveyor to do the work for critical obstacles if they are sufficiently critical ...
(e) lots of useful data around but, at the end of the day .. muddy boots and a 4WD sort out a lot of critical problems ..
Fortunately, for most departures, the topo etc., data can be used to identify critical bits outside/beyond the Type A or equivalent. One needs to keep in mind that, in the event of an early turn taking the aircraft out of the Type A splay ... the ops engineer is back to basics.
And, at the expense of repeating what my colleagues keep saying .. the guy in the sharp end can't estimate the delta between climb needed and climb available .... a bit late in the last 20-30 seconds to realise that that is the case ...
(a) if an obstacle clear gradient is declared by inclino survey, then that's fine ... you just lose some payload (usually) but it is quick and dirty to calculate and fly the straight flight path.
(b) pity that some in (a) are done by working back from the topo or Type A .. defeats any cost and utility value of inclino surveys.
(c) Type A is fine .. but, for a jet twin, especially with a big V2 to fourth segment climb speed split ... usually doesn't go anywhere near far enough .. does 40-50 nm takeoff path cause any concern in some cases ... ?
(d) generally, the ops engineers are on their own .. on quite a few occasions, either we throw a theodolite over the shoulder to go and do some rough field work, and/or commission a surveyor to do the work for critical obstacles if they are sufficiently critical ...
(e) lots of useful data around but, at the end of the day .. muddy boots and a 4WD sort out a lot of critical problems ..
Fortunately, for most departures, the topo etc., data can be used to identify critical bits outside/beyond the Type A or equivalent. One needs to keep in mind that, in the event of an early turn taking the aircraft out of the Type A splay ... the ops engineer is back to basics.
And, at the expense of repeating what my colleagues keep saying .. the guy in the sharp end can't estimate the delta between climb needed and climb available .... a bit late in the last 20-30 seconds to realise that that is the case ...