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EOSID -v- EFP any comments on differences?

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EOSID -v- EFP any comments on differences?

Old 20th Oct 2010, 16:10
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EOSID -v- EFP any comments on differences?

All.

Looking for help/comments/thoughts from your operators and your experience.
Being relatively new to all things performance, I am curious about EOSID's.
My company use EFP (engine fail procedures) that follow all the requirements of EU-Ops and are integral to our RTOW charts. Our EFP's are supplied by a 3rd party (who also supply our obstacle data and take-off chart software) and are quality checked manually by ourselves internally.
I have now heard, read about EOSID and wonder if this is the same name for what we call EFP? From all I have read the criteria seems the same (ref CAAP 235-4(0)) and our EFPs also cover engine fail after the point where the EFP and SID seperate.

We are also considering other suppliers for aircraft charts and I have noted though that some of these products contain EOSID pages along with SID/STAR etc. I have (remmeber I am new) always considered the data/information in the charts 'generic' (derived from state/AIP) and each supplier just has different formats/quality of presenting it. It therefore seemed odd to me that they contained EOSID procedures, which if they are the same as our EFP's, are particular to our aircraft performance and also, to a degree, our SOP's and preferences and therefore NOT generic at all. Of course some EFP's (EOSID's???) will be quite simple at airfields that present no real challenge on climb gradient, terrain/obstacles etc. but many will.

Can I ask for any comments/guidance on if there is a difference and if any operators buy such a thing as 'generic' EOSID procedures?

ORJ
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Old 21st Oct 2010, 10:01
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From what I know you`re supposed to follow the first part of the SID.In case that the aircraft capabilities cannot meet the requirements(gradients),than the airport,togheter with the publisher of the charts develop an escape route named the Engine Out procedure.In Jeppesen Manuals,it`s the chart nr 10-7 for every airport.At least this is the SOP in our Company.If you don`t have a 10_7 you`ll just follow the first part of the SID until clear of obstacles then decide the course of action.
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Old 21st Oct 2010, 11:37
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AlexMambo.

thank you very much for your post and being the 1st to respond to this thread. It is really appreciated.

That said, what you have written does not sound right to me. To my knowledge simply following a SID will not ensure you clear obstacles / terrain with one engine out - you might, but you may not also. I thoght the purpose of SID was to simplify departure procedures for crew/ATC alike by giving a std route from the airfield to an airway/routing - although it takes account of MSA it does not (to my knowledge) take account of aircraft performance with 1 engine inop...and even if it did, what aircraft - a 737, 757, A321?

Taking the part of the EOSID, (chart No 10-7 in Jepp manuals, you advise: sorry I don't have those so taking your word) you say these are designed by airport and chart producers (jepp) - my questions is then, how do either of these know 'your' aircraft performance capabilities from your AFM and how do these charts relate to the weight in your RTOW tables/calculations? All our tables give an RTOW that (balanced with variables for temp/altitiude/QNH tec.) consider our climb gradient capability with one engine inop -v- the specifics of the airfield.

Hopefully we can get some more responses and make this an indepth and valuable debate.

Thanks again
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Old 21st Oct 2010, 12:02
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Hi Ops_Room_Junkie,

I think perhaps the previous poster was referring to Airports like Geneva, who publish initial minimum climb gradients, and actions if minimum Altitudes are not met.

All our performance tables (now on board performance computers) had been in house approval of other agencies' calculations.
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Old 21st Oct 2010, 12:06
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RR: okay, thanks for that thought.
Just a question, do you have 1 engine out procedures as part of your EFB?
If so what are they reffered to? Trying to understand if our EFP's equate to EOSID's?

thanks ORJ
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Old 21st Oct 2010, 12:25
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Hi ORJ,

It's referred to as "Emergency Procedure" and may be as simple as climb straight ahead to 1500 ft then turn to a specified holding beacon, or more complex with an early turn and no acceleration until established on a track, or above an altitude etc. They all finish at a safe holding facility.

The TOGA Performance Limited mass is calculated, and an appropriate flex temperature (when actual mass entered) is given.
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Old 21st Oct 2010, 12:44
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Hello,

I worked for several companies and in one company the name for "engine failure procedure" was EOSID (Engine Out SID) in another it was simple EFP (Engine failure procedure) another called it EOP (Engine Out Procedure)... but it's all the same.
I think Jeppesen called it EFP while Lido called it EOSID.
Since on our airplane with an engine out we'll never meet the required gradient we always have an engine failure procedure and if there is nothing specified it's simple straight ahead.

The most important is that the operator is responsible to establish such procedures when you are not able to meet the climb gradients of a normal SID in case of an engine failure. So ATC doesn't know your engine out procedure! For this reason it's very important to report the procedure to ATC!
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Old 21st Oct 2010, 13:43
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B738.

Many thanks - your response (hopefully) confirms what I thought, that EFP, EOP, Emergency Turn, EOSID are all differing names for the same process: that which gives you clear direction on where to head if you suffer an engine loss after V1 that will safely clear obstacles and terrain. This as an inergral part of RTOW calculations ensures you are at a weight that will ensure your climb gradient is sufficient.

ORJ
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Old 21st Oct 2010, 20:50
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It goes by many names, they're all the same thing. As the OP, Ops_Room_Junkie said "Emergency Turn, EOSID are all differing names for the same process", add to that SRP (Specific Runway Procedure).

Ops_Room_Junkie brought up an important question in the original post (thus far un-answered) that being "..... such a thing as 'generic' EOSID procedures?"

Absolutely NOT, it may be possible in simpler OEISIDs such as an over-water Takeoff, but throw in the normal scattering of obstacles at the normal scattering of distances, and the generic procedure is going to turn to junk.

There are three (3) factors which make SPECIFIC OEISIDs necessary / desirable, to wit -

(1) Operating Speed of the Aircraft,
(2) Time limit for Takeoff Thrust for the Aircraft, and
(3) The number of engines for the aircraft.

Operating Speed of the Aircraft - Even for aircraft in the same category, there's a wide range of operating speeds, for example an A319 has a very much lower V2 and final Clean (4th segment) speed than for another 2 engined aircraft such as the B777-300ER. Different speeds means different turn radii, upon which the flight path and the splay required to avoid obstacles laterally will differ greatly. For each aircraft the Maximum and the Minimum possible V2 (for example) will be used to compute the outer and the inner limits of the splay. For the example, let's say that the smaller aircraft has a V2 max of 140 Kt, and the larger has a 190 Kt max V2. The outer limits of a turn (with it's splay) based upon 140 Kt may completely avoid a significant obstacle, and is of no concern. At the higher 190 Kt V2 with it's attendant MUCH higher turn radius, the critical obstacle is now 'slap bang' in the area covered by the splay, and a steeper 2nd segment climb is required. Do you want to impose this penalty on the slower aircraft? I think not, it's not required, and would incur a significant unnecessary payload on the aircraft if we used generic OEISIDs.

One solution to this problem if we're creating generic OEISIDs might be to bring back the turning point closer to the airport, both aircraft are now happy with that 'outer' obstacle, but what of the INNER splay? The inner splay is based upon the minimum V2 for the aircraft, the 'slow' aircraft with it's smaller turn radius may now encounter new, previously unconsidered critical obstacles on the inner side of the splay, which need not be considered for the faster aircraft with it's larger turn radius at it's minimum V2. Both aircraft are penalised by the use of the 'revised' generic OEISID

So far - Thumbs down #1 to generic OEISIDs. (J_T, I was thinking of Hobart 30 as I wrote this).

.2. Time limit for Takeoff Thrust for the Aircraft - Typically we operate to a 5 minute or 10 minute limit to Takeoff thrust. As a generalised approximate, I've found that a 3rd Segment altitude of 1300 ft is OK for the 5 minute limited aircraft. So what happens if the obstacles require a 1700 ft 3rd Segment altitude? For the 10 minute limited aircraft, no problem, keep on truckin' straight ahead, but for the 5 minute aircraft, a turn will be required generating a whole new OEISID before the critical (further out) obstacles are encountered. This turn is not required for the '10 minute' aircraft, but if we're producing generic procedures, now the '10 minute' aircraft is going to suffer.

So far - Thumbs down #2 to generic OEISIDs. (J_T, I was thinking of Albury 07 as I wrote this).

(3) The number of engines for the aircraft - The 2, 3, and 4 engined aircraft require to achieve a minimum Net 2nd Segment gradient of 1.6%, 1.8%, and 2.0% respectively. Now let's put an obstacle in the 2nd segment requiring a gradient of 1.9%. No problem for the 4 engined aircraft, it's not a critical obstacle - keep on truckin'. For the 2 and 3 engined aircraft one option is to continue straight-ahead accepting the now critical obstacle, but suffering a payload restriction due to the increased climb gradient required, an obstacle climb limit. The 2 and 3 engined aircraft suffer. A solution is to build a OEISID for them with a turn before the critical obstacle, and over 'non-critical' terrain. So now the 4 engined aircraft, if we built generic procedures, is stuck with an unnecessary emergency turn. (For shortening, 1st segment gradient differences haven't been considered at all, but they're lurking out there).

So far - Thumbs down #3 to generic OEISIDs. (J_T, I was thinking of Tulla 34 as I wrote this).

Generic OEISIDs, of necessity, try to be, and have to be, all things to all people. The old truism of "You can't please all of the people all of the time" was never so relevant. The problem is that inevitably, someone is going to suffer. Having said that, creation of generic OEISIDs with everyone suffering performance penaltys, is better than no OEISIDs at all.

Even more so, having a generic OEISID available, warts and all, is infinitely preferrable to flight with those MORONIC BLOODY IDIOTS who would follow the normal SID following engine failure. That's another subject.

There's a lot more to it than the major points expressed here, but please, please don't ever use OEISIDs developed for another aircraft type for your own operations..... please!

Regards,

Old Smokey
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Old 21st Oct 2010, 21:38
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Simples

EFP applies to the Net Take-off Flight Path which ends at 1500' agl. It is usually employed to manoeuvre around an obstacle within the Net Take-off Flight Path that would otherwise limit the mass at which you can take off. Having an EFP (sometimes known as an Emergency Turn) allows the performance limited take-off mass to be increased. EFP's are promulgated by (or on behalf of) the aircraft operator.

If it is expected that obstacle clearance throughout the whole of the SID will not be maintained in the event of an engine failure, the Airport Authority may publish an alternative SID that will ensure obstacle clearance is maintained.
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Old 21st Oct 2010, 21:53
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The inner splay is based upon the minimum V2 for the aircraft

there is one extra item in the ops engineering bag of tricks which can help out here - if the outer splay then doesn't create problems with rocky bits, one can restrict the normal (max) 15° bank OEI turn by specifying a lesser bank. This, for the min V2, opens up the turn radius. Obviously, one doesn't add to the pilot's woes at the time by specifying an unflyable intermediate angle like 12.5° ... but 5° and 10° are worth looking at, where relevant. As in everything ops engineering, life is a succession of compromises.

don't ever use OEISIDs developed for another aircraft type for your own operations

.. and we've all seen this sort of thing done.

I recall just this happening in a Regulator's navaid flight checking organisation (which ought to have known better) where the said organisation pinched some jet OEI escape procedures from another operator (one near and dear to OS's historical heart) and applied them to a much smaller (and VERY much slower) turboprop Type.

Our good colleague, Centaurus, has a range of tales along these lines to relate from a variety of operators (pilots for the flying for) over the years.

If it is expected that obstacle clearance throughout the whole of the SID will not be maintained in the event of an engine failure, the Airport Authority may publish an alternative SID that will ensure obstacle clearance is maintained.

.. and, if you REALLY believe that, I have a bridge to sell you. Had you suggested something like an alternative SID that may improve obstacle clearance I would have concurred.

SIDs, at best, have only a tenuous connection to obstacle clearance in the real world.

One might refer back to OS's wise words ..
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Old 22nd Oct 2010, 09:04
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Perhaps I knew more than I thought...???

JT/OS - thank you so much for your responses which show clearly you have a depth of knowledge and grasp on this subject matter far beyond what I can even aspire to at present. I sincerley appreciate your time to share your experience on this subject.

It is also good to finally have two matters cleared for me: 1/ EFP/EOSID etc - same subject, different names (is this done to confuse the newer people to this game, like flap settings for Boeing -v- Airbus!). 2/ that GENERIC EOSIDs are only for the foolhardy and cannot (apart from the most simple airfields) guarantee you can be sure you ain't gonna hit anything with OEI.

My final thought from reading the postings, is that perhaps I knew a little more than I thought. Still a long way to go (and there always will be - whcih is why I love 'performance' so much!) but reading the lack of appreciation for what has to be considered for a fully evalued EFP/EOSID and thinking that the basic obstacle/terrain avoidance in a state/airport issued generic SID will see you okay, is quite alarming.

I just hope a few more can read and join this debate as clearly there is much to be said and learnt from every subject.
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Old 22nd Oct 2010, 09:49
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ORJ: You seem to have a good understanding of the topic. I am somewhat involved with implementation and training of our EFB Performance Software and little more understanding of Performance Class A came as a necessity.

My advice would be to carefully listen to all what OS and j_t share with us and proceed with great caution and utmost suspicion if anybody tells you things differently. Next best thing is to look up their posts from the forum archive.
For some self-study, look up Airbus publication Getting to Grips with Aircraft Performance; as far as I know it had not been updated recently so make sure the quoted regulations apply to your operational environment.

I am very far from being a performance engineer of any sort, but here are some of the key points I discovered. At the same time, I am not convinced these are understood well among day-to-day line pilot community.
  • a) Why generic FCOM RTOW charts with no embedded obstacle data are close to useless,
  • b) Why RTOW charts with obstacle data but no description of lateral track are close to useless
  • c) Why deviating from the OEI prescribed lateral track puts you in peril; that includes cleaning up before starting a turn where the turn is prescribed upon reaching EO ACC ALT
  • d) Why EFPs that do not end in a holding fix fail to address some fundamental issues
  • e) Why MEA/MORA between ADEP and TKOF ALTN needs to be evaluated as well
  • f) Why Eng Failure at top of the V1 range is not the most limiting ASDA scenario
  • g) Why using wet performance figures instead of dry reduces your performance margins and, if the runway is damp, is illegal
  • h) Why AST/FLEX takeoff is inherently safer
  • i) Why AST/FLEX takeoff stop margin displayed as a result of most calculations has very little relevance to actual achieved ASD
  • j) Why fixed derate may provide more payload while AST/FLEX does not
  • k) Why using full thrust in OEI could be deadly if you had calculated fixed derate
  • l) Why, in weird cases, intersection departures may yield better payload / higher AST/FLEX
  • m) Why rolling take-offs are mostly ok
  • n) Why line-up distance allowance is not a laughing matter
  • o) Why the amount AIP provided obstacle data is grossly insufficient for proper TKOF performance calculations in places where terrain is a factor.
You see, I am still only half way down the alphabet

Sorry for such a large thread drift, but I think your original question had been successfully explained.

Sincerely,
FD (the un-real)

Last edited by FlightDetent; 22nd Oct 2010 at 10:02. Reason: poor spell checking
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Old 22nd Oct 2010, 10:51
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FD - thanks for the additions to the thread and I think it just shows how much there is to consider. I have a good understanding of much what you list and a working knowledge of the rest, I am still at the phase where I don't know it 'off the cuff' but know of it and where to research it/calculate it: to be honest, I like it that way in some respects - I will therefore never assume I know it without checking.

I was recently in a room full of industry bod's and it was amazing just how many did not get AST/FLEX and how it is safer (they felt it was less safe and would rather 'give it a bit more') - also agree that stop margin when using AST has little to do with real ASD, but it sits on the safe side so all is well in the world.

Clearly enough to keep me interested for all my working days!
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Old 22nd Oct 2010, 10:54
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Why, in weird cases, intersection departures may yield better payload / higher AST/FLEX

Can't recall seeing this one in my work before. Can you walk us through an example ?
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Old 22nd Oct 2010, 13:02
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All other factors being equal (i.e. obstacle free path), the intersection's different slope and elevation at TORA start seem to play a role. I just managed to run some calculations and could replicate the situation for A321 with 33k engines at 72t obtaining higher FLEX from RWY 06 E here http://lis.rlp.cz/ais_data/aip/data/valid/a2-pr-adc.pdf.

Upon closer scrutiny, you did caught me red handed (why is that no surprise ) and my statement under L above in weird cases, intersection departures may yield better payload / higher AST/FLEX is incorrect.

Max payload is reduced for intersection (2.5t).
For the low given weight AST/FLEX figure is 1 deg greater at the intersection. I suppose this is only valid as long as AST/FLEX is at max -25% and the thrust setting is affected by nothing else than density elevation. I am not qualified to speculate what impact the different input AST/FLEX have on FADEC commanded N1 or resulting EGT.

A321-211 0 kt 13C 1020 hPa CF:2 A/C: Off EAI: Off

LKPR 06 DRY ELEV 1202 SLP -0,4 deg RWY 3715 CWY 300 STPW 0 OBST 0 LineUp 90 deg
PLW 98324 kg Max Structural 89000
at 72000 kg Flex 55 V1 122-145 VR 145 V2 147 ACC ALT 2707

LKPR 06 E DRY ELEV 1191 SLP -0,0 deg RWY 3060 CWY 300 STPW 0 OBST 0 LineUp 90 deg
PLW 95877 kg Max Structural 89000
at 72000 kg Flex 56 V1 138-149 VR 150 V2 150 ACC ALT 2691


I sincerely wish the audience would save time spent over this negligible niche in favor of reading some of yours/OSs work on Vmca and wet considerations.

Yours,
FD (the un-real
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Old 24th Oct 2010, 11:28
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the intersection's different slope and elevation

Now, had I thought about it .. I would have realised that - good point. The delta elevation probably will be fairly inconsequential but the delta slope might give a noticeable change (presuming that we are somewhat below WAT limiting conditions), especially if the intersection remaining slope is more downhill and the takeoff for the full length is first segment limited (for those of us who worry about first segment slope matching).
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Old 25th Oct 2010, 07:27
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J_T, would you be interested in completing the alphabet? I am sure there are number of items many of us did not discover just yet.

Sincerely,
FD (the un-real)

Last edited by FlightDetent; 27th Oct 2010 at 22:24.
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Old 25th Oct 2010, 14:56
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F D, Completing the alphabet.............

p) For APR equipped aircraft, why, under some circumstances use of APR OFF instead of APR ARMED can improve the Max Takeoff Weight? (APR fitted aircraft included to bring Mutt in).

Think time over...........

This can occur when Accelerate-Stop limited. If the Takeoff can be accomplished for a given weight at APR OFF instead of APR ARMED the V1 is lower due to Vmcg considerations. The Net thrust up to Vef will be the same in all cases, as APR does not 'kick in' until engine failure. Vef will be reached at the same point on the runway, but as V1 is lower, accelerate-Stop is improved due to greater ASDA remaining. If APR had been armed, V1 would occur further down the runway with less ASDA remaining, thus, in an Accelerate-Stop scenario, the lower thrust rating will produce the greater RTOW.

Another consideration is that between Vef and the pilot taking 'Stop' actions, at the lesser thrust with APR OFF less runway is consumed at the lower acceleration between Vef and RTO actions..

Similar discussion applies to the use of Thrust Derates, particularly on contaminated runways.

Item q) is up for grabs...... 10 letters to go

Regards,

Old Smokey
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Old 25th Oct 2010, 16:18
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Sub Part Q!

This is one for OS to add to if the mood takes him; I think it was his line a while back and not one I had thought about before, but which made me pay attention!

Why flying fast on Improved/Increased V2 after an EF is dangerous - particularly when limited by a close in obstacle - and even more particularly when using wet figures.

Maybe it's obvious.

mcdhu
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