Engine out terrain clearance

[Skyjob]

For the purpose of take-off performance analysis, the end of take-off flight path is considered to be when airplane reaches at least one of:
* A Fix and minimum altitude from which an approach may be initiated back to the departure airport or from which it is possible to proceed to departure alternate
* MSA
* Minimum en-route altitude for a route to departure alternate
* Minimum Radar Vectoring Altitude

An engine out take-off flight path and obstacle analysis method is based on AFM Net flight path, which clears all obstacles by 35 ft vertically and OPS 1 obstacle assessment area, centered on the intended flight track, within which all obstacles must be cleared vertically.

Development of contingency procedures, required to cover the case of engine failure or an emergency in flight which occurs after V1, is the responsibility of the operator, in accordance with Annex 6. Where terrain and obstacles permit, these procedures should follow the normal departure route.

When it is necessary to develop a turning procedure to avoid an obstacle which would have become limiting, then the procedure should be described in detail in the appropriate operator's manual. The point for start of turn in this procedure must be readily identifiable by the pilot when flying under instrument conditions.

The minimum obstacle clearance equals zero at the departure end of runway (DER). From that point, it increased by 0.8 per cent of the horizontal distance in the direction of flight assuming a maximum turn of 15°. In the turn initiation area and turn area, a minimum obstacle clearance of 90 m (295 ft) is provided. Where precipitous and mountainous terrain exist, consideration is given to increasing the minimum obstacle clearance.

The procedure design gradient (PDG) is intended as an aid to adjust the route with the intention of minimizing the PDG consistent with other constraints. Unless otherwise published, a PDG of 3.3 per cent is assumed. The PDG is not intended as an operational limitation for those operators who assess departure obstacles in relation to aircraft performance, taking into account the availability of appropriate ground/airborne equipment.

The PDG is based on:
a. an obstacle identification surface (OIS) having a 2.5 per cent gradient or a gradient determined by the most critical obstacle penetrating the surface, whichever is the higher; and
b. an additional margin of 0.8 per cent.

Published gradients are specified to an altitude/height after which the minimum gradient of 3.3 per cent is considered to prevail. The final PDG continues until obstacle clearance is ensured for the next phase of flight (i.e. en-route, holding or approach). At this point, the departure procedure ends and is marked by a significant point.

Whenever a suitably located DME exists, additional specific height/distance information intended for obstacle avoidance may be published. RNAV waypoint or other suitable fixes may be used to provide a means of monitoring climb performance.

[de facto]

That one gave me a much-needed chuckle. Maybe where you work the manuals are error-free and perfect

I havent read them in such details to know,but obviously the more mature the airline the more chance mistakes have been spotted and corrected.

In general and for large operators,as i mentionned,those manuals have been through some obvious thoughts and checked by the relevant authorities.

Now,what i meant was that blatently deviating from layed down and accepted SOP (especially perf calculated)is asking for troubles in the scenario bubbers described initially.
As written above,in a controlled emergency,i would not deviate from layed down engine out procedures just for the reason of guestimating that flying in cavok weather is sufficient to deviate from such escape routes.
BARKINGMAD,
Concerning your std setting of altimeter,yes there are times when some non standard actions are needed as the sops cant be written for every scenario possible but in your case,i doubt the noise abatement should take over the setting of your altimeter ...but you did the right thing to request clarification and thats how manuals evolve or get too fat
Im curious as what is your transition altitude/preferred noise (A/B/1/2) and SID level off FL?

[flyboyike]

Originally Posted by de facto

I havent read them in such details to know,but obviously the more mature the airline the more chance mistakes have been spotted and corrected.

In general and for large operators,as i mentionned,those manuals have been through some obvious thoughts and checked by the relevant authorities.

That's one way to look at it. Another way might be that the more mature the airline, the more opportunity there is for a bunch of decrepit fossils who haven't even seen a simulator, let alone an actual aircraft, in decades and decades to write pages upon pages of unadulterated nonsense, which their similarly decrepit buddies at the "relevant authorities" will gladly sign off.

True story.

[JammedStab]

Thanks for the replies.

This scene is what made me ask the question. The mountains are farther away than appears but there is a runway pointed at them.

Google Image Result for http://people.ucalgary.ca/~enstasiu/home/Calgary%20skyline%202012.jpg

So I would wonder, how close do they have to be to require a special departure procedure or how far away to not require a special departure procedure.

[BOAC]

I think from memo the cumulo-granitus is a bit more than 25nm, so achieving Calgary 25nm MSA would be a start. Also an impossible question to answer - the runway may point at the Rockies but the route may go the other way, so presumably once you are clean - and armed with rudimentary terrain knowledge - you would be looking at heading east in that case or achieving en-route MSA if heading west before you make a dent in them thar hills. It is not much different to departing a northern Italian airport towards the Alps.

[FullWings]

Mountains like you have at Calgary, Denver, Milan and the like, although spectacular, aren't that much of a problem as they are some distance from the airfields in question and are "obvious".

The nasty places, IMHO, have low hills close in which don't look that forbidding until you lose a donk. MSAs may not be particularly high compared with the airfield altitude but you still have to get there. ZRH comes to mind as somewhere that has seen more than its fair share of accidents, both on departure and approach.

[FE Hoppy]

ZRH comes to mind as somewhere that has seen more than its fair share of accidents, both on departure and approach.

And the locals have now a very thorough engine out SOP including a standard procedure for those rwys where it fits and non standard procedures where it doesn't. They also have procedures for engine failures occurring when already on the normal SID.

I'm quite certain they are not the only airline who does this. But I know from experience that there are some airlines who don't.

[Basil]

Yes, Bogota. Long time since I've been there but ISTR that, on one runway, the procedure turned you into approaching traffic (or was that the GA?).
Anyway, it seemed to me that, if VMC, it would be best to head off down the valley

[aterpster]

Best ever tutorial on performance:


FAA Workshop on Transport Airplane Performance Planning | Aircraft Climb Performance Videos | NBAA - National Business Aviation Association

[bubbers44]

Defacto, You seem to believe every thing told you so must be young. Yes I went to our chief pilot and told him our new sop into TGU would mean we couldn't land 90% of the time because we needed to exceed 1000 fpm to land unless we had at least a 15knot headwind. He agreed and just said just keep doing it the way we have always done it so sop is a guideline, not a law. In the future don't be so negative about us old guys. We survived a career with no scratches. Hope you do too.

[de facto]

Defacto, You seem to believe every thing told you so must be young

It'd think you would know what my screen name means...but obviously not

Yes I went to our chief pilot and told him our new sop into TGU would mean we couldn't land 90% of the time because we needed to exceed 1000 fpm to land unless we had at least a 15knot headwind

Are you talking about sink rate issue at low altitude?well in that case it is not forbidden if briefed prior...your chief pilot should have had this included in your sops or training for this particular airport.

He agreed and just said just keep doing it the way we have always done it so sop is a guideline, not a law. In the future don't be so negative about us old guys. We survived a career with no scratches. Hope you do too.

I aint negative at all about old folks,i am negative about people who bull their crews about doing some non standard maneuver unbriefed,unapproved based on some personal assumptions...
I do know the difference between guidelines and law,however most guidelines come from the law...and disregarding sops in general treating them as mere guidelines is a state of mind that i deplore.

Many accidents result from loss of situational awareness,and following sops,especially in an emergency is a very important tool to maintain this awareness.

The nasty places, IMHO, have low hills close in which don't look that forbidding until you lose a donk. MSAs may not be particularly high compared with the airfield altitude but you still have to get there. ZRH comes to mind as somewhere that has seen more than its fair share of accidents, both on departure and approach.

Innsbruck was a 'fun' place to go...

[BARKINGMAD]

BRAIN FADE.

"Concerning your std setting of altimeter,yes there are times when some non standard actions are needed as the sops cant be written for every scenario possible but in your case,i doubt the noise abatement should take over the setting of your altimeter ...but you did the right thing to request clarification and thats how manuals evolve or get too fat
Im curious as what is your transition altitude/preferred noise (A/B/1/2) and SID level off FL?"

1) NA procedure will not take precedent over stop alt/FL, too much grief and paperwork after-I'll argue over the fine!

2) TA varies with the places I fly, SOP is to change asap if low level off FL.

3) Noise procedues are variable depending on dep airport, not permitted a preference.

4) As per the original query, I find it difficult to believe a professional pilot and their peers could write this into the manual!

My old brain begins to creak as I get airborne with MFRA, power cutback, acceleration/cleanup initiation, transition altitude, safety altitude and stop alt/FL all whirring around inside. 2 of these are displayed, MFRA on the PFD and stop alt/FL on the MCP, but the rest are on a piece of paper on control column/chart clip.

Is this really a sensible way to run a railway?

[underfire]

skyjob, all,

Sky, while you included all kinds of illustrations, they are for all engine analysis. EO procedures are classed as emergency, and there is NO criteria for engine out missed or departure design.

Typically, the EO procedure will follow the straight segment to an altitude, but that is simply to standardize the EO procedure with the all engine, assuming that you go EO at minima, and to get you to the same point as the missed to clear, and for ATC to react and provide some assistance.

The EO procedures, beginning with the EO missed approach, are very complex in nature. Analysis begins with the aircraft climb perf, assuming the worst case variables for the climb. This is MLW, all bleeds on, and max temp at the airport.
There are many airports, terrain rich, or high altitude where an EO procedure is not possible. If you are EO enroute, you are diverting to an alternate, because you cannot go missed on approach.

With a coded procedure, EO missed is taken into account with the DA. Many people wonder why the standard approach has a 250 HAT, while the coded approach has a 1200 DA, and EO missed may be the reason.

As an example, at a certain airport in China, the EO missed is over 400nm long to get to the alternate. Terrain/obstacles were analyzed for the entire procedure.
Cuzco EO missed RW28?



EDIT, Terpster..the video you posted was very interesting, especially at around 11 mins and the FAA explanation of the EO procedure on the Jepp plate. I had no idea that the EO procedure, even though shown on the plate, was not FAA approved, that the individual airline had to engineer and approve itself to use this.

[underfire]

terpster, I would highly recommend the video. The guy from Boeing, beginning at about 1 hr:55 mins. It was always difficult to explain this issue to the pilots especially that the performance charts do not include any winds whatsoever.

[FullWings]

I aint negative at all about old folks, i am negative about people who bull their crews about doing some non standard maneuver unbriefed, unapproved based on some personal assumptions...

I do know the difference between guidelines and law,however most guidelines come from the law...and disregarding sops in general treating them as mere guidelines is a state of mind that i deplore.

Many accidents result from loss of situational awareness,and following sops,especially in an emergency is a very important tool to maintain this awareness.

Well said Sir.

I'm all for free thought, suggestions, doing it differently, etc. but you'd better have a lead-lined, copper-bottomed mother-****** of a good reason to roll your own ET on the spur of the moment.

It's interesting listening to a briefing where someone gaily says something like "In the event of blah blah, we'll do a visual circuit or turnback onto RWY XXX". Fine in a PA28 but if you're down to one engine and one hundred tonnes over MLW, just how are you going to do that? It is well outside most people's experience, I would suggest, so it's going to be a real voyage of discovery as new facts about bank angle, turning radii, monster Vrefs and bugger! I can't slow down! are all found out about on the fly. Also, one of the major possibilities when you're gunning for a rapid return is that there is uncontrollable smoke on board. Now we're doing it all with Aliens on our faces!

Much as de facto says, there's a big breakdown in CRM and SA when non-standard emergency procedures are initiated for no really good reason apart from "because I can". That's not to say that on very rare occasions some thinking and action outside the box might be required but that should be obvious to all on board. Our FCOM begins with (paraphrased) "These are the rules, break them if you must to stay safe."

[underfire]

FW, your reasons are exactly why there should be a coded EO procedure in the box. While the crew is sorting out the issues, at least there is some knowledge that the aircraft is on a path that has some protection.
While I think that following the SID might work for EO Missed, I would never assume that following the SID for EO DEP would provide protection, especially if there are turns.

[Skyjob]

Underfire, the illustrations were provided to allow fellow pilot to e what they may not have seen before when considering how departure procedures are defined.

You are correct that an EO does no take these into account, merely terrain clearance requirements. For best vertical gains straight out departures are usually considered to best as the aircraft does not limb as well during a turn, in case of EO may no even limb at all in a turn.

EO procedures clear obstacles and terrain by minimum requirements underneath the considered flight path, whilst attempting simplicity or pilots as their workload is already high enough at these times.

Coded Eo procedures are commonly not possible as the FMC data is refreshed and loaded each 28 days, in line with AIRINC cycles, but EO procedures are type/operator specific and can only be loaded inoto FMC using Supplementary database, something that needs creating/monitoring/updating/installing/maintaining etc, some operators do not or can not spend resources on that. Granted, coded EO procedures would be better provided the aircraft can fly them (limiting bank angels, re-executing a new FMC selection of route, etc etc)

[aterpster]

skyjob:

You are correct that an EO does no take these into account, merely terrain clearance requirements. For best vertical gains straight out departures are usually considered to best as the aircraft does not limb as well during a turn, in case of EO may no even limb at all in a turn.

At many locations turns are required in OEI procedure. Track design is predicated on any turn being made at a 15 degree angle of bank, which results in very little loss of lift.

[underfire]

skyjob:

Any coded procedure is on the cycle. If it isnt updated, it cannot be used. All coded procedures go through the navdatabase provider, they are not sent to the individual airline for upload. The code has identifiers per aircraft, and will not load to a different aircraft

The EO procedures are coded as part of the procedure, ie the EO missed is coded with the Approach procedure, just the same as the missed, it is not separate.
The EO DEP are the same, coded with the DEP.

All procedures are monitored daily for NOTAM, additional obstacles, and error checked each cycle before sent out by the provider. This is a costly struggle to maintain the integrity on the cycle, and there are many differences between the numerous navdatabases to account for.

As terpster stated, there are virtually always turns with an EO procedure, with bank altitude and bank angle limits to account for the degradation in a turn. In the video linked by Terpster, it was rather interesting to note the EO procedure at Slat Lake City. I find it very difficult to believe that a twin could make that turn EO.

[Skyjob]

Unfortunately not all aircraft are capable of selecting a new departure procedure easily, I'm thinking if eg 737 which doesn't have a capable fmc for route 2 options at this time yet.

Regarding coding it in fmc through nav data provider, you are correct this is the chosen method of distribution.

Let's get this right, I'm not attacking anyone, but I think the capabilities vary and need to be taken into account.

The question wa about EO, that was and should be answered, nog about how it can or can't be achieved in a specific aircraft type or not.