Engine out missed approach acceleration

[wince]

I wonder if any OPS scholars can point me to the correct information:

I've been told that the missed approach acceleration altitude depends on what is written on the Jepp charts, PANS OPS 3 (1000 feet) or PANS OPS 4 (1500 feet). In my company we always accelerate at 1000 feet regardless.

If this is the case, is this also true for engine out?

Thanks,

W

[rudderrudderrat]

Hi wince,

Before Pans Ops 4, the charts GA procedures were OK for an aircraft which could do minimum 2.5% climb gradient. There was an allowance for a 7 miles level acceleration, then a further climb at 2.5% (I think) to the stop altitude.

Pans Ops 4 doesn't do the maths any more - it's up to the operator to ensure their overall gradient (including any level acceleration) meets the gradient specified on the chart.

[Slasher]

Just to add further to Rudderrat, in PANS OPS 4 the acceleration
segment have been deleted, as once published in ICAO Doc 8168
Vol 2 in all three Editions.

ICAO Pans Ops criteria doesn't take into account the case of an
engine out. The Designers only make the procedures for the all
engines case and it's a requirement of the Operator to develop
company aircraft and airport specific engine out procedures as
Rudderrat mentioned. However Pans Ops is quite stringent as far
as obstacle clearance goes - eg the standard departure climb
gradient is 3.3% and the missed approach gradient is normally
2.5%. Most modern aircraft can accomplish these gradients even
with an engine out.

(This is also in the case of a SID, in which the procedures are
designed with a continuous climb in mind. However in any SID
there is nothing to stop a driver from arranging his flight to
include an acceleration altitude as long as its been calculated
correctly. All that has to be accomplished is that the aircraft
remains above the Procedure).

[aterpster]

Slasher:

(This is also in the case of a SID, in which the procedures are
designed with a continuous climb in mind. However in any SID
there is nothing to stop a driver from arranging his flight to
include an acceleration altitude as long as its been calculated
correctly. All that has to be accomplished is that the aircraft
remains above the Procedure).

Indeed so, which is a very complex calculation that only professional performance engineers can perform. The result is often an OEI "escape" flight path that deviates from the SID.

FAA AC 120-91 is required reading for anyone with a serious interest in this subject. Although written for performance engineers is provides an overview for pilots.

[Slasher]

FAA AC 120-91 is required reading for anyone with a serious interest in this subject

We don't operate to FAA certs around here aterp, but is there
anywhere I can obtain that AC just for reference?

[MarkerInbound]

Almost everything the FAA prints is available on their web site.

http://rgl.faa.gov/Regulatory_and_Guidance_Library/rgAdvisoryCircular.nsf/0/55a6248632ed6e8d86257184005a2188/$FILE/AC120-91.pdf

[aterpster]

Slasher:

We don't operate to FAA certs around here aterp, but is there
anywhere I can obtain that AC just for reference?

Advisory circulars of this type provide guidance and, as such, are not regulatory. I suspect performance engineers in many places other than FAA-dom are using AC 120-91.

Another example is FAA Order 8260.52 that provides criteria for RNP AR IAPs. It is being widely used outside the U.S.

[7478ti]

No.

It may be airline and aircraft type specific, or even configuration specific (.e.g., E/O).

For US rules and Op-Specs under FAR 121,... see AC120-29A.

There is a long history on this...and it is not comprehensively addressed,... by either TERPS or PANS-Ops

[john_tullamarine]

Indeed so, which is a very complex calculation that only professional performance engineers can perform. The result is often an OEI "escape" flight path that deviates from the SID.

Whilst the comment might be flattering to the egos of ops engineers and cause us to acquire swelled heads, the reality is that routine runway analysis work is not terribly difficult ... but certainly does require meticulous attention to detailed housekeeping. The situation in the missed approach is a little more complicated due to the need to figure out where the aircraft might be during the transition - far easier in these days of high accuracy navigation systems.

There is no reason why a pilot, for instance, with a modicum of basic technical training, cannot do the job just as well as (and, in some respects, better than) the specialist engineer. However, the oft-inferred suggestion that Captain Speaking can do the task as part of the preflight checks is probably a bit wide of the mark. A manual assessment for a difficult runway can take many, many hours of tedious work.

Another problem relates to the inability of most aircraft to maintain a constant climb OEI - ie there needs to be an acceleration phase for reconfiguration and, depending on the speed delta between initial and fnal climb speed, that acceleration can take a LONG time and distance OEI. Older twins are a case in point.

[Slasher]

Thanks for that URL Marker.

I worded it as "arranging his flight..." to cover any methods
of calculation arrival, be it a performance engineer or pilot. I
did not infer that the pilot necessarily does it all himself - as
John mentioned it would take an extraordinary amount of
time to complete it.

[FlightPathOBN]

JT,

I think that while a pilot could a broad brush perf climb, there are many variables, with bleeds, icing, temperatures, and specific engine configurations...that would make it very difficult... BCOP case in point.

[john_tullamarine]

I defer to your acknowledged background in these matters.

However, I've know several pilots without engineering tickets who were more than competent in runway analysis. The mechanics of the thing tend to be more boring than anything else. The interest lies in getting the obstacle data right .. although that, too, is becoming easier with improving technology.

Where the typical pilot might start to run out of steam is in the routine performance work associated with operational optimisation and so forth.

On the other hand, it probably makes more sense to have engineers (preferably with piloting backgrounds) do the RTOW work ?

At least three such in the PPRuNe fraternity come to mind.

[aterpster]

j.t.

I defer to your acknowledged background in these matters.

However, I've know several pilots without engineering tickets who were more than competent in runway analysis. The mechanics of the thing tend to be more boring than anything else. The interest lies in getting the obstacle data right .. although that, too, is becoming easier with improving technology.

Where the typical pilot might start to run out of steam is in the routine performance work associated with operational optimisation and so forth.

On the other hand, it probably makes more sense to have engineers (preferably with piloting backgrounds) do the RTOW work ?

At least three such in the PPRuNe fraternity come to mind.

One of my work associates is a biz jet pilot and a real expert on AC 120-91 and OEI requirements overall. He and some other real experts in the field have been meeting recently over the issue of lack of meaningful navigation guidance for an extended takeoff flight path and transition to en route requirements at airports with significant, high terrain all around.


The transition to RNAV for this purpose has fallen horribly behind. The typical performance engineer doesn't understand performance based navigation. And, in the U.S. at least the typical procedures specialist doesn't understand the extended OEI case. In some cases they are still using VOR facilites that cannot be received, or in some cases where then can, they are in a sector of restricted radials.

My view is that you need site-specific collaboration between a performance engineer, a terps (or pans-ops if you will) specialist, and a technical pilot to provide an RNAV performance based navigation (PNB) solution to the complex, extended takeoff flight path all the way into the OEI en route environment, and then with the option of tactical diversion while en route.

In the U.S. FAR 121.91 is terribly obsolete. Although there may still be a requirement to provide +/- 5 statute miles en route lateral protection for "DC-6" OEI en route ops in the mountains, it is absurd for the PNB capable aircraft. Something on the order of +/- 2 nautical miles would be more in order, with provision for reductions from that for the more cabable PNB capable aircraft.

121.191 has lighted airways and DC-6Bs (perhaps even DC-4s) embedded in its arcane provisions. I suspect the rest of the world is no better off, for the most part.

[Zeffy]

aterpster. :D:D:D

[john_tullamarine]

My view is that you need site-specific collaboration

Absolutely. There won't be too many folk around who are appropriately competent in the multiple fields - co-operative efforts offer significant potential.

[aterpster]

OK465:

(minor unavoidable conflicts with some .52 provisions accepted by the using authority)

That is to be expected with justification of an equivalent level of safety. As I recall that procedure is for only one or two airplane types, which gives the proponents the fair opportunity to work to specific aircraft capabilities.

[Piltdown Man]

My understanding is that there is only one missed approach profile and it doesn't matter if it is executed all engines or one down. Our SOP is to accelerate at the final Missed Approach Altitude unless... there is possibility of operating the engine beyond the GA time limit AND you are above the MSA. We'll also (potentially) fly the non-standard N-1 lateral track if forced to go-around below DH/MDA.

PM

[nzpilot]

Hi guys
I am trying to get my airline to sort out a single engine missed approach procedure for HKG. We fly B777
Our typical early morning arrival is for 07 left with temps in summer around 25 to 30 Celsius .
The missed approach gradient for the lowest minima is 7% or close to it. The B777/200 will not do anything like this, at typical landing weights.
I reckon we should have a SE missed approach route published.
Could you experts give me some ideas, to further my case with the fleet office, and performance engineering.
Is it an ICAO requirement for airlines to publish procedures where a MAP gradient is shown on the chart?
I would appreciate it if some other regular HKG operators could give me some idea of their procedures.

[Fratemate]

Our OEI for HKG reads:

07L: When SMT available: Climb on track 073 to SMT. At SMT turn right direct to ROVER then turn right onto track 182.

When SMT unavailable: Climb on track 073 to IZSL D8.5 (northeast of ROVER) then turn right onto track 182.


07R: Climb on track 073 to PORPA then turn right onto track 182.

Flap retraction should be initiated at or above 1300' MSL to clear obstacle.




This is for engine failure on takeoff and OEI during missed approach and applies to A320, B747, B767, B777 & B787.

[flyburg]

Hello nzpilot,

My understanding of the regulations is that in the dispatch fase you need to comply with the approach climb limited weight and the landing climb limited weight. If the climb gradient of the lowest minimum can than not be met and the weather is at those minimums than that airport is below minimums for you. You can either select two alternates or reduce your weight to a weight where you can comply with the climb gradient. In actual flight it becomes a different story.

At my airline a check is made before each departure by dispatch to make sure we comply with al those weight restrictions, and if any is found limiting it will be put in the operational flight plan header.

Hope this helps!