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Pin Head
16th Sep 2015, 15:45
To meet terrain clearance criteria, would you agree on the lower of

1. Published missed approach minimum holding altitude (if any)
2. Sector MSA
3. Published missed approach stop altitude

Thanks

Pin

FlightDetent
16th Sep 2015, 16:01
I concurr.

Other than that, comapany tells me that formally, to cover for all eventualities, it is 3. This claim is supported by a change in PANS-OPS about 5(?) years ago.

respectfully, FD.

RAT 5
16th Sep 2015, 16:05
I would have thought it depends where you are: and what has SE got to do with terrain safety clearance; or am I missing something?

The published MAA stop altitude assumes you follow the MA routing: the MAH assumes you're in the relevant hold: the MSA covers you anywhere within the prescribed area. Or am I confused about the question?

Togue
16th Sep 2015, 16:56
Your company should have a Max Acceleration Altitude on the Take Off Charts. And they should also have a policy for SE max acceleration altitude.

FlightDetent
16th Sep 2015, 20:06
RAT 5:

I am not sure what makes PH raise the question in first place, this would be my example scenario however (loosely based on an existing airport):
ELEV 3000
MSA 11000
MAA 7000
MHA 9000
CIRCL 4200

MisApch procedure is terrain restricted and calculated i.a.w. recent PANS OPS, that is without any level acceleration segment. Your SE performance will give you 2,8 % at 500 ft AAL, and GA/TKOF PWR is time limited so that you cannot use it all the way to 7000 within the allowed interval. When to accelerate? Myself I do not have the answer. Yet, for various reasons, to be perhaps discussed later, am actually happy with that.

Togue:
I would be greatly interested to hear an example of such policy, honest. I can think of several more or less tailored "strategies" but not really a policy. Assuming the above scenario with OEI TKOF calculated MaxAccAlt = 5500 for given weight and conditions for instance.

Yours, FD.

safelife
16th Sep 2015, 21:42
How about not accelerating. Maintain speed, TOGA as long as you may or require (10 minutes max probably), reduce to MCT after that, and come back to land remaining in proximity of the field.
That's what we did on biz jets, without all the fancy charts EOSIDs airlines do provide. Worked anywhere.

john_tullamarine
16th Sep 2015, 22:49
An interesting discussion worth continuing ..

GA/TKOF PWR is time limited ... When to accelerate? ... I can think of several more or less tailored "strategies" but not really a policy ...

FlightDetent has identified the principal concerns .. again, this is one of those problems best addressed by the ops engineers in advance (with procedures published for line use) .. and not by the line folks on the day.

Also, keep in mind that the gradient capability at the miss deteriorates progressively as the aircraft climbs .. one needs to do a bunch of sums for any difficult runway escape if one wishes to have some reliable probability of getting through the day without bloodshed .. matching PANS/OPS with OEI operations is not a straightforward matter, I suggest.

How about not accelerating. Maintain speed, TOGA as long as you may or require

See above .. in extremis, one would be unkind to the remaining motors as may be necessary .. they are unlikely to let you down even if subsequent maintenance might be expensive ..

A sensible and defensible plan developed in advance makes for a better pulse rate, is not difficult, and just may save the day .. ?

That's what we did on biz jets, without all the fancy charts EOSIDs airlines do provide.

The pocket rockets usually have the saving grace of more get up and go than their larger brothers and that generally leads to such an attitude.

Worked anywhere.

The difference between planning and gambling .. ?

RAT 5
17th Sep 2015, 12:55
FLT-D. My apologies, as I read PH's question again; but I'm still not quite sure about it. The title is "SE go around flap retraction altitude". He then goes on to discuss terrain clearance altitude. I do not see the connection. SE flap retraction altitude is a procedure specified by either manufacture or operator, commonly 1000' agl. Climb gradient, SE, upto an altitude before accelerating would be a specific local procedure for obstacle clearance. ZRH comes to mind. Terrain clearance after the go around is for any engine case and depends where you are. Hence, still, my confusion behind the question.

de facto
17th Sep 2015, 13:42
You airline,if it is a scheduled airline.... should provide you with Minimum flaps retraction Heights for each airport/runway you are flying in and out of.
They are normally linked to a given Engine Out Sid routing.
These are minimums,if you are lucky enough to fly Airbus, the latter provides Max flaps retraction heights.

If you are not provided Max flaps retraction ones,you can use your Toga single engine limit (normally 10 mins),if needed on the day.
Normally MFRA s are rarely higher than 2000 AAL unless specific airports with high terrain on the departure area such as Innsbruck.
So you rarely need the 10 mins.

If you are not provided MFRA nor EOSID then the runway track is used to 1500 AAL or MSA if higher,i(standard AFM),in that case you can either accelerate at 1000 ft AAl (standard boeing training accl),if no terrain in the departure path,or when reaching your initial altitude ,normally higher than the sector MSA.

vilas
17th Sep 2015, 13:54
OEI is a different consideration. But even with AEO according to airbus if missed approach altitude is high operator should find out if it is possible to accelerate and climb to MA clean. I think that's what JT also said. I do remember Jet Star Australia person explaining that for one Australian or New Zealand airport they continue TOGA for 5/10Mts. then recycle MCT and to TOGA again.I was quiet surprised with this method. Can anybody throw some light on this?

RAT 5
17th Sep 2015, 17:32
The question is about a SE GO Round not a V1cut then following an emergency turn. Normally a twin engine a/c will follow the STD MA routing if made at or above DA. If not, then there will be special published routes by either the airfield or operator.
I'm not sure we are all discussing the original question. I think we need more info from PH about what is really being asked.

john_tullamarine
18th Sep 2015, 11:00
then recycle MCT and to TOGA again

Is that right ? I guess CASA engineering was never in on the discussion ? I suspect, as well, that the OEM might not have provided an NTO ?

underfire
18th Sep 2015, 11:06
matching PANS/OPS with OEI operations is not a straightforward matter, I suggest.

Exactly, as OEI performance is not considered in the public design criteria.

john_tullamarine
18th Sep 2015, 11:22
Perhaps missed my point .. the difficulty is endeavouring to make OEI work OK ...

Pin Head
19th Sep 2015, 03:36
thanks for reply.

its very interesting to read what is being posted.

some have some idea of what is going on and equal some thinking is required for some responses.

i understand that different authorities have different laws and policies.