smartt1982
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Acceleration Segment On A Missed Approach

Sun May 13, 2012 7:16 pm

Where do you accelerate on a missed approach unless there is specific instruction when to do so/emergency turn?

On a normal departure (for most departures on NADP2) our procedures instruct us to bug up at flap retraction altitude.

On a go around we do the same, by accelerating at our flap retraction altitude i.e. below MSA are we compromising out terrain clearance or was this taken into account by the approach designers eg PANs OPS.

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longhauler
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RE: Acceleration Segment On A Missed Approach

Sun May 13, 2012 9:19 pm

This is a good point, and one that is hard to answer. At my airline, it is SOP to climb to at least 1500'AGL before accelerating on the published missed approach, or higher in special procedure airports. This also includes an engine loss in the go-around scenario.

The reason is exactly as you state, as protected airspace becomes a grey area in a missed approach.

For example, say you are landing on runway 09. You appear to be catching the traffic ahead, and ATC gives an amended missed approach clearance (should it be necessary) of turning to heading 360 (90 degrees to the left) and climbing to 3000'AGL.

When would you start that turn? At 400', at 1500' or at minimum sector altitude? Technically, it is MSA, as ATC is not responsible for terrain clearance? What if you turned at 400', then lost at engine, and climbed at 200 fpm to a min clean speed .... yikes!
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CosmicCruiser
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RE: Acceleration Segment On A Missed Approach

Sun May 13, 2012 10:26 pm

Quoting longhauler (Reply 1):
For example, say you are landing on runway 09. You appear to be catching the traffic ahead, and ATC gives an amended missed approach clearance (should it be necessary) of turning to heading 360 (90 degrees to the left) and climbing to 3000'AGL.

When would you start that turn? At 400', at 1500' or at minimum sector altitude? Technically, it is MSA, as ATC is not responsible for terrain clearance? What if you turned at 400', then lost at engine, and climbed at 200 fpm to a min clean speed

In the scenario you just gave you would turn at the time the tower says "XYZ go around" ; if you miss due to weather it would be at the DH/DA; if you miss for any other reason while making the app you can climb at the moment you realize you "ain't" going to land. For us at least, the clean up on a miss is flaps up after go around thrust but further clean up and accel is just as a t/o. The speed you accelerate to must be considerate of whether holding is a possibility or do I plan on making another app or I'm I outta here.
 
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longhauler
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RE: Acceleration Segment On A Missed Approach

Sun May 13, 2012 11:52 pm

Quoting CosmicCruiser (Reply 2):
In the scenario you just gave you would turn at the time the tower says "XYZ go around" ; if you miss due to weather it would be at the DH/DA; if you miss for any other reason while making the app you can climb at the moment you realize you "ain't" going to land. For us at least, the clean up on a miss is flaps up after go around thrust but further clean up and accel is just as a t/o.

If you turned at DH to anything other than the published missed approach (for example a 90 degree turn to the left), then you are in unprotected airspace.

Acceleration on the published missed approach, technically can be anywhere. By default, in the FMS it is 1500'AGL. This of course can be altered at special procedure airports. But ... this is where the grey area begins, if you are doing anything other than a published missed approach, technically you should not turn until you have reached MSA, so acceleration probably should wait until then as well.

So if the tower gave you the instruction, "Go - Around, turn to heading 360, climb to 5000", they are not responsible for terrain clearance, you are ... probably best to wait to MSA before you turn.
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CosmicCruiser
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RE: Acceleration Segment On A Missed Approach

Mon May 14, 2012 2:02 am

Well this is a little crazy because we're kinda going two different ways. Most turns on dept or a miss are never below 400'agl so I wasn't even thinking off anything else. My comment may have been misleading when I said "at D/H/D/A but I was referring to the MAP. With accel and turning as part of the topic I was going two directions. I actually had a similar situation at CDG on night. It was CATI mins and the tower says "there will be a dept prior to your ldg". We acknowledge. A moment later we hear Fedexxxx in the event of a missed app. turn right 360 climb 3000' msl".At about 300'agl still IFR we get Fedex go around. We just do our standard miss, max power, flaps 28, positive rate, gear up, set missed app alt. 500' hdg select, a/p on. So sorry that I was thinking in too many directions with that prev. post. No turns below 400' but above it anytime, clean up on sched. consider holding speeds. Whew!
 
Mir
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RE: Acceleration Segment On A Missed Approach

Mon May 14, 2012 2:10 am

Quoting smartt1982 (Thread starter):
Where do you accelerate on a missed approach unless there is specific instruction when to do so/emergency turn?

What does the SOP or flight profile for your aircraft tell you? That would be the place I'd start.

I would also say that if you're not in an engine-failure situation, then you're not really going to be performance critical, so if you're worried about terrain, I'd just wait until you're at the assigned altitude before accelerating and retracting the flaps. That would really only be applicable in IMC - if you're VMC you can just see and avoid the terrain.

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glen
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RE: Acceleration Segment On A Missed Approach

Mon May 14, 2012 9:36 am

Unless otherwise stated, the minimum required gradient for a missed approach is 2.5% for the whole procedure.
On a all-engine missed approach this is never a limiting factor, even with a clean-up wherever you have to do it according your SOP.
Problems arise on a one-engine out MA. Depending on weight, altitude and temperature the 2.5% can be very limiting. In this case you can not clean-up the aircraft wherever you want. You have to verify terrain clearance (MSA, minimum holding altitude, radar, visual) before clean-up or you might undershoot the terrain clearance floor.
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KELPkid
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RE: Acceleration Segment On A Missed Approach

Mon May 14, 2012 8:16 pm

I thought you accellerated the moment you go missed? Every aircraft I've ever flown requires that power be added to clean up from an approach/landing config to get the plane back into climb config and climbing again...and as a natural consequence of cleaning the bird up, you do go faster. But of course, you have rules to obey (max. speed below 10,000' in the US is 250 KIAS, and sometimes lower depending on the class of airspace you are operating in).
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longhauler
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RE: Acceleration Segment On A Missed Approach

Mon May 14, 2012 10:06 pm

Quoting KELPkid (Reply 7):
I thought you accellerated the moment you go missed? Every aircraft I've ever flown requires that power be added to clean up from an approach/landing config to get the plane back into climb config and climbing again...and as a natural consequence of cleaning the bird up, you do go faster.

Not really. Think of the chain of events on a missed approach.

From the MAP, you apply TOGA thrust, and reduce flaps, when you are in a positive climb, you retract gear. At that point you would be doing about Vapp +25 knots. (That actual name of that speed varies with aircraft type, so just imagine if you approached at 140 knots, now you are climbing at 165 knots, gear up, with flaps around 20 degrees, or Config 2 in an Airbus).

That is your missed approach climb out configuration. In that configuration you are likely climbing at around 2000 fpm, in a nice safe angle of climb, .... and the point of this thread, is at what point do you accelerate past that and start cleaning up. As you clean up you become more efficient, but ... your angle of climb becomes much less steep.

The point I was making is that as long as you are doing a published missed approach, your airspace and obstacle clearance is protected, thus you can clean up. If you turned to something other than the published missed approach heading, it would be better to stay at that missed approach configuration, slow speed, flaps 20, 2000 fpm to a safe sector altitude ... then start cleaning up.
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