Acceleration segment during climb to missed approach altitude

[A37575]

Question came up recently. During either an all engines or one engine inoperative missed approach, is the correct procedure to climb to the missed approach altitude first with go-around flap setting, before accelerating to clean configuration? Or is it true to say that the published missed approach procedure has an inbuilt allowance for an acceleration segment during the climb to the missed approach altitude?

[rudderrudderrat]

Hi A37575,
Try searching something like: Go around, thrust reduction altitude oei [Archive] - PPRuNe Forums (http://www.pprune.org/archive/index.php/t-523359.html)

PANS OPS 4 does NOT include an allowance for a level acceleration any more. It is up to the operator to ensure you can make the published GA gradient.
We can generally outperform the published gradients with all engines operating, so accelerate at our normal AA. (1,000' agl)

We have to do a calculation before each OEI approach to prove we can make the minimum gradient, and then only accelerate at MSA, or the first published stop ALT or at the acceleration Alt if published (eg. Grenoble).

[vilas]

Although with OEI climbing to missed approach altitude or MSA is correct Airbus recommends to find out if it is possible to accelerate and clean up before that.

[A37575]

Hi A37575,
Try searching something like: Go around, thrust reduction altitude oei [Archive] - PPRuNe Forums


Thanks a million RRRat. Excellent reading.:ok:

[Trackdiamond]

The basic ethos prevails in my opinion...A.N.C. The Acceleration Altitude is part of "A".The Missed Approach Altitude is part of "N" and so we might wish to consider prioritizing performance over navigation.This calls for TOGA to 1500ft AAL then accelerate and climb to the first limiting Missed Approach Altitude.For turboprops,due to 2nd segment climb limit a lower acceleration altitude would be used like 800ft for all engines and possibly as low as 400ft for OEI I a worst WAT limiting scenario.
The Approach and Landing requirements as per FAR 25.119 and JAR 25.119 contains the requirements for the all-engines oprating case.These state that,in the landing configuration,the steady climb gradient must not be less than 3.2%,with the engines at the thrust,power,that can be attained after moving the throttles from Minimum Flight Idle to Take Off power,within 8 seconds.

FAR 25.121 and JAR 25.121(d) gives the Discontinued Approach requirements.These state that,for a configuration where. Vs is no greater than 110% of Vs for the related all-engines landing configuration,yje steady climb gradients must not be less than 2.1% for twins,2.4% for Tri-jets,and 2.7% for four-engined aircraft. The associated conditions are:

1) Critical engine out,and the remainder at the available takeoff power or thrust
2)Maximum Landing Weight
3)A normal established speed for landing,not less than 1.5Vs
4)Undercarriage UP.

Discontinued Approach for aircraft certified to use a DH of less than 200ft must have a gross gradient of climb not less than 2.5% with the following conditions:

[Trackdiamond]

...continued

Accompanying conditions being:

1) Critical engine out, remainder at Max Contingency Power,
2) Either the final approach configuration for all engines operating or in the configuration that can be achieved within 1200m HORIZONTALLY from the start of the procedure for a Discontinued Approach,with engine failure late in the aproach;
3)A speed not less than 1.2Vms, or for four-engined aircraft where the application of power results in a significant reduction in Vs,1.15Vms,where this latter value is appropriate to the configuration as specified for the aircraft type for a one engine out Discontinued Approach procedure.The speed must also be NOT LESS than Vmcl for the configuration.The speed should also be NOT GREATER than the recommended Decision Height Speed.

[Trackdiamond]

For the Baulked Landing requirements specify that,at the runway altitude,the gross gradient of climb must be NOT LESS THAN 3.2% in the folowing conditions:

1)All engines at Maximum take off power and at a power not greater than 8 seconds after starting the Baulked Landing procedure with the engines and thrust-reversers(or reverse pitch for turboprops) in the most adverse setting that can be obtained during the approach and airborne element of the landing
2)The landing configuration,or such other approved configuration that my be attained 5 seconds after the start of the Baulked Landing procedure
3)A speed NOT LESS THAN 1!2Vms or for four-engined aircraft where the application of power results in a significant reduction in Vs,1.15 Vms,where Vms,is apropriate to the selected configuration for the procedure.The speedmust also be NOT LESS THAN Vmcl, as appropriate to the configuration for a one engine out landing,NOR must it be greater than Vat.
Vms is the minimum speed in the stall
Vmcl is the Minimum Control Speed for Landing Approach,All-engines case.

[john_tullamarine]

But ..

(a) if the terrain is benign .. not much of a concern

(b) if the terrain is nasty .. all bets are off.

The missed approach and landing climb WAT limits are there just to make sure you can go up .. just ... but without ANY consideration of terrain and CFIT. That's up to you (in reality the operator's ops eng folk).

In general, for nasty runways, the ops eng section will run a range of calculations to provide adequate terrain clearance. Fortunately, these days, tracking is not too much of a concern in the miss.

[de facto]

The missed approach and landing climb WAT limits are there just to make sure you can go up .. just ...

Hence a max runway slope of 2 % ?:p

[underfire]

As JT stated, EO climb is based on certain criteria, namely ISO temp and alt.

Get it hot out, and you are going no-where very fast. I have seem many, many climb gradients when it get to be 30-35 that are in the 100'/nm range, add some alt, like in China, and you get to the 50-60'/nm range.

Dont forget to take into account the add to the DA/MAP so you dont bust the MDA trying to get the thing to start climbing again. 50' momentary descent while EO? or on a hot day..no way.

This is one of the major reasons you see the much higher DA's with a tailored procedure, the EO missed part of the adventure.

[john_tullamarine]

Hence a max runway slope of 2 %

Slope is one of the inputs considered by the ops engineering folks. For some aircraft, considering takeoff in particular, runway slope can be the critically limiting case for takeoff (ie first segment limiting).