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-   -   Engine out Go Around ACC ALT Twin JET EASA, ICAO (https://www.pprune.org/tech-log/660235-engine-out-go-around-acc-alt-twin-jet-easa-icao.html)

StudentKaro 10th July 2024 09:38

Engine out Go Around ACC ALT Twin JET EASA, ICAO
 
Hello AV Friends
Problem in understanding - according to EASA and common law.

Question: (Twin JET) In case of one engine out go around - what is acceptable to law acceleration altitude for flap retraction?

Second question: (After take off engine failure, 2eng jet) What is the point that you must execute special engine out procedure or continue SID.

Thank you for pointing exact values and DOC where can find about above.

hans brinker 11th July 2024 02:21


Originally Posted by StudentKaro (Post 11693789)
Hello AV Friends
Problem in understanding - according to EASA and common law.

Question: (Twin JET) In case of one engine out go around - what is acceptable to law acceleration altitude for flap retraction?

Second question: (After take off engine failure, 2eng jet) What is the point that you must execute special engine out procedure or continue SID.

Thank you for pointing exact values and DOC where can find about above.

For my company:

Acc alt will be in the FMS, for both and single engine.
EOP or SID will be in Jepp company pages, including what to follow when.

Airline pilots don't follow the law, we follow company procedures that have been approved as compliant with the law by aviation authorities.

StudentKaro 11th July 2024 06:32


Originally Posted by hans brinker (Post 11694242)
For my company:

Acc alt will be in the FMS, for both and single engine.
EOP or SID will be in Jepp company pages, including what to follow when.

Airline pilots don't follow the law, we follow company procedures that have been approved as compliant with the law by aviation authorities.

Understood and with a high level of automation and options purchased by the operator for the fleet.

However, is anybody aware about DOC ICAO 8168 (MSA or GA alt whichever lower) or EUR OPS (OCH/OCA)? Some operators have 1000 FT RA as standard but there are some countries that require higher alt as a law.
Question is what height is the basis in the documentation that you use?

KingAir1978 11th July 2024 15:38

StudentKaro The EASA legislation is a little harder to navigate than the FAA legislation. This response is therefore based on FAA legislation.

The short answer to your question: your company should provide you with guidance on what to do in case of a go around with an engine out.

Follow this link: https://www.faa.gov/documentLibrary/...AC_120-91A.pdf To get to an advisory circular. Chapter 20 will provide you with some guidance.

The long answer:

There is a disconnect between what the airplane certification and the obstacle clearance in the design of a missed approach. The airplane manufacturer needs to demonstrate 2 requirements, of which the landing climb gradient is the one that is relevant to this discussion. A twin transport category airplane needs to demonstrate a 2.1% climb gradient (https://www.ecfr.gov/current/title-1...part-25#25.121 scroll down... § 25.121 (d) ) This needs to be demonstrated in N-1, gear up, critical engine inop, max. landing weight and a speed in accordance with the link.

The obstacle clearance is governed by different legislation. A obstacle clearance plane with a gradient of 1 in 40 needs to be provided for the missed approach, unless otherwise published. This equates to a 2.5% design gradient. For those of us who are still reading and paying attention... The plane manufacture thus needs to demonstrate a lower climb gradient than the obstacle gradient used in the design of the missed approach procedure. Moreover, the design gradient is for the entire missed approach and the missed approach climb gradient is more like a snapshot.

In other words, in case of a single engine missed approach you may not meet obstacle clearance. Under FAA law there is no specific guidance (see the first link), but there is a recommendation to provide flight crews with guidance on what to do in case of an engine out missed approach. My company provides me with this guidance.

Hope this helps.

Airmann 11th July 2024 17:00

Acceleration altitude is 3rd segment. Minimum alt for third segment is 400ft. So this is the lowest.

​​​​​​There will be a divergence point between regular and EOSID. It's at this point that the two SIDs follow different paths. Once past the divergence point, follow the regular SID. (disclaimer: this is how we do it where I work and we are EASA compliant though not in an EASA country).

KingAir1978 11th July 2024 18:04


Originally Posted by Airmann (Post 11694682)
Acceleration altitude is 3rd segment. Minimum alt for third segment is 400ft. So this is the lowest.

​​​​​​There will be a divergence point between regular and EOSID. It's at this point that the two SIDs follow different paths. Once past the divergence point, follow the regular SID. (disclaimer: this is how we do it where I work and we are EASA compliant though not in an EASA country).

3rd segment applies to take-off performance, NOT go around performance. That is a different animal.

hans brinker 11th July 2024 22:42


Originally Posted by StudentKaro (Post 11694298)
Understood and with a high level of automation and options purchased by the operator for the fleet.

However, is anybody aware about DOC ICAO 8168 (MSA or GA alt whichever lower) or EUR OPS (OCH/OCA)? Some operators have 1000 FT RA as standard but there are some countries that require higher alt as a law.
Question is what height is the basis in the documentation that you use?

The documentation I use as a pilot is the one provided by the company. The company will have people research every destination for local rules and regulations and (hopefully) would find about countries that deviate from ICAO standards. But that is far outside what is required of an airline pilot. I have emailed our tech department about an engine failure procedure that I felt (based on a bout a decade and a half of flying into mountainous terrain) was flawed, and it was revised, but not because of any legal problems, just the design could get you outside of the protected area as it was based on HDG, not track.

On an unrelated note, I highly doubt any operator would use 1000'RA, It would normally be HAA.


compressor stall 12th July 2024 09:45

I’d say the first question is a bit simplistic.

OEI approach.

Go Around at minima or Go Around at 50’. Two very different beasts wrt the subsequent track and guaranteed terrain clearance on the departure path.


sonicbum 12th July 2024 17:57


Originally Posted by StudentKaro (Post 11693789)
Hello AV Friends
Problem in understanding - according to EASA and common law.

Question: (Twin JET) In case of one engine out go around - what is acceptable to law acceleration altitude for flap retraction?

Second question: (After take off engine failure, 2eng jet) What is the point that you must execute special engine out procedure or continue SID.

Thank you for pointing exact values and DOC where can find about above.

Cheers,

Q1) Check DOC 8168 section 6 (if memory serves… don’t have it with me right now).
We discussed the OEI GA ACC alt several times on the prune over the past few years. Try a search and you should find loads of valuable posts.
Bottom line is you can start the acceleration when you comply with the requirements of the Final Segment. Usually airlines don’t bother and to keep it simple will just ask You to start the level acceleration once above MSA/GA ALT/MRVA whatever is lower. In some places like France you will find it written on approach charts, I.e. do not start level acceleration below XXXX feet.

Q2) Diversion point. That has to be evaluated by your perf-tech people. If nothing is written then once past the last common point EOSID and SID just follow what you are currently flying, I.e. engine out after the last common point keep flying the SID. Before fly the EOSID. You can’t deviate from the SID to rejoin the EOSID below MSA (especially in IMC) again unless your operator tells you to do it as they have evaluated the terrain.

Mr Good Cat 13th July 2024 08:19


Originally Posted by compressor stall (Post 11695063)
I’d say the first question is a bit simplistic.

OEI approach.

Go Around at minima or Go Around at 50’. Two very different beasts wrt the subsequent track and guaranteed terrain clearance on the departure path.

This is true, and the go-around gradient only accounts for a go-around from minima. However, you can always use an engine-out takeoff routing (if you have one available for the runway you're landing on). Easa (and I'm sure the FAA) also say that if you can't make the required gradient for the missed approach (due weight etc) then you have the option of using a takeoff engine-out procedure if you have one. Of course in that case you'd want to let ATC know tat you won't be flying the normal missed approach!


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