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Single Engine turns before accel height???

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your_dreamguy

Well-known member
Joined
Jun 3, 2002
Posts
246
Just reviewing some single engine procedures. If you look at IAH ILS or LOC RWY 27, the initial missed instructions are," Climb to 520, then climbing left turn to 3000'...." The acceleration height for RWY 27 is 597. So, I have heard different instructors say different things about a single engine missed approach. Group 1 instructors say that when conducting a single engine missed, you wait until reaching acceleration height (597') before making the left turn. Group 2 instructors say that you can make the left turn at 520', even if single engine. Group 2 instructors argue the 520' would give you single engine obstacle clearance. If you go by group 2 instructors, what would be the point of having an acceleration height? Please tell me what you think.
 
Missed approaches have a 40 to 1 obstacle clearance zone, I believe that is lower than the SE climb gradients that we normally use.
 
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I may be wrong on this, but acceleration height has to do with a takeoff and climb gradient based on FAR PART 25 requirements.

On an instrument approach, you are climbing from a totally different point than you would be during a takeoff roll. Hence the difference. Also, aircraft configuration is not going to be the same between the two.

Sit down and read part 25 certification requirements, long read, but theres where some of the info is.
 
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FARs stipulate that the Minimum Flap Retraction Height will be 400 feet and the maximum is 1500 feet. Many operators use a standard 1000 or 1500 feet with some special airport exceptions.

Throughout the Second Segment, the landing gear is fully retracted and the speed maintained at V2.

The Third Segment is the "clean up" segment during which the aircraft is accelerated to the Flap Retraction Speed, at which point the flaps are retracted, climb speed established, and the power reduced to the climb or max continuous setting. It is usually flown level or in a shallow climb.

Once the flaps are up, speed is set, and climb or continuous power is established we enter the Final Segment.

I have always been taught that there should be no turns before 400 feet but there is no other restrictions on turns other than a limit of a maximum of 15 degrees of bank at V2 speed. There are many engine out procedures that call for a turn after 400 feet due to terrain or airspace restrictions.

IMHO
 
Following the published missed approach procedure while single engine (or go-around after the MAP) is not guaranteed to provide terrain clearance. At terrain sensitive airports, it may be worthwhile to look at the departure procedures for a given runway before commencing an approach.
 
There are times when a turn below 400 ft are authorized. We have an engine out procedure for takeoff at SLC that requires a turn at the end of the runway. We follow the normal missed approach though even if we are s/e. At RNO we must fly the same procedure for both engine out takeoff and missed approach. It is what the company terps.
 
Just reviewing some single engine procedures. If you look at IAH ILS or LOC RWY 27, the initial missed instructions are," Climb to 520, then climbing left turn to 3000'...." The acceleration height for RWY 27 is 597. So, I have heard different instructors say different things about a single engine missed approach. Group 1 instructors say that when conducting a single engine missed, you wait until reaching acceleration height (597') before making the left turn. Group 2 instructors say that you can make the left turn at 520', even if single engine. Group 2 instructors argue the 520' would give you single engine obstacle clearance. If you go by group 2 instructors, what would be the point of having an acceleration height? Please tell me what you think.

Acceleration Altitudes contextually pertain to a worst case scenario of Take-Off and engine failure at V1, thus the basis of your 4 segment climb as described accurately above by another poster, not the Missed approach procedure, while the clean up procedure for Part 121 aircraft is essentially the same.

A SE miss is totally different and the obstacle clearance prescribed for the 4 segment climb doesn't apply, unless preciptous terrain underlies the departure procedure, for which noted procedures are published for the said missed approach procedure.

Check the back of your Jepp airport 10-9 page for Obstacle/Instrument departure climb procedures/gradients. Your specific company Ops Specs may specify special use airports with specific climb/gradient instructions for your operation.

All that said, the MAP climb is I/A/W the published procedure.

T8
 
The only time I brief acceleration height is for takeoff, or for approach to a terrain critical airport for which there are special OEI procedures.

You must apply the OEI procedure if you go missed below MDA/DA (CAT I), or you pop a motor during a missed.

In any case you MUST turn at the point (altitude) specified at maximum bank for your speed and configuration. If you happen to be turning at the acceleration alt, that's okay.

In any case, it's not gonna be pretty.
 
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Isn't Acceleration height listed in the departure performance data issued with each release?

So how will an inbound crew know what the acceleration height is for that runway until they have landed and received their departure paperwork????

And for those that use electronic performance (OPS) such as JetBlue, again, the landing data will not provide an acceleration altitude.

The correct answer is to use the missed approach procedure as published. If the terrain is so severe that a special SE departure procedure must be used for a SE missed, the missed approach section of the Jepps will say so. Such is the case in SJO.
 

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