Departure Segments

[aslan1982]

Can someone explain what are departure segments and why we have them

and do they also apply on go arounds

Thanks

[Nubboy]

They are a convenient way of dividing the period from when the aircraft starts it's takeoff roll to levelling in the cruise. They will include getting airborne to a height to clear a mythical non existent obstacle (screen), inial climb to get clear of the ground, reducing from take off thrust (either full thrust/power or reduced), reconfiguring from take off flap setting to clean, climb at atc constraine speeds, free climb at econical speeds.

Yes, the go around will have similar divisions where these changes take place.

The whole issue is of course, performance. Different rules apply to different types of operation and aircraft.

Although absolutely vital in limiting situations, where it should have your complete utter and undivided attention to getting it right, most of the time it's regarded as being dull and boring, something that must be learned.:ok:

Hope this helps.

[galaxy flyer]

First Segment
Extends from lift off to gear up point. Thrust maintained at T/O thrust setting. From lift off until gear is retracted (end of first segment), the engine out climb gradient must be positive for a twin engined aeroplane and at least 0.5% for a four engined aeroplane.

Second Segment
Begins at gear up point and continues to level off height. During engine out second segment, the thrust is maintained at T/O thrust setting and speed = V2. Engine out climb capability at the start of the 2nd segment is 2.4% fora twin and 3% for a 4 engined aeroplane. This tends to be the most limiting of all the climb gradients.

Third Segment
Begins at initiation of level flight acceleration. This is level off height. Level off height is determined by:
- FAR min of 400ft = min level off height.
- Take off thrust time limits (5 mins in UK) = Max level off height.
- Obstacles.
- Extended V2 climb.
Climb gradient limits are 1.2% for 2 eng and 1.7% for 4 eng a/c.

Fourth Segment
This is the flaps up climb segment. Begins when flaps are up and aeroplane has accelerated to final climb speed. Thrust set to Max Continuous. Gradient limits are, 1.2% for 2 eng and 1.7% for 4 eng a/c. This segment is complete when all obstacles are cleared or the a/c has reached a min of 1500ft AAL.


Search is your friend (http://www.pprune.org/archive/index.php/t-95292.html)

Remember these are certification standards, real world obstacles might impose an extended second segment or level-off height to clear the terrain/obstacle.

GF

[aslan1982]

thanks for the help

ive read through that post and im now up to speed on the departure segments.

One thing that I cant seem to find out though is what segments apply on go around or do they have their own segments.

if i were to guess the go around segments would start at gear up so the second segment

Can you clarify this for me please

thanks

[john_tullamarine]

what segments apply on go around or do they have their own segments

"segments", per se, relate only to takeoff. The sensible pilot, or ops engineer, will do something similar to a takeoff analysis when scheduling a go round procedure from a runway with interesting terrain.

[supermoix]

Go around procedure have their own segments, check ICAO Doc 8168 chapter 6:

----------------------------------------------
6.1.7 Missed approach gradient

6.1.7.1 Normally procedures are based on a minimum missed approach climb gradient of 2.5 per cent. A gradient of 2 per cent may be used in the procedure construction if the necessary survey and safeguarding have been provided. With the approval of the appropriate authority, gradients of 3, 4 or 5 per cent may be used for aircraft whose climb performance permits an operational advantage to be thus obtained.

6.1.7.2 When a gradient other than 2.5 per cent is used, this is indicated on the instrument approach chart. In addition to the OCA/H for this gradient, the OCA/H applicable to the nominal gradient will also be shown.

6.1.7.3 Special conditions. It is emphasized that a missed approach procedure which is based on the nominal climb gradient of 2.5 per cent cannot be used by all aeroplanes when operating at or near maximum certificated gross mass and engine-out conditions. The operation of aeroplanes under these conditions needs special consideration at aerodromes which are critical due to obstacles on the missed approach area. This may result in a special procedure being established with a possible increase in the DA/H or MDA/H.

6.2 INITIAL PHASE
The initial phase begins at the MAPt and ends at the start of climb (SOC). This phase requires the concentrated attention of the pilot on establishing the climb and the changes in aeroplane configuration. It is assumed that guidance equipment is not extensively utilized during these manoeuvres, and for this reason, no turns are specified in this phase.

6.3 INTERMEDIATE PHASE

6.3.1 The intermediate phase begins at the SOC. The climb is continued, normally straight ahead. It extends to the first point where 50 m (164 ft) obstacle clearance is obtained and can be maintained.

6.3.2 The intermediate missed approach track may be changed by a maximum of 15° from that of the initial missed approach phase. During this phase, it is assumed that the aircraft begins track corrections.

6.4 FINAL PHASE

6.4.1 The final phase begins at the point where 50 m (164 ft) obstacle clearance is first obtained (for Category H procedures, 40 m (131 ft)) and can be maintained. It extends to the point where a new approach, holding or a return to en-route flight is initiated. Turns may be prescribed in this phase.
----------------------------------------------

There's more to it of course, company specific procedures and different regulations of countries which have differences with ICAO can have them, but this is the standard guideline for go-around and missed approach procedures.

Hope it helps.

[john_tullamarine]

Indeed .. however, that relates to the procedures designer when drafting the approach.

There is nothing imposed on the pilot/operator in a manner similar to the OEI takeoff analysis requirement and that is a deficiency in the system, I submit.

[supermoix]

Agreed John.

[Nubboy]

From a practical point of view, wouldn't that be overcomplicating things.

If you have the performance to make a takeoff from that runway, in the same prevailing conditions, at your current weight, then aren't you better placed in executing a go around from a missed approach. Even if you decide to reject the landing just before touchdown, you should surely be in a higher energy condition than having started from standstill at the threshold. I realise oddities like displaced thresholds mean this isn't always the case.

Expert comments please.

[john_tullamarine]

Not a simple Q & A and depends on a bunch of things.

(a) If terrain is benign then, probably, all is fine.

(b) If terrain is torrid, question becomes - can you track per the departure procedure after initiating the miss ? GPS helps a tad but, generally, a difficult exercise IMC.

(c) AEO, not too big an ask in most cases

(d) OEI, depends on where and when, and configuration changes required to get to the takeoff configuration for which your same weight hypothesis applies.

[aslan1982]

i suppose for a single engine go around seeing as though you only have flap 1 is that you initiate go around thrust - positive rate - gear up - climb at v2.

do you then, as with the departure segments on a single engine failure after v1,

level off at 400 feet wait for speed to reach flap retract speed, retract flap and continue your climb as per the missed approach instructions.??

[flyprototype]

nono, you don't level off at 400ft., too low!

below 400 feet, no ecam action.
at 400 ft, do your ecam action and let the plane climb.

when fire is stopped, level off...you proabably are above 1500ft. retract flaps, accelerate to green dot and continue your climb , then resume ecam action, (secure engine...)

[john_tullamarine]

do you then, as with the departure segments on a single engine failure after v1, level off at 400 feet wait for speed to reach flap retract speed, retract flap and continue your climb as per the missed approach instructions.??

I hope that your airline trains you better than your post suggests ...

If there is no terrain to consider (eg over water) most operators will have a standard delta height above the missed approach altitude/height at which one transitions to the cleanup. This may well vary according to whether you are AEO or OEI.

If there is terrain to consider, you need to have had someone run a sensible escape calculation .. otherwise, sooner or later, you will become a CFIT statistic ...

QRH etc., drills can wait until you sort out the intial terrain problems, I suggest .. no point doing a perfect securing of the engine as you fly into the mountain ..

[aslan1982]

Hi John

I dont work for an airline yet. Im preparing for an interview and one of the feedback questions is

What are the departure segments and do they apply on a go around two engined/one engined?

I understand the departure segments from take off with an engine failure after V1 but I couldn't find out anything on when you have taken off, had an engine failure after V1, followed the departure segments to ensure obstacle clearance (single engine) - come around for another approach and for some reason you had to go around single engine.

In my MCC training in an asymmetric go around, we applied go around thrust and at 1500 feet we lowered the nose a bit to pick up speed in order to retract the flaps and speed up to 210 knots.

That was basically the same for when we had an engine failure after V1.
We climbed at v2+15 pos rate gear up - 400 feet hdg select - 1500 feet was flap retract alt so lowered the nose an soo on.....

I had never heard about departure segments before, so now that I know about the ones on take off, I wanted to know if there was any specific ones for single engined go arounds

hope that makes sense

[john_tullamarine]

I dont work for an airline yet.

apologies for my needlessly harsh comments, then.

one of the feedback questions is What are the departure segments and do they apply on a go around two engined/one engined?

Short answer is "no" but you need to separate and address three considerations -

(a) procedures designers (the guys and gals who design instrument letdown procedures and draw the plates which we use in flight) are required to consider obstacle clear gradients and areas in the missed approach and, to this extent, one can talk about segments during the missed approach, or go-around but these have nothing to do with the takeoff segments. They are intended to provide for a reasonable terrain clearance but only for AEO missed approaches.

(b) if you mix a go-around with OEI, then you are on your own. Reputable operators will have developed specific procedures for difficult runways and these may well include the imposition of higher minima for a planned OEI approach .. what happens if you start AEO and then lose an engine below the higher minima ? .. tricky, and you need to have planned for this eventuality before committing to the approach. Depending on the terrain situation, it may move the decision making processes toward making that higher minima the general decision point - this certainly would be my approach to the problem.

(c) takeoff segments are built into the design and operating standards and are intended to address a presumed engine failure around V1

In my MCC training in an asymmetric go around, we applied go around thrust and at 1500 feet we lowered the nose a bit to pick up speed in order to retract the flaps and speed up to 210 knots.

That's fine for benign terrain runways .. but what was the consideration for a terrain critical runway ? Probably, I suggest, the MMC training addressed the basics with the expectation that the airline would, in due course, look to the details.

That was basically the same for when we had an engine failure after V1.
We climbed at v2+15 pos rate gear up - 400 feet hdg select - 1500 feet was flap retract alt so lowered the nose an soo on.....

Quite typical .. but the same caveat applies

I wanted to know if there was any specific ones for single engined go arounds

Short answer is "no" .. but you (and your operator) had better be thinking about what you are going to do during an OEI missed approach for a terrain critical runway ... or you might just end up dead .. sooner or later.

[galaxy flyer]

J_T

Probably, I suggest, the MMC training addressed the basics with the expectation that the airline would, in due course, look to the details.

John, you are an optimist. As many do, I suspect the MCC concept is yet another dumbing down of aviation.

GF

[john_tullamarine]

.. who am I to dispute such a view ?