EGNM Leeds Bradford Dopek 2W SID

[Christopher Low 5,352]

I set up the 737-600 NGX for a short flight from EGNM Leeds Bradford to EGNX East Midlands over the weekend. I selected the Dopek 2W SID as a departure, but the aircraft had trouble following it. When I selected LNAV above 400 feet, it made a rather too gentle turn to the left (completely ignoring the magenta line on the ND), so I switched LNAV off and then on again to try and get it to engage. However, the aircraft then made an incredibly steep turn to the left, and dived into the ground in what can only be classed as a "death spiral". I have never seen it do that before!

I had a look at the Dopek 2W SID, and it seems that this involves a slight (17 degree turn) to the right on a heading of 337 degrees.....but only for 0.2nm....before turning left to a heading of 307 degrees for 1.6nm. I am thinking that the aircraft was well past that 0.2nm by the time that LNAV engaged, and is maybe why it struggled to "lock on" to the correct trajectory.

I decided to delete that first 0.2nm @ 337 degrees section, so the first waypoint was 1.8nm @ 307 degrees. This worked better, but the aircraft turned inside the magenta line, and ended up having to level off before capturing it again and completing the left turn. For the record, the Dopek 2W SID departing runway 32 at Leeds Bradford involves an almost complete 180 degree turn to the left as a starter.

Has anyone else flown this SID out of EGNM Leeds Bradford in the 737 NGX? If so, did it behave OK?

 

EDIT: PLease note that this is using the release version of the Navigraph database.

[MadBilo 5]

PMDG 737NGX is not really good with tracking LNAV in this instance. Reason being is because it doesn't have ARINC 424-19 specification in full detail developed so this is the best it could do. 

So it will either do wrong turns or it will do a lot of S turns and can't track the magenta line properly, I have flown this SID out of EGNM many times, real life not like this but PMDG 737 its normal. 

Necmi Osman

[MarkJHarris 128]

Having been based there the last two years, we do LAMIX departures which are initially the same as the DOPEK. The -800 tends to turn left, then stop and go right for a moment before continuing left round the bend. We always use an Acceleration altitude of 1,700ft at EGNM. You are in the main left turn before beginning the cleanup phase. 

If you are accelerating or cleaning up sooner then the higher speed may be an issue? Also what power do you use? The -600 is going to climb like the proverbial unless you use an 18K derate with temperature too!

Iyi aksamlar Necmi hocam!

[Christopher Low 5,352]

I use the 18K derate with the 600, and I keep the speed under control these days (after learning to pitch up properly after take off)

[ubersu 78]

On 1/29/2018 at 4:51 PM, MarkJHarris said:

"Iyi aksamlar Necmi hocam!"

Necmi who?

David Jones

[MarkJHarris 128]

My Turkish is a bit rusty but I try...

[ubersu 78]

2 hours ago, MarkJHarris said:

My Turkish is a bit rusty but I try...

As is mine... You seem to have said, "Good evening, (salutation) Necmi". I just wondered who Necmi was/is? I just happened to notice because I lived there for several years long ago.

David Jones

[walfob 10]

On 29/01/2018 at 0:25 PM, Christopher Low said:

Has anyone else flown this SID out of EGNM Leeds Bradford in the 737 NGX? If so, did it behave OK?

I haven't flown this SID in the 737 NGX but I've just flown it in the 777 and the same thing happens. It won't follow the LAMIX departure from Runway 32. After take off it begins to follow the sharp turn left to follow the SID, but after tracking for about 90 degrees of the full 180 degree turn it then goes off at a tangent. To correct this I disengaged the AP and flew manually to complete the 180 degree turn to put the aircraft back on the magenta line and tried engaging the AP again. 

No luck. The aircraft wouldn't capture the flight path until I overwrote the FMC by flying direct to LAMIX. It then picked up the flight path and followed without any further problems.

Seems an unusual problem with this SID. 

     

[Christopher Low 5,352]

Thanks for the report, Bernard. That's an interesting observation.

[MadBilo 5]

On 06/02/2018 at 0:20 PM, ubersu said:

As is mine... You seem to have said, "Good evening, (salutation) Necmi". I just wondered who Necmi was/is? I just happened to notice because I lived there for several years long ago.

David Jones

He was speaking to me, 

 

Necmi Osman

[MarkJHarris 128]

Best me to it. The LAMIX is an interesting departure from Leeds, as is the Westerly from 32 through NELSA.. On departure the aircraft goes left, then hesitates or turns slightly right before continuing left. If you begin the cleanup at 1,700' you will accelerate and not be able to make the radius of turn onto the 138 radial towards Gamston. The aircraft tends to redraw the curve and intercept the radial about 4-5 miles after the turn rolls out. 

Fortunately I may never have to fly from that dump much longer!

[Christopher Low 5,352]

So even the real world departure has issues? Any reason why this has not been adjusted?

[MarkJHarris 128]

No idea. It's basically a coding issue I think. Nobody is too bothered as it's close in and most of us are still hand flying at that point. The COTML will slavishly follow the FD but the rare real pilots just ease the turn for a few seconds before continuing.

COTML

Children

Of

The

Magenta

Line.

The bane of my life.....