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scandinavian13

A 777 Challenge - Part 2

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Back in September, I had a unique vantage point to watch a 777 crew make an interesting early morning short visual approach at IAD. Since it seemed like a fun challenge, I posted it here to give others an opportunity to try their own hand at flying it. For those of you who are unfamiliar, that post is here: http://forum.avsim.net/topic/450840-a-777-challenge/

 

 

 

The other day, in order to stave off a desire to go rent an airplane (which I'll finally be doing again this Saturday, thankfully), I decided to take the 777 for a trip across the Atlantic. In order to make it a little more interesting, I did the flight on VATSIM. As I was partially through my descent, I contacted London Control to guide me in.

 

Now, I have a feeling that the instructions I received were the "norm" for arrivals into LHR at that time of night, but it presented a unique challenge that I had to address through using different modes on the MCP somewhat late in the game. I was on the OCK STAR from BEDEK, with an instruction to cross BEDEK at FL140. After BEDEK and in a descent to about FL070, I was assigned a speed of 220. I was also assigned an instruction of "leave OCKham heading 070." Thereafter, I had a couple intermediate altitude assignments that were revised prior to having reached them (so I remained in FL CH uninterrupted), down to 3000. I was then assigned a speed of 180 and a heading of 360 immediately following it. Soon thereafter, I got a clearance to fly the ILS27L approach. This was followed by a re-stated speed restriction of 160 until 4 DME.

 

**For reference, the provided vectors and altitudes closely followed the charted ILS27L path transition off of OCK.**

 

So, here are the challenging bits to force you out of the VNAV/LNAV modes that so many are dependent on and use the MCP toolbox:

  • After BEDEK, I was given a descent and a reduction in speed. I simply used SPD INTV to modify the descent speed at this point. I also dropped Flap 1 as the UP speed was right around 220. I'm used to getting shoved (speed-wise) into LHR, so the bit of extra drag already available would help later in the arrival.
  • Upon receiving the "leave OCKham heading 070," I pre-selected the heading of 070 in the MCP heading window. As soon as I was over OCKham, I selected HDG SEL. At this point, I also selected FL CH because I was departing the LNAV path (with which the VNAV path is calculated) and rolled the altitude window down as appropriate.
  • Upon receiving the second speed reduction, I dialed it into the speed window, but also selected V/S mode to force myself into a slightly steeper descent than what FL CH would've used, though I sacrificed some of my deceleration rate by doing so. In order to recover some of my deceleration rate, I used some speed brake and flaps (on schedule).
  • At about this time, I was also assigned a heading of 360, which was handled with HDG SEL.
  • Soon thereafter, I was given my approach clearance (with a turn to about 290) with a re-stated speed restriction* of 160 until 4 DME. I handled this by turning the heading to 290, arming approach, rolling the speed back to 160, and jumping down to the CDU and entering EGLL and /4 on the first BRG/DIST line (different methods are available - as the ILS27L has a DME, what else could I have done?)
  • The rest was pretty standard, apart from the minor instability of having to drop the speed that late in the approach.

*In the United States, getting cleared for an approach implicitly cancels any prior speed restrictions. If you are to maintain a speed, the controller must re-state a speed restriction, as you saw here.

 

Again, this isn't an odd experience, but an interesting challenge I had the other night that I figured some of you would enjoy. Remember that there is no "right" answer here, and the MCP (along with some of the support functions of the FMS) is your toolbox to address the challenge at hand.

 

Here's my flight information, where you can pick up the date (for making a historical flight if you're using ASN - for instructions on how to do that, see Tutorial #1.5), the route, and so on: https://vatstats.net/flights/1527525 (the only part missing from the route string is the OCK2F STAR).

 

Extra info you might want, to help if you want to try it out using numbers close to mine:

ZFW was 441000

Release fuel was 137777 (IAD gate C4)

Fuel remaining over BEDEK was planned to be 34900 (might be helpful if you want to try departing an airport in Ireland to join the route at BEDEK and save a few hours.

(Units in pounds)

 

I'd enjoy hearing people's experience with it, or some videos. Good luck!

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Sometimes there is really really heavy traffic on the LonCtrls on vatsim. EGLL is always a challenge. I normally have the LAM3A and speedrestrictions by ATC is really putting you to test. Also in the NGX which as you know doesnt like to slowdown. I wonder why they do not use holdings there so often on vatsim.

 

speedbrake and flaps. Is this allowed on the 777.cant remember why it is not allowed on the 737.

 

Michael

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Is this allowed on the 777.cant remember why it is not allowed on the 737.

 

It's allowed on both. Discouraged at higher flap settings on both, mostly because of vibration and the fact that all that drag and spoiled lift isn't the best situation to be in. I was only using the speed brakes down to about Flap 5.

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Not that i want to hijack your challenge but could i have dreamed of something about slats not having antiice and because of that speedbrake would not be advisory in ice or below 10c? hmm sometimes i mix things

 

Not sure how those would be at all related, or relevant. Even if they were, it would only be in icing conditions obviously. I don't fly the thing, so take what I'm saying with a grain of salt, but it doesn't make much sense to me, which leads me to believe it's some random airline's SOP and not an actual regulatory/manufacturer requirement.

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I agree with Kyle, I really don't like using speed brakes and flaps. It usually means poor planning on my part and I question my pilotage.  If I do need to kill speed with flaps out then the gear go down and problem is solved.

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LHR is good fun -- for added challenge (and a bit more whizzing of the V/S wheel) see if you can achieve a CDA as well (in real life, your airline gets fined if you level off below 6000ft). Heathrow Director will tell you how many track miles you have to run to help you calculate this.

 

Incidentally, if you want to go round the houses a bit more, arriving from the east (BIG/LAM) takes you round the "S" turns when the 27s are active (though these are often truncated on VATSIM). Essentially, the Intermediate Director will bring a stream of aircraft off each stack -- about 070-ish degrees off OCK, whereas from BIG the basic plan is to initially aim directly at the OCK stack. Roughly abeam the airfield the two streams will be merged (entailing a ~160 degree right turn for the BIG traffic). Meanwhile, the same thing is happening north of the field -- with another Intermediate controller merging the LAM and BNN streams before aircraft from the two streams are handed off to Final Director for sequencing on to the ILS. It's quite something to behold!

 

 

 


I wonder why they do not use holdings there so often on vatsim.

 

Simply because there's rarely enough traffic to warrant it. The airspace is set up to land 35-40 aircraft an hour -- even on a busy night on VATSIM I've never seen anywhere near enough traffic to saturate the approach (events are a different matter -- but even then I find delays are generally fairly minimal).

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