Jump to content

Sign in to follow this  
craig_read

Low Approach Go Around Problems 747

Recommended Posts

Hi.. First of all I'd like to say I am a BIG fan of this aircraft.. and I am pretty sure that what is happening here is ME.. and not the simulation.. But I thought I would post a question because despite reading the manual I am having no joy..I am a member of VATSIM and I'm trying to get to grips with the basics of ATC for myself etc.. I'm already a very experienced PMDG 747-400 simmer.. So I'd say I do know what I'm doing with it.. So it may be a long post but I will step you through what I do.The environment is a takeoff and IFR loop around EGSS, as a practice.. I'm using Runway 23.. and the standard missed approach proceedure, which in this case is the BKY4R SID... 1 - Run through initial cockpit prep and performance prep.2 - Planning route in FMC, select EGSS as origin and dest.3 - Select R23.4 - In legs page set BKY as only waypoint at 273/3000 (I ignore the standard restriction to save time)5 - Set the BKY4R as the SID6 - Delete the last two waypoints of the SID as they go a bit far out my way.7 - FMC all happy.. route looks fine.. I set a fix at ISED at a 4 mile radius for the return.At this point all is rosey.. and at this point I have NOT set a arrival, as I'll probably get vectors.I take off.. climb.. turn right on the SID as usual.. continue climbing, once level and at 273knts I turn to 50 degrees on my downwind leg... after a little longer I set the FMC for ILS23 approach in the DEP page. I then set the peformance VREF for landing. 25/157.. Route comes up on the ND obviously not joined to BKY.. I do not bridge the discontinuity in the FMC (I have tried doing so and it makes no difference). At this point something strange happens on the ND, for some reason it draws hexagons around the airfield for the route???? I thought it's making some funny routing between two waypoints close together.. so I look and find RW23 and another waypoint VERY close to one another.. I find removing the waypoint (I can't remmeber the name) 0.2 miles from RW23 seems to sort that out.. Waypoints for landing are 3.. all along the runway track one at 4 miles the other two further out separated by 2 miles or so.. with RW23 at the end.. After RW23.. then the missed approch proceedure starts, just like the SID I used (at this airfield they are the same). At this point I change the missed approach slightly, by setting BKY as the FINAL waypoint on the missed approach proceedure at 273/3000.. It does however (and I stress this) make NO difference to the original tracking on the ND.. it just extends it somewhat to the BKY waypoint..Ok.. so what happens?.. Flying down the downwind leg.. everything is going fine.. I turn right onto 120 degrees.. heading to the runway track.. then finally turning to 200 degrees to capture the LOC.. LOC captured the aircraft starts to line up.. The active waypoint is now the one ahead on the approach track.. as I expected it be.. The aircraft is now in APP with 3 autopilots armed.. and descending with the ILS.. as it crosses the waypoint the next at 4DME is the active.. after that.. I'm close to RW23.. I wait till 400 feet and then hit TOGA... at this point what I expect happens.. the aircraft begins to ramp up and starts it's climb.. HOWEVER.. Shouldn't this thing start to speed up.. I mean I keep climbing at VREF! I actually at one point passed 2000 feet.. STILL at VREF..Now.. I disengage it as soon as I get a decent positive rate.. and use FLCH.. for 3000 and ramp up the speed to 250 to get a safe climb out of it.. as I pass 1000 feet.. I'm thinking.. I'll use VNAV and LNAV now.. Since I took the time to set them all up but it won't engage.. LNAV.. I get .. "NOT ON INTERCEPT HEADING"... now.. I realise I could be slightly off the track now.. but it's a matter of like.. 1 degree out.. or .1 of a mile at MOST!.. SURELY the FMC would be able to cope with that? I find I have a #### of a job using the heading bug to steer back to the track.. like 2 degrees to get LNAV to re-engage.. VNAV.. took some encouragement to engage too.. Now I may well be doing something fundamentally wrong here.. but I don't know what it is.. The only thing I can think of.. is the SID makes the track turn slightly after the threshold of the RW23.. and therefore when I pull up and continue on runway heading on TOGA, I am slightly to the LEFT of the track and not on an intercept heading to get to it.. so I turn 2 or 3 degrees right to capture it..I just find it hard to accept that in reality pilots have to go through all this on a missed approach.. I would have thought TOGA would set you on a runway heading and a climb up to your set miss ap alt.. and accellerate to your initial VNAV speed on the first waypoint of your missed approach proceedure? I would have thought VNAV would engage easily.. and LNAV would be intelligent enough to capture the missed approach proceedure..I am sure I am doing something wrong.. I would just like anyones comments on what I'm doing here..ThanksCraig


Craig Read, EGLL

Share this post


Link to post
Guest Loiosh

What was the speed and altitude set on the MCP when you initiated the GA? I've noticed that my plane will not climb past the MCP's altitude if it wasn't set to the proper runway height.

Share this post


Link to post

>What was the speed and altitude set on the MCP when you>initiated the GA? I've noticed that my plane will not climb>past the MCP's altitude if it wasn't set to the proper runway>height.Once APP was engaged.. I set the MCP to 3000 feet.. for the SID.. the speed was obviously for the approach speed.. HOWEVER.. after I initiated the go around with TOGA.. I could not change the speed.. at all.. I tried to change it.. but it would spring back to the approach speed.. I had to activate FLCH and then I could change it...


Craig Read, EGLL

Share this post


Link to post
Guest Loiosh

I had a similar issue as well. I noticed that it would not change until I had the gear and flaps raised. It reminded me a bit of some of the Control Laws for the A320.I don't know if that is what happened, but it is what it felt like.

Share this post


Link to post

I don't know about that.. how can you raise the flaps without accellerating through the flap speeds.. If I raise them at 155 knots.. she'll stall! Raising the gear made no difference.. I just get CONFIG GEAR! alerts.. Something isn't quite right here.. I am not sure if it's me.. or the simulation..


Craig Read, EGLL

Share this post


Link to post
Guest Loiosh

We'll probably need someone with more experience to answer this. I just remember raising my flaps. =) I probably am doing it incorrectly.

Share this post


Link to post

I appreciate your help mate.. I just want the answer :(


Craig Read, EGLL

Share this post


Link to post

Gidday Craig,The sim does do some strange things at times on the go around and I am not sure why. I have posted a bit on the PMDG wiki ops site regarding go- arounds. If the speed starts to deacy markedly then press the TO/GA switch again. This engages full GA thrust that helps with speed control. Try and engage LNAV passing thru 400 ft AGL and VNAV thru 1000 ft AGL. Check your FMA annunciations to verify you are getting what you select.If the speed starts looking all wrong as you get up towards the missed approach altitude then open up the MCP speed window and set in 200 kts (at least for the moment).I do find that some of the go-arounds do need a bit of "nursing" to help it through it.CheersSteve


Cheers

Steve Hall

Share this post


Link to post

Craig, I might have missed this but what do you do with the gear and flaps after to hit TOGA? You should set flaps to 20 and once positive rate of climb is seen, gear up. The aircraft is a bit of a pig trying to climb away in the landing config.As Cowpatz pointed out, he's written a good wee summary of the Go-around procedure on PMDG wiki. Check it out!EDIT: And let's not forget, if it isn't looking right, disconnect the autopilot and FLY THE PLANE rather than trying to recover from a tight spot using the autopilot. That's what you 'collect the paycheck' for after all... Amongst PMDG users there seems to be a an overall tendency to shy away from taking control from the AP when needed, but ultimately it's the best way in some circumstances.


Mark Adeane - NZWN
Boeing777_Banner_BetaTeam.jpg

Share this post


Link to post

Thanks for all the replies.. I have kinda found a way to do it.. This is how I approach it now..Approaching with APP engaged.. hit TOGA ONCE!... She starts to climb engines ramp up.. (at this point I CANNOT change the MCP speed setting it won't let me.. if I do.. it just springs back to the approach speed! Which I think is totally wrong)... SO.. what I do now is.. as soon as she's got a positive rate. 500fpm or more.. I hit FLCH.. and set the speed bug to 200.. I am able to change it then.... then as she climbs to missed approach alt I retract the flaps to 20.. then when I'll pull in the gear and retract flaps on schedule..I admit I use the A/P a bit too much.. I am however starting to fly all my approaches manually.. and their is a training lap you can do.. I saw on Aerowinx once.. I might replicate that and do it in the PMDG... But this TOGA does some funny stuff at times.. I think it might need looking into.. :)


Craig Read, EGLL

Share this post


Link to post

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now
Sign in to follow this  
  • Tom Allensworth,
    Founder of AVSIM Online


  • Flight Simulation's Premier Resource!

    AVSIM is a free service to the flight simulation community. AVSIM is staffed completely by volunteers and all funds donated to AVSIM go directly back to supporting the community. Your donation here helps to pay our bandwidth costs, emergency funding, and other general costs that crop up from time to time. Thank you for your support!

    Click here for more information and to see all donations year to date.
  • Donation Goals

    AVSIM's 2020 Fundraising Goal

    Donate to our annual general fundraising goal. This donation keeps our doors open and providing you service 24 x 7 x 365. Your donation here helps to pay our bandwidth costs, emergency funding, and other general costs that crop up from time to time. We reset this goal every new year for the following year's goal.


    2%
    $540.00 of $25,000.00 Donate Now
×
×
  • Create New...