Hello all, this is my first post on AVSIM forums and I hope to be a valuable member and contributor here :DI have a question regarding the ILS approach capability on the PMDG 747-400. Prior to top of descent, I have selected my STAR, entered into the FMC and exec'd it, which goes through okay. I notice that on the legs page, the legs that will take me onto the glideslope all say 240/(altitude). How can I get the plane to slow down so that I can extend flaps in anticipation for landing? My autoland always goes fine, but I usually end up dumping full flap on finals, instead of extending them according to the flap extension bug on the IAS indicator Thanks in advance for your time :)

Are You Descending with VNAV Or Vert Speed? Usually You Need to Use the Speed Brakes To Slow The Aircraft Down... 10'000 Feet No More Than 250KIAS Downwind 230KIAS And Final 210KIAS Not Sure If Those Are Real World SOP But That What Radar Contact Uses

Hi,Make sure you selet the VRef speed in the FMC, you normally select the 30 flaps landing. The speed will depend on what your current landing weight is. If I remember correctly, maximum landing weight is 630,000 pounds. You probably show dashes in the Speed window. To control the speed, click on the Speed knob and it should indicate 240 knots, or whatever your current speed is. Now reduce your speed by adjusting the speed control knob. Lower the flaps when the green line indicates it on the Speed tape. You should be at your VRef speed + 5 knots at least by the time you intercept the glide slope. Also remember to arm the spoilers.Ken.

Yes best advice is to control the speed yourself. I tend to use LVL CHG and speed control instead of VNAV towards the end of the descent.

Yes best advice is to control the speed yourself. I tend to use LVL CHG and speed control instead of VNAV towards the end of the descent.

In real world ops LVL CHG is a very bad idea at low altitudes. LVL CHG uses speed as a pitch reference, you could find yourself in a low energy situation, select FLCH and the automatics will aggressively pitch you down to hit target speed, not what you want at low altitude. Best to use VNAV or V/S at low altitude.Regards

Thanks for the tip Rob

Thanks for the replies guys, very helpful.

Those radar contact speeds are way too high. For a radar circuit into any moderately busy airport (not talking just LHR/CDG/JFK here, but airports like EGBB or EGPF for example) more or less standard speeds are used which are 220kts downwind, 180kts base leg and 160kts on final to be held to the marker or 4DME.This is done for a number of reasons:1: It helps ATC when everyone is doing more or less the same thing, makes judging turns and gaps much easier2: Tower need the standard 160 on final to judge departure or crossing gaps3: Most company SOPs now dictate stable approach criteria which usually dictate slow and configured at a certain point on the approach4: Higher speeds mean higher workload for the flightcrew and even when traffic is nonexistant and you can assign free speed they tend to stick with the speed profiles listed above.Most aircraft can remain clean at landing weight at 220kts so flap usually only needs to be applied late downwind or on the turn to base for speed reduction.Certainly in my experience LVL CHG is used frequently in the terminal environment where speed is usually the overriding priority rather than descent rate. Under ATC assigned speed control VNAV is useless because it may command a speed different from that required.

Those radar contact speeds are way too high. For a radar circuit into any moderately busy airport (not talking just LHR/CDG/JFK here, but airports like EGBB or EGPF for example) more or less standard speeds are used which are 220kts downwind, 180kts base leg and 160kts on final to be held to the marker or 4DME.This is done for a number of reasons:1: It helps ATC when everyone is doing more or less the same thing, makes judging turns and gaps much easier2: Tower need the standard 160 on final to judge departure or crossing gaps3: Most company SOPs now dictate stable approach criteria which usually dictate slow and configured at a certain point on the approach4: Higher speeds mean higher workload for the flightcrew and even when traffic is nonexistant and you can assign free speed they tend to stick with the speed profiles listed above.Most aircraft can remain clean at landing weight at 220kts so flap usually only needs to be applied late downwind or on the turn to base for speed reduction.Certainly in my experience LVL CHG is used frequently in the terminal environment where speed is usually the overriding priority rather than descent rate. Under ATC assigned speed control VNAV is useless because it may command a speed different from that required.

Your Correct I Did Not Word That Right.... I Meant Radar Contact Does Not Want You Going Any Faster Than Those Speeds You Speed Is Up Too You As Long As You Dont Exceed Those Speeds

Thanks for the replies guys, very helpful.

I Never use VNAV Or LVL Change On Decent But I Do For My Climb Out And Cruise.....I Do Use The Speed In the VNAV Decent and I Always Or 95% Of The Time Use Vert Speed For Decent

I think you find RC only allows 210max on the intercept leg (base or straight in) and then you follow the flaps adjusting schedule for the length of final. Shortly before the outer marker(or seven miles out from the threshold) you should be in your landing configuration with landing flaps and starting to extend gear decreasing to touchdown speed in a stable approach..Unless restricted in the landing procedure VNAV speeds will not be published for final as that is an aircraft specific schedule that can vary with location as implemented by the crew. Maximum speeds might be in the procedure. Part of this is the winds present (direction and speed) to meet landing structure strain and maneuverability.For example in some situations you might touch down at higher roll-out speed if you are allowed to use the runway to get closer to your parking area by delaying runway exit and reduce therefore the amount of taxi fuel.Speed brakes would not normally be used once in the traffic pattern. Flaps and gear extension on final should provide enough drag.

Are You Descending with VNAV Or Vert Speed? Usually You Need to Use the Speed Brakes To Slow The Aircraft Down... 10'000 Feet No More Than 250KIAS Downwind 230KIAS And Final 210KIAS Not Sure If Those Are Real World SOP But That What Radar Contact Uses

LVL CHG on climbing engages N1 engine power and on descending engages idle power. At low altitudes AGL idle power is not used because of spool-up delay if you need to suddenly climb as in a go-around. Heavy aircraft are flown onto the runway with swift power reduction in the flare at 50 feet above the surface. Bringing the nose up will slow the aircraft with the additional drag.

The approach is considered "stable" when:* Aircraft is in landing config* Aircraft is at final approach speed* Aircraft is on the approach path (either VASI or within 1 dot on the ILS)* Thrust is set for the aircraft configuration (i.e. not chasing speed or at idle or full power, but about where it should be to hold approach speed)* Only small control inputs are required to maintain the flight path (again no large inputs because you are off-path)Instrument approach should be stable by 1000 ft RAVisual approach should be stable 500 ft RAVisual circuit/circle to land should be stable at 300 ft RA and wings level in landing config (e.g. you could do a low and close-in turn)Best regards,Robin.

I think you find RC only allows 210max on the intercept leg (base or straight in) and then you follow the flaps adjusting schedule for the length of final. Shortly before the outer marker(or seven miles out from the threshold) you should be in your landing configuration with landing flaps and starting to extend gear decreasing to touchdown speed in a stable approach..

 

Unless restricted in the landing procedure VNAV speeds will not be published for final as that is an aircraft specific schedule that can vary with location as implemented by the crew. Maximum speeds might be in the procedure. Part of this is the winds present (direction and speed) to meet landing structure strain and maneuverability.

 

For example in some situations you might touch down at higher roll-out speed if you are allowed to use the runway to get closer to your parking area by delaying runway exit and reduce therefore the amount of taxi fuel.

 

Speed brakes would not normally be used once in the traffic pattern. Flaps and gear extension on final should provide enough drag.

Maybe I Was A Bit Confusing :Worried: I Meant To Put When Given A Certain Altitude Like When Decending The 11,000 for 7,000 I Use the Speed Brakes Too Slow To 250Knots I Don't Use Them When My Flaps Are Out Anyways Back To Flying :good:

Certain airlines to minimize fuel burn dictate a policy of avoiding speed brakes by planning TOD accordingly. (RC uses the crossing restriction altitude to calculate TOD, not the destination altitude as used by the FMC hence the difference.) Usually the FMC will recommend speeds for the descent but the TOD is calculated for a constant descent at low power excluding any crossing restriction so it can be a bit off unless you put that hard altitude in at a point about 40 nm out from destination. The only time I usually need to deploy spoilers is when staying high enough for high terrain obstacles and then need to swiftly descend. If terrain is not an issue I may request a lower altitude further out.

 

In the PMDG 737s I put the speed restrictions for altitude (transition altitudes) into the performance page (I think) for destination.

 

RC uses 11,000 or 12,000 feet (FL120 or FL110) about 40 nm out from destination. In the Boeing Smith's type FMC I place a 40 nm range ring out from destination by entering on the FIX page the ICAO of the destination airport and the /40 for the PB entry and EXE it. I then use the descent arcs on the ND controlling v/s to insure I'm at or below the crossing restriction. I use the FMC speeds as guidance along with STAR charts to insure i don't stray into granite if in rough terrain.

 

By anticipating ATC commands you can plan ahead to avoid steep descents.