Flying without AP - Descent

[Guest wolfiedqt]

Hi,i'm still struggling with the (final) descent flying the 737NGX manually (to high, to fast...).Could someone share his/her experiences/settings with me (speed, flaps, N1, trim etc.) ?Maybe an example final approach at ...Thanks

[davierosoft 13]

It could be of help doing that wit flight director and a full programming on the FMC, you will practice following the descend path, the various decelleration and correct angles to intercept ILS, Watch all the parameters, all the things, and you will learn how to do fully manually without FMC help.

[Fabo 213]

very general:aim for about 180kts and about 5flaps on localizer interceptaim for aboout 160kts and about 15 flaps on glideslope interceptthereafter final flaps and final speed via FMC landing init page.

[kjjj11223344 48]

Hi,i'm still struggling with the (final) descent flying the 737NGX manually (to high, to fast...).Could someone share his/her experiences/settings with me (speed, flaps, N1, trim etc.) ?Maybe an example final approach at ...Thanks

You can't slow down and descend at the same time with this bird, so you have to plan your approach. If you are going to be in a constant descent, then you might want to start adding flaps earlier as it will be harder to slow down if you don't.

[Guest]

Manual ? Take the altitude you are and subtract the altitude you have to land , the result has to be multiplied by 3 and to be sure ( terrain apart ) by 4.The result expressed in nm is the distance you have to start your descent.Remember to use air brakes every now and then if required.Keep in mind the big picture and " follow " it during the descent increasing and decreasing the descent according to your mind big picture.

[Nixon 30]

Just an idea why not firstly disconnect the autopilot and autothrottle when fully configured, remember the autothrottle settings etc and after doing that a few times start flying manually from further out.

[factory15 0]

had the same issue. my advice is leave the A/T on at first...will give you one less thing to worry about. Use the hud it will make it a bit easier and keep the plane trimmed. Save in a spot just before you capture loc or g/s and just keep practicing over and over again.

[rocketfs 2]

Hi,i'm still struggling with the (final) descent flying the 737NGX manually (to high, to fast...).Could someone share his/her experiences/settings with me (speed, flaps, N1, trim etc.) ?Maybe an example final approach at ...Thanks

Practice by manually flying different speeds, then making turns, then descend. Do this in all flaps/gear configurations. It will give you already at good feel of how much thrust you need. All this without landing.Then start practicing go arounds. Then touch and goes...Bert Van Bulck

[BorisTheSpider 0]

The suggestion to use the FMC and then follow the FD on either the HUD or the PFD is a good one - just disconnect the autopilot but leave LNAV and VNAV engaged so you're manually flying the FMCs commanded profile - just leave the A/T in at first so you get FMC SPEED annunciated. The TOD will appear on the ND in MAP mode. Be aware though that you will never be able to fly as efficient a descent as VNAV, doing this will give you an idea of the profile but in practise you need to fly a different kind of profile to do it manually given that you're not an FMC!!!For a more manual descent that requires a bit more thinking, use the PROG page in the CDU to get your remaining distance to the runway, then start a LVL change descent with 300kts set on the MCP at a distance in NM to go that is 3 times your altitude to lose in thousands of feet, and add on 20 miles for deceleration, maybe 30 at first so you don't make it too hard on yourself - losing energy in the 737 is not easy. For example, if you're at 36,000 feet and the airport is at sea level, you have 36000 feet to lose, 36 x 3 = 108 miles, add 30 for deceleration and for fudge factor so start your descent about 140 miles out. Initially set MCP ALT to 11,000.Notice that when you set speed on the MCP in LVL CHANGE you have speed protection, so the aircraft will accelerate as it descends since the margin to the high speed buffet will widen, you might start of at 240 kts IAS at 36000 feet and hit 300kts IAS at 25000 feet, but you can set 300 straight away at TOD and the autopilot will manage the speed. Of course, you can also hand fly this if you want, letting the speed hover around the bottom of the red blocks on the speed tape showing the high speed buffet boundary and pitching for speed as necessary, then pitch and trim for 300kts once you're there. In LVL CHG with the A/T in, the throttles will idle all the way down if the autopilot is flying, and if you're hand flying they will idle unless you pitch up to slow below the MCP speed set, then they'll kick in to hold that speed, resulting in more energy, resulting in starting over again probably! Set your MCP ALT to 11000 so you can decelerate at 11000 feet to 250kts before further descent to comply with the 250kts speed restriction below 10000 feet. A good slot to be in will be about 40NM out at 10,000 ft and 250kt IAS, or at least that's a workable starting point, and it's better to drag it in under power the first few times than blow it and end up hot and high. At least PMDG aren't going to sack you for wasting fuel, either way....Once you hit 250kts continue your descent to about 3000 ft above field elevation (LVL change again, or V/S if you want to keep the rate of descent lower, but that will use more track miles) at 250kts, then at 3000 AFE you want to slow to around 180kts as already mentioned. Fly level to decelerate - reckon on about 1 nautical mile per 10kts of speed to lose, so to go from 250kts to 180 will take maybe 7 miles. Get the flaps out on schedule, so you'll probably end up with flaps 5, 180 kts and at 3000 FT AFE you should be about 15 miles to run probably (3000 feet - 3 x 3 = 9nm, plus you need a bit more to get configured and sorted out at Vref +x). Once you've got some flap out things start getting more manageable.Establish on the localiser or inbound track, descend to the platform at 180kts and try and wind up at the FAF at about 160kts or maybe even a bit slower if you're light and Vref is low. Get the gear out, flaps 15 going to landing flap as you continue to decelerate. On the glidepath, for a normal 3 degreee path, you start with 55% N1 and work it out from there with small adjustments as necessary. Ideally, a stable approach is fully configured (landing flap, gear out, localiser and glideslope within 1/2 scale deflection, Vref+5 if using A/T or a little more if using manual throttle at this point, engines spooled up to "over the fence" thrust (about 55% N1), stable rate of descent, speedbrakes down and armed for landing) by 1000ft AFE. Then, bleed off the extra margin of speed to be at Vref as you come over the numbers, idle the throttles and flare. The correct Vref additive is 5kts with autothrottle since it is better than you! ;-) and when flying manual throttle it is half the steady headwind component plus the entire gust factor, unless that comes to more than Vref+20 in which case you use Vref+20 as a maximum. If still air, use Vref+5 as a minimum.Of course there are other ways to do it, but LVL change and perhaps using V/S lower down is pretty manageable and gives you plenty to do without becoming too much to handle at first in terms of hand flying combined with simultaneous mental gymnastics.If you want to comply with STAR speed restrictions and levels in a realistic way, using the VSD (vertical situation display, available by pressing the CTR button when in MAP mode) will give you good situational awareness vertically, the restrictions (programmed in the FMC) are shown and the current descent profile is shown projected from the aircraft symbol. If you're decelerating (with a new speed set in the MCP) the green dot on the projected vertical profile shows you where you'll hit your new speed if you keep things going they way they are at the moment, like the green arc on the lateral ND display does for altitudes.Don't be afraid to get the speedbrakes out and indeed the gear out early if necessary - you'd always rather be a little low on energy than a little high.