View Full Version : How To Keep on a Glide Slope In a 737
02-02-2006, 07:37 PM
I am learning to fly ILS using the VOR in smaller aircraft, but I can't find any information on how to use it in the 737 or the big birds. What am I supposed to be looking at to keep a proper glide slope to the runway in a heavy fog?
02-02-2006, 08:07 PM
The principles are exactly the same. The big difference is in approach speeds - the big birds come in much faster, and the descent rate is higher. Typical speeds are in the 155 - 135 mph range depending on weight; the heavier, the higher.
02-02-2006, 10:00 PM
In addition to the above response, I keep my approach at around 160kias for a -800. Just to put it in perspective, the approach speeds of the aircraft in question is around 160 as the average approach for a 172 (in real life) is around 60kias.
02-03-2006, 12:35 AM
160 is a little on the high side for a 737
02-03-2006, 12:50 AM
In addition to the speed difference, you are going to have different indicators on your HSI for the glideslope, unlike using needles on the smaller aircraft.
Remember, that some smaller airports are not equipped with the glideslope feature. Some will only have the 'localizer' which will give you the runway center indication.
02-03-2006, 02:16 AM
Roughly 5 times your approach speed should work
02-03-2006, 05:45 AM
roughly 125-132 KIAS and 700 fpm for a 737-400, that was according to the BA guy that taught me how to land one anyway. In the middle of the electronic AH should be two magenta lines, 1 horizontal and 1 vertical, these need to form a cross and hold that perfect cross all the way in. But apart from that as somebody said the principle is the same whether it's a Cessna 152 or an AN225.
02-03-2006, 08:17 AM
I have a little FS site with various bits of info. Take a look at the page Titled ILS and Autopilot it might give you a better picture of what the guys here are explaining.
Douglas B-707 Ret.
LINK click http://firstname.lastname@example.org/fs2002/Instruments/ILS_Tutoria_KIAD.html
02-07-2006, 11:54 PM
VREF+10 is what you should be at crossing 1000ft AGL
I can speculate for the 737 would be about 135
I know the learjets are about 125-130
02-08-2006, 08:43 AM
and... (I don't know if this applies to small planes):
you should control the rate of descent by engine power and the speed by nose up/down), in small adjustmenst, of course :D
Hope this helps
02-08-2006, 02:07 PM
I do it just the opposite, I pitch for whatever verticle speed keeps me on the glide, and use power to control airspeed.
02-11-2006, 12:36 AM
I was always taught that airspeed is controlled by the elevator and rates of ascent/ descent with the throttle.
Keep the speed constant, then if you are sinking or too low on the glideslope add power to reduce rate of descent. Pitching to keep you on the glideslope will throw off the speed, and that's why you need to add or reduce power to bring the speed back to where it should be.
Sure, you may be so far out of wack on the GS that you need to fudge with the pitch to get back on the GS, but you strive to keep from doing that, by keeping an eye on the indicators.
Keeping the speed constant you only worry about your power to keep on the GS. At least that's the way I was taught, and it seems to work very well.
02-11-2006, 02:38 AM
You're definately right about aoa controlling airspeed, I just find it easier to fly a precise ILS glideslope by pitching for vertical speed and using thrust to maintain Vref+10.
I guess it's the law of primacy too, that's how I was taught to fly an ILS years ago.
02-12-2006, 05:15 AM
Also remember to use the flaps correctly and don't try to land with tanks full of fuel, otherwise, you will be coming in too nose up.
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