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Old 24th Jun 2010, 18:16
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B737-300\400\500 questions

A)what is the right procedure for an ILS app?VOR LOC first then APP mode? or Straight APP mode?


B)
On ILS approach on the B737 classic simulator check , may I use the rudder for any deviation of the LOC scale ? or I have to use only aileron?If I do use rudder ,will me disqualify me on the PPC check?Thanks


Thank you
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Old 24th Jun 2010, 19:11
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Formally the coverage area is 25nm for the localizer and 10nm for the glideslope.
For sure you can receive and - in most cases - intercept the respective beams well outside that area, but the system is usually not designed for that (however there are lots of local excemptions at different airports).
To avoid false captures it is good practise to go first for VORLOC and once you are established on LOC and within 10nm to arm the glide.
If you are joining within 10nm it is usually OK to go directly for the APP mode, there might only be ATC issues - like in the UK, where you are first cleared for the localizer and once you reported established, you are cleared for the ILS.

Concerning the rudder: Do not touch it at all (just if you have to, for example in engine failure or to de-crab before landing).

good luck
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Old 24th Jun 2010, 21:05
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I'll give you an oposite reply,regarding rhe previous:

Do as the FCOM says, which is APP for the ILS. The airplane will not capture the GS first,as it says on the FCOM,also. After doing flight data monitoring for some years now, I can tell you that one of the most common cause for unstabilized approach is selecting LOC before APP - about 60% of tle flights the crew forgot to select APP and remained above GS (it is not teh normal procedure to select LOC first on the FCOM or our SOP,so it's not standard)

Regarding rudder- yes,you may use it. Monitor LOC deviation, and press easily on the rudder to stop deviation and return to localizer. In this way you'll readjust the crab, and make it easy to stay on loc.
Using roll only you'll get back on Loc, but if you don't change the crab angle you'll end up drifting again..
Use roll ,if deviation is already high.
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Old 24th Jun 2010, 21:12
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Thanks

Thanks for the answers ,
Never the less I always I have been using APP mode on ILS approach and , I have been using the rudder for small deviation on the ILS app since I was flying the C172, I was not so sure if all those where maneuver that can be considered disqualifying for an sim check on the B737 classic PPC
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Old 24th Jun 2010, 21:30
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I'm wondering how many will agree with using rudder. I thought of that as a crutch at best in a Cessna and I doubt it has any business in a swept-wing jet.

Good luck in your training.
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Old 24th Jun 2010, 23:09
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If you use the rudder to correct the loc deviation you will lose two (possibly pretty) friends, the crew standing in the rear galley really won't appreciate it.
In 12500 hrs on 737 I have never seen anyone using rudder except de-crab to land in xwind, and single -engine
(fortunately so far only in sim )
Think if you read the Boeing FCTM you will find this is the normal way to control the beast, leave the rudder alone, the yaw damper is taking care of it in normal ops.
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Old 24th Jun 2010, 23:41
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Do as the FCOM says, which is APP for the ILS. The airplane will not capture the GS first,as it says on the FCOM,also.
This is a Boeing Flight Control Computer option. The FCOM should state what applies to your aircraft.

Last edited by NSEU; 26th Jun 2010 at 00:49.
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Old 24th Jun 2010, 23:57
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On the Classic, Always arm LOC first until interception and only then ILS to avoid capture of the Glideslope before LOC-established. Standard procedure as written in the FCOM.
DO NOT touch the Rudder AT ALL during your ILS unless faced with an engine-failure or to de-crab in the flare.
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Old 25th Jun 2010, 13:05
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APP yes, rudder no.

As said previously, the whole VOR/LOC or APP thing is a matter of what is installed in the a/c. I've flown classics that had written "arm VOR/LOC" first in the FCOM (8-10 years old FCOM's) and as Alexban said, indeed, there are FCOM's that say "arm APP" for an ILS.
In my opinion, there is no prob to do either, as long as you properly monitor the approach, however, best thing to do is to stick with your company's procedures.
As for the rudder use during ILS, please forget it, it is wrong (as a piloting technique) even in a C-172, although I have to admit, it works.
I personally belive it's sort of a "cheat" in a small plane, it is something you should not do in a transport.
BUT: that does not mean you should have your feet on the floor during an ILS in the 737!
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Old 25th Jun 2010, 13:50
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FA10:
Formally the coverage area is 25nm for the localizer and 10nm for the glideslope.
In the U.S. it is 18 nm within 10 degrees, and 10 miles over 10 degrees to 35 degrees.

If a greater distance is needed, then frequency protection has to be assessed, and a flight inspection performed for the required greater distance (known as extended service volumne of "ESV") The glideslope is flight inspected to the P-FAF.

The localizer parameters are covered by the FAA in the U.S. Aeronautical Information Manual, Section 1-1-9 b. 5.
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Old 25th Jun 2010, 21:35
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A) It depends on the aircraft spec. In our fleet there are both versions one that will not capture GS until LOC capture and other that will. Our SOP is that instead of having to remember which one does and does not all flights are flown in LOC first then after LOC capture APP is selected. If you still want to use APP only on the classic be very aware that you could end up with an aircraft that may head you down a false GS that may not be attached to a LOC.

B) My first instructor on B737 said that the rudder on the B737 has two uses, engine failure and foot rests. Whilst this was somewhat glib it was to point out that the rudder on the B737 is very powerful and should seldom needed. If you used rudder to correct LOC deviations in my airline you would not pass the check ride.
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Old 26th Jun 2010, 00:48
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FCTM 737 CL 5.12

The GS may be captured before the localizer in some airplanes.
The GS may be captured from either above or below. To avoid unwanted GS capture, LOC may be selected intiially, followed by APP mode.
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Old 26th Jun 2010, 00:51
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Thanks, BumpyFlight
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Old 26th Jun 2010, 05:44
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I was thinking about rudder usage,and for a beginner I would recommend sticking with aileron.
I use rudder on ILS, but 'use' means ' pressing ' on it very smoothly at the first sign of localizer movement. It is a smooth movement, I doubt you'll be able to capture it , even if you keep your legs on the pedals.
But , in gusty winds, or with high localizer deviations, use only roll, and correct the crab to maintain the localizer.
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Old 26th Jun 2010, 06:59
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In the U.S. it is 18 nm within 10 degrees, and 10 miles over 10 degrees to 35 degrees.
Same for ICAO, 10nm G/S and as you say for the LOC.

If you used rudder to correct LOC deviations in my airline you would not pass the check ride.
I have never understood this technique either. It looks smoother but the passengers must sense the lateral acceleration where as banking with aileron to correct is usually imperceptible in the cabin unless you look out of the window. Anyway, what you find is that guys who do this only do on the line and not in the sim.
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Old 26th Jun 2010, 07:42
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If you used rudder to correct LOC deviations in my airline you would not pass the check ride.
And quite rightly so. Deliberately skidding any aircraft to make a heading change is atrocious lack of airmanship. As well as causing a roll in the direction you are pushing the rudder, it causes an uncomfortable sensation to those unfortunates down at the back and air sickness may result.
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