Auto pilot

[jrpilot]

          Hello


              I have a question on when you intercept the glideslope for a landing and you are using auto pilot.
 
  Should I turn on the NAVIGATION HOLD switch in autopilot or keep the HEADING HOLD switch on.  I've tried them both but auto pilot does not do anything when I have NAVIGATION HOLD on any help would be fantastic

                      Thank you

[Nexus]

Boeing recommends pilots to intercept the localizer before the glideslope becomes active or "alive". And that is not just a

[OTTOL]

Boeing recommends pilots to intercept the localizer before the glideslope becomes active or "alive". And that is not just a  company recommendation, it's kind of a general rule of thumb in aviation

 


The only time you WOULD fly through the localizer, is when ATC instructs you to do so.

As far as answering the question. Make sure you have De-selected the GPS, above all else. That is make sure you're not trying to shoot an ILS with the HSI "slaved" to the GPS. With the GPS still selected, you will still have glideslope, but a course indication that is nowhere near the precision required for an ILS approach! Nexus has the right Idea, but I think it's incomplete. You can use the heading bug to line up on the localizer,when it comes "alive", but when your stabilized, select APPCH(if the applicable GPS has this function), or NAV, as it centers, and at the same time select GS. Again the latter is for an autopilot that doesn't have an APPCH function.

[Nexus]

OTTOL, screw ATC, we both know the FS2002 ATC has a nice habit of giving you tight turns on finals. No time to be established at all really,

[OTTOL]

The sim does do some weird stuff on ocassion when you select the APPCH function on the autopilot. One thing to take into account though is that a flight director(which the AP is slaved to) is not merely an indication instrument. It has a computer that will account for a crosswind. The downside to this is that the AC might do a little swerving before it becomes stabilized. If the factors(intercept angle, wind, approach speed)are too extreme, it will have a hell of a time trying to "figure it out".   As far as his question.........This is the way that I read it.

Should I turn on the NAVIGATION HOLD switch in autopilot or keep the HEADING HOLD switch on.  I've tried them both but auto pilot does not do anything when I have NAVIGATION HOLD on any help would be fantastic  

 With autpilot ON, which button do I push?
The answer is A.................and B. You can select APPCH, which should CAPTURE the localizer and glideslope, or slowly turn the heading bug(with the AP selected to HEADING)and then  when everything is centered, select APPCH or NAV(NAV if it's an early AP, w/o an APPCH function). If you use the approach capture function, as stated earlier, make sure the dynamic factors are not too extreme, and make sure the GPS/NAV switch is selected to NAV.

[Nexus]

Oh, the TriStar comparison is from real life, not drawn from the sim. Overall, the TriStar has (according to pilots) the best AP's of them all. Smooth, reliable and not over-complicated. For instance, the AP on a L-1011 outmatches its B737NG counterpart when comming to pitch and roll commands. On Autoland, the aircraft even lowers the nosewheel by itself, impressive when considering how old the technology on the Tristar is.

Back to the Sim. I think that the AP..and especially the APP mode is very shaky. For me it's enough to be offset maybe 1-2 degrees from the runway's front course, and the AP will go nuts when engaging the approach hold. No thanks, but I rather trust my own instrument skills than trusting the default autopilot. This is also a reason why I support paware: They always comes with a re-written and enhanced AP..where the Automatic Flight System=AFDS(FCC+MCP)+ A/T logic of real aircrafts are copied. Maybe not 100% accurate, but the flights are much smoother. How much would it take Microsoft to buy that programmer code?  I can pinch in with a dollar or 2

[OTTOL]

I'm referring to REAL A/C, as well. In regards to the Flt Dir. In real life, or the sim, you have to allow the autopilot to "chase" the ILS, until it becomes established. This is the period where the Flt Dir computer is "figuring out" the correction needed. What I'm trying to say, is that for some reason, the sim sometimes will nosedive, and NEVER capture the glideslope. When airplanes do this in real life, we get the "RED BOOK" out, and call avionics.  :)   Jr, if you ARE reading this book we're writing, and aren't able to make sense of it, I suggest you list a default A/C and an approach that you like, and we'll help you with any SPECIFIC questions.

[Nexus]

Chasing needles is not one of my turn on's.
Only reminds me of my early days as a sim pilot with poorly planned and executed approaches.  :(

Anyways, Jrpilot sent me a PM and the aircraft he uses is the 777. I sincerely hope this is okay with Jrpilot that I share the private message he wrote. No question is ever stupid or dumb, and I can assure you that there are others reading this who will benefit from this

"Hello,
   Thank you for answering my question.

I have heard people telling me to put the APPRAOCH (APR) on but were do I find this at on the Boeing 777 for example. Do I put the ILS frequecies in the radio stakes then hit this APR button.
 Any help would be great.

Thank you "

The approach hold is a very handy function inplemented in the sim. The autopilot will follow the ILS signal and establish you on a nice glidepath and at the same time keeping the aircraft aligned with the runway. But as OTTOL already stated, the autopilot sometmes goes bananas and completely ruins the approach by wiggeling to left and right and not follow the glidepath at all. That's a major drag I tell you  :(

But enough of that, lets get to how you activate it:)
Let's say you're cleared to land at runway 26 by ATC. The first thing you would do is to dial in the correct ILS frequency in your NAV1 radio. The chances are pretty big that ATC will have you to make a tight procedure turn (final turn before runway alignement), so it's a plus if you plan your approach one step ahead. Altitude is important, ATC will usually tell you to be at 2100-2300ft when you will capture the glideslope

Anyway,You should  have the localiser (the magenta diamond which moves from left to right) at the center position on your PFD-screen BEFORE the glideslope (magenta diamond which moves up and down) becomes active. Active means when the diamond turns from just magenta outlines to a solid magenta color.
So maintain around 2100 feet and slowly watch the glideslope needle move downwards on you display screen.  When the diamond is 1 dot, or less above  the middle you can activate the APP function which is located between the speed and Heading boxes on the glareshield panel. The autopilot must be turned on, and I recommend you to use the autothrottle to maintain your speed. Oh, I almost forgot, you should be configured for finals before activating the APP mode. By this means landing flap setting (25 or 30 for the 777), landing gear down and a good pitch trim setting. This will decrease the chances for an autopilot approach mayhem  ;D

I hope I got something straightened out for you. English is not my mother tongue, so I hope you atleast understood my grammar  :)

Good luck!

[OTTOL]

There are no stupid questions, only stupid people asking questions!  Just kidding!  You are absolutely right, as long as the question is answered, the mission is accomplished. That's the ultimate objective of most of the Forums.
To display it so that others can learn as well, is a great idea. I have been flying planes for 22years, and know quite a bit about most of the intricacies of all aspects of the business, but my computer knowledge is, sadly, lacking. That's how I ended up at Simviation in the first place. I don't hesitate to ask a question(computer related), no matter HOW obvious I think that it may be to other members.