Newby hand flying an LPV

Betmerick

Betmerick

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Betmerick
Hello,

I'm fairly new into my Instrument and I'm having some difficulty on keeping within my deflection limits. I have used my Aspen Evo to monitor my HSI for course and the diamond for the glideslope.

My instructor is wanting me to use both diamonds but for some reason I'm finding it harder to maintain both aspects especially with the winds.

Any suggestions?
 
Without flying with you, it is hard to tell, I am tempted to say you might be paying too much attention to the HSI and glideslope indicators. Instead you should be watching the descent rate and heading more, and use the HSI/GS only as verification.
 
Assuming you are proficient in attitude flying (maintaining a constant course and attitude), the key is making SMALL corrections to your reference heading.

Let's say you are flying an RNAV 35 approach:
  • You might slect a heading of 350 for an initial reference heading. Then HOLD that heading for a bit and monitor your course deviation.
  • If the diamond starts moving to the left, change your reference heading 5 degrees left to 345 (a 5 degree change is PLENTY). HOLD that heading and monitor for a bit.
  • If the diamond stays put and and doesn't get any worse, that is your new reference heading to hold course. Crank in another 5 degrees left to bring the CDI back to center, then go back to your reference heading to keep it there.
  • Any time the CDI starts getting a dot away from center, check that you are maintaining you reference heading, and if so, IMMEDIATELY halt CDI drift with a SMALL heading change until you find the new reference heading. Then add a LITTLE more correction to corral the CDI and then get back to the new reference heading to hold it tnere.
If you figure out the reference heading and stomp on deviations with SMALL, patient changes, you will be able to maintain course within one dot of center, with practice. None of this will work until you can consistently maintain heading and attitude. Don't chase the CDI. Choose a heading, HOLD it, and wait a bit, then reevaluate.
 
chemgeek said:
Assuming you are proficient in attitude flying (maintaining a constant course and attitude), the key is making SMALL corrections to your reference heading.

Let's say you are flying an RNAV 35 approach:
  • You might slect a heading of 350 for an initial reference heading. Then HOLD that heading for a bit and monitor your course deviation.
  • If the diamond starts moving to the left, change your reference heading 5 degrees left to 345 (a 5 degree change is PLENTY). HOLD that heading and monitor for a bit.
  • If the diamond stays put and and doesn't get any worse, that is your new reference heading to hold course. Crank in another 5 degrees left to bring the CDI back to center, then go back to your reference heading to keep it there.
  • Any time the CDI starts getting a dot away from center, check that you are maintaining you reference heading, and if so, IMMEDIATELY halt CDI drift with a SMALL heading change until you find the new reference heading. Then add a LITTLE more correction to corral the CDI and then get back to the new reference heading to hold it tnere.
If you figure out the reference heading and stomp on deviations with SMALL, patient changes, you will be able to maintain course within one dot of center, with practice. None of this will work until you can consistently maintain heading and attitude. Don't chase the CDI. Choose a heading, HOLD it, and wait a bit, then reevaluate.
Click to expand...
Same for pitch...pick an attitude and change that rather than chasing the glide slope up and down.
chemgeek said:
Yep, you could call it that. To really bend your mind with this method one needs to fly NDB approaches. Alas, there are few left these days even for practice.
Click to expand...
Good news is a lot of TAAs have the option to display an RMI needle, so you can practice with a VOR or GPS course. :D
 
Just want to clarify, when u say “both diamonds” you mean the one for glide slope and the other for localizer? Just want to distinguish between those 2 and the ground track diamond....
 
With a GPS approach, you're required to use the GPS as your primary source of navigation. As such, using the GPS screen - either in CDI mode or even in map/magenta line mode - is a very helpful part of your scan. Remember, it will load up what the true course of your approach is. One of the better ways to handle that is keeping on that true course as best you can and correcting accordingly. If you then confirm on the HSI on the Aspen that you're on one side or the other of the needle, correct. Also, even 5 degrees is too much. Correct 2 degrees. Correct so little that you can literally use your rudder to do the correction instead of going back and forth with roll.

In fact, there's a good chance that your partial panel approach on your checkride will be something like a GPS approach with the Aspen failed. Mine was a GPS approach with 2 G5s failed. I used the GPS screen to stay on course and flew it with almost no cross track. It was literally the best approach I flew on my checkride.
 
I'm a newbie IR student as well and this is what has helped me:

First, when you're on the final approach course (or even intermediate leg), try to only use the rudder for any small heading corrections. You'll be much harder pressed to over-correct just using the pedals for course correction and adjustments.

Second, I've been using the cross-track value on the GPS to help with all of my navigation for en route and for approaches. Realistically, it shows the same data as the needle, but it shows it in numerical format. My instructor has given me a goal to keep that value within .05nm (and that if I can accomplish that then the needles will never get close to too much deflection.

Here's the cool thing about cross-track: once the desired track and current track line up, you can bug/set your reference heading like @chemgeek mentioned. Then add a small correction of 2 degrees with the rudder (assuming XTK is .15nm or less) and watch the XTK get closer to 0.00nm. Once you get this dialed in on approach, you don't need to glance all the way over to the GPS anymore as part of your scan.

Basically the same thing as the CDI needle, but .03nm XTK means more to me at a glance than a slight drift of the needle. Yesterday morning was my first approach where I took off the goggles and was literally lined up directly with the runway with basically no lateral correction needed. It felt great.

Just keep at it- there's a reason it takes so many hours before you can do your check ride.
 
N1120A said:
In fact, there's a good chance that your partial panel approach on your checkride will be something like a GPS approach with the Aspen failed. Mine was a GPS approach with 2 G5s failed. I used the GPS screen to stay on course and flew it with almost no cross track. It was literally the best approach I flew on my checkride.
Click to expand...

What did you use for glide slope with both G5 failed? On our local GPS approach the last crossing altitude in the profile view is all about 5 miles from the runway.
 
N1120A said:
Mine was a GPS approach with 2 G5s failed
Click to expand...

I think these failure modes in the checkride is "just because i can" failures. what are the chances of 2 independent G5's failing? if you have a complete power failure, your radio goes and so does the electric TC. what does DPE's do when the aircraft has a G3X and a G5 and no round gauges at all?

some older GPS (480) has a HSI page on its own, i wish i was done with my check ride with a 480 ...
 
Here is what the instrument ACS says about "partial panel" (my emphasis added):

"One [approach] is expected to be flown with reference to backup or partial panel instrumentation or navigation display, depending on the aircraft’s instrument avionics configuration, representing the failure mode(s) most realistic for the equipment used."

When I train, I try to train on most possible failure scenarios at some point in the syllabus. And if they're doing well, I've been known to throw multiple failures just as a test of what they do and how they react and handle it. But for the checkride, the examiner is supposed to use a realistic failure scenario. I know an owner who has three Aspen panels and two G5's in his airplane. Failing them all simultaneously would not be a realistic scenario, especially since they all have battery backups.

It would be a stretch, but failing all of the Aspens (or both of the G5's), could be called a realistic scenario, as those units have at least something in common even if it's just programming. So, some previously unknown bug could conceivably take all the Aspens down at once. Or both of the G5's. But I wouldn't call it realistic to take them all down at the same time just to see how the pilot reacts on a checkride.

And the most realistic worst-case scenario for any glass in the cockpit is just a failure of the display itself. Meaning, the screen goes dark. That's a perfectly realistic scenario.
 
I have a G500, GTN 650 glass and an analog altimeter, airspeed, VSI and turn coordinator. For Partial Panel, the DPE failed the whole G500. Flew a dive and drive with the GTN CDI, distance and the altimeter. For some reason I found that much easier to fly than the G500.
 
WannFly said:
I think these failure modes in the checkride is "just because i can" failures. what are the chances of 2 independent G5's failing? if you have a complete power failure, your radio goes and so does the electric TC. what does DPE's do when the aircraft has a G3X and a G5 and no round gauges at all?

some older GPS (480) has a HSI page on its own, i wish i was done with my check ride with a 480 ...
Click to expand...

A complete power failure would not fail the G5s for 4+ hours ;-).

I laughed then the DPE said both. I said "you know you can't bust me on this with a dual failure" and he laughed.

The airplane had a 530W, so it was super easy. The approach actually did not have LPV mins (the airport has another LPV only RNAV, something you don't see much), but is easy enough to fly with stepdowns anyway.
 
Try to think more simply imo. Fly headings not intercepts. I use heading bug to set my heading then fly the edges of the bug for corrections. the glideslope should be the easy part with some power changes- again small. Big corrections =blowing through targets.
you can get a very rough idea of what descent rate you are going to need based on winds.

practice when the wind is really howling or goto a field where it’ll shift on short final to help keep you on your toes.
 
Glideslope management is a whole 'nother discussion. To avoid chasing the glideslope, it is helpful to learn how to "fly by the numbers." If you know the power setting and attitude to get a nominal 500 fpm descent at a desired airspeed, you've got a good start. (For my plane, 1800 rpm and 1 degree down is 90 knots and 500 fpm descent, pretty close for a typical ILS or LPV.) From there, it is small corrections. I prefer making temporary corrections with the elevator, and if corrections are persistently needed, with power. But the same "reference" numbers and small corrections apply in the vertical axis as well as the horizontal axis. First STOP the deviation, then FIX the deviation, then back to the reference setting to HOLD it. Once you get the hang of it, you can even "pre-guess" deviations from the basic "numbers" to account for non-standard glideslopes and headwinds or tailwinds.

The whole "reference" setting idea was a revelation during my IR training. It makes staying on track easy and formulaic, as long as your basic scan and control skills are good enough to fly a consistent heading and attitude.

If you are in your early training, I would think it makes more sense to learn technique with non precision approaches, where it's mostly managing the horizontal axis while holding a constant step down altitude. Precision approaches are juggling more balls at once.

Enjoy the challenge. Instrument flying is fun.
 
You could be over correcting. If the needle is getting better don’t rush it. Often the problem is people try to get back the center and then overshoot. It is ok to be off (with limits) as long as the needle is going the right direction. It getting better slowly is almost, maybe better than just holding it centered.

Brian
 
I had a conversation about this with a friend of mine in the plane yesterday. He's a very steady stick and rudder guy, but has a tendency to think a 5 degree correction is minor. I made the point that 1-2 degree corrections are the ones that keep you from shooting through.
 
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