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Re: Can't seem to load approach

Postby Bobturner » Thu Nov 26, 2015 2:00 am

Since it worked on the ground but not in the air, this suggests an intermittant problem, the worst kind to trouble shoot.
I think the gNav mode requires the ARINC, so I would start there, looking, tugging, etc., at the two wires (A and B) connecting the gps ARINC out to the HXr ARINC in. Maybe GRT can guide you where else to look.
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Re: Can't seem to load approach

Postby gdtrfb58 » Sat Nov 28, 2015 2:02 pm

Looks like you are right about the ARINC. Yesterday, flew a couple of approaches, everything still grayed out on the EFIS. It was basically showing only whatever comes over the serial or analog inputs. The ARINC counters were dead. Today, powered up and the counters were ticking away and all the menus were lit up. I did give the whole unit a good thump in between (landing :oops: ). My guess is this is all about the 480 mounting tray. It is notorious for bad connections. I actually removed the 480 from the tray and re-seated it. All still good.
The other thing pointing to the tray is that when it wasn't working, neither ARINC was counting up.
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Re: Can't seem to load approach

Postby gdtrfb58 » Mon Nov 30, 2015 10:28 pm

Another update. Flew today. ARINC was communicating when I powered the system initially. I shut down the avionics and started up. When I powered the Avionics bus back up, no ARINC. I powered off the Avionics Master and the Master switch (powered down the GRT) when it all came back up, I had ARINC.
Tried to fly a GPS approach (07 @ N40). I was vectored to the final approach (after a PT). I had the approach in the 480 with the leg to the FAF selected as "Fly Leg" and active. I had the AP set up for GPS approach and on GNAV. When I was close to the course, I selected "Execute" on the GRT. I noticed it switched to ENAV. the AP flew through the Approach course, with no evidence that it was trying to turn onto the course. (The AP annunciator showed LNAV active and VNAV standby). I disconnected the AP and flew it. I was probably above the gluideslope, so I'm not surprised that it didn't capture the GS, but why not the lateral?

This I think is still my sequence, but I am wondering if the ARINC in the GRT is faulty. Any way to figure that out?
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Re: Can't seem to load approach

Postby Bobturner » Tue Dec 01, 2015 1:41 am

Easy stuff first. ARINC can be set to high speed or low speed. Be sure the GRT and 480 settings are the same.
Do you have any other equipment that outputs ARINC? If so see how the GRT reads that.
I don't understand the "vectored to final after a PT". I've never seen a PT that didn't end on the final approach course.
Switching to Enav after "execute" is normal. But I think I don't hit "execute" until established on final.
How did you get above tbe GS prior to the FAF? Normally you should intercept from below.
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Re: Can't seem to load approach

Postby gdtrfb58 » Tue Dec 01, 2015 11:27 am

I meant they vectored me to intercept after the PT.
They are all set to "low speed".
Only the 480 is connected to ARINC.
The PT is @ 2500 ft with a decent starting immediately after. They still had me @ 2500 ft when I intercepted that leg.

So, if you were flying an approach with a PT, would you press "Execute" upon arriving at the IAF (before the PT)? With my Century 2000 or STEC-50 (round gauges), it would fly the entire approach, including PT.
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Re: Can't seem to load approach

Postby gdtrfb58 » Tue Dec 01, 2015 11:15 pm

Well........Just got off the phone with Jeff @ GRT. Not yet confirmed, but it seems that there is a known issue with the HXr ARINC module in 28V systems. Apparently, there is a timing issue with power-up. If the sequence is a little "off" the ARINC won't power up. Once powered up, it is fine. Just waiting for confirmation and I will have to pull the unit and send it back to GRT for repair.
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Re: Can't seem to load approach

Postby Bobturner » Wed Dec 02, 2015 6:14 am

GRT_Jeff wrote:The ARM functions can only be used for the final part of the approach. They are designed to fly straight down to the runway and will not fly any turns or holds in the procedure. You must not EXECUTE the ARM mode until those turns have been completed and you are ready to intercept the localizer or runway.


I don't push "Execute" until I intercept the final approach course inbound. I think that's what GRT_Jeff says above.
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Re: Can't seem to load approach

Postby gdtrfb58 » Wed Dec 02, 2015 11:57 pm

I understand that now (That you have to be on the final/straight in leg before pressing execute).

It is confirmed that my HXr needs to be returned to GRT to swap out the power supply board.

The good news; I'm not crazy (or at least this isn't 1 of the symptoms) and there is a defect in the unit. In addition, GRT will repair it under warranty with their usual good service

The bad news; This is a known defect in the 28v power supply board and GRT really should be alerting those who have it.
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