Mayday: seeking urgent help STEC 55 coupled 430W

A

asgcpa

En-Route
Joined
Jul 19, 2012
Messages
2,559
Location
Illinois
Display Name
Display name:
CPA
Checkride is in less than 48 hours. Went up with a friend to practice a full VOR including procedure turn and published hold. Things were great. Cleared direct to the VOR. On the 430 I selected and loaded the approach. Pressed nav nav for GPSS on the STEC 55x ap. Things going great. Magenta line on the radial showed up, procedure turn was in white, but I figured it would turn magenta on the turn. It didn't and the plane started to fly by. I had my heading set for the turn outbound so I switched to heading mode and flew until I intercepted the final inbound in VLOC. Why didn't GPS and autopilot fly the turn based in flight plan for approach? Why was it in suspend?

What did I do wrong?
 
Well can't really help as I fly behind a G1000, but it would seem the root cause was the fact you were in suspend. Did you happen to notice when the 430 entered suspend? Think back, did you do anything different this time than the previous times you flew this approach?
 
Which approach, where were you in relation to the initial approach fix, what was the intercept angle, etc, .What mode did you have everything in exactly? It's kind of hard to understand what the problem is.

You mention you loaded the approach -- did you ACTIVATE the approach?

Need to know:

1.) Where you were
2.) What your heading was
3.) How everything was set

For every leg of what you did for us to help.

The little details matter and unless I know what all the little details were not much I can do to help.
 
I was on the outbound leg of the full VOR approach. It didn't auto sequence into the procedure turn. It was the KENW VOR 15. FAF is Sumer intersection.

I was cleared direct to ENW VOR and cleared for full VOR 15. On 430 selected approach loaded and activated using ENW as iaf. Checked that all the waypoints, proc turn, and hold were loaded in FP. Hit nav 2x on STEC to get in GPSS. Altitude was set using altitude bug and vs alt on STEC.

Navigated to ENW, then turned on heading. Past Sumer I expected it to turn left to 294 for pt outbound it didn't happen. Flew by it. I'm trying to figure out what went wrong.
 
You have a Checkride coming up shortly, you should know these parameters. Ron Levy mentions a 430 course that PIC recommends as a prerequisite, might want to see if you can cram that in.
 
I can only offer suggestions for the GTN and STEC 60-2 that I own. It sounds like you were in VLOC mode. If you selected the correct transition and were flying to the PT, the CDI conversion from GPS to VLOC may have occurred without you noticing. This would explain why the magenta went away. GPSS would have been ignored since there was no valid GPS signal being sent.

The GTN series has an automatic switchover to VLOC when certain conditions are met. Is it possible that you met them and the switch occurred?


Sent from my iPad using Tapatalk
 
Last edited:
Are you sure it's a -W? The behavior is EXACTLY what you'd expect from a pre-WAAS 430.
 
Marauder said:
I can only offer suggestions for the GTN and STEC 60-2 that I own. It sounds like you were in VLOC mode. If you selected the correct transition and were flying to the PT, the CDI conversion from GPS to VLOC may have occurred without you noticing. This would explain why the magenta went away. GPSS would have been ignored since there was no valid GPS signal being sent.

The GTN series has an automatic switchover to VLOC when certain conditions are met. Is it possible that you met them and the switch occurred?


Sent from my iPad using Tapatalk
Click to expand...

flyingron said:
Are you sure it's a -W? The behavior is EXACTLY what you'd expect from a pre-WAAS 430.
Click to expand...
What these guys say.
 
What do you mean you navigated to ENW and "turned on heading". Do you mean you turned a switch to a "heading" setting? Do you mean you intercepted the outbound course? Was the outbound course displayed as a magenta line up to the point of the depicted white procedure turn?

FWIW you can do that procedure turn however you'd like provided you do it on the protected side. A DPE isn't going to ding you for that. If I were coming from the north for that approach I would just pass the ENW vor, do one turn around the depicted hold (because it just happens to be on the protected side), and come inbound on the approach.
 
y5ume5u9.jpg


I'm not sure what is going on with your approach. My process will be different but it the concept should be the same.

As an example, if I am leaving APPLR headed for the IAF ENW, I am in GPS mode with the approach loaded. When I activate the approach, I get the procedure turn associated with the approach.

nyve6aje.jpg


When I continue the approach, the overlay continues until I am inbound on the turn. At which time the GTN comes up with a message to convert the CDI to the appropriate Nav signal, VLOC in this case (disregard the LOI message, I think Garmin does this to play with my mind on the demo).

One thing that did pop up was this:

eqe6yveg.jpg


This happened after the message to switch to VLOC came up but before I switched it. Definitely still on the procedure turn and definitely in GPS mode.


Sent from my iPad using Tapatalk
 
Last edited:
There is no GPS overlay for that approach so your approach DB probably has no GPS data for the PT barb.

Did it show up as a barb on your 430W or as a half-oval PT diagram? If so, what did your waypoint sequencing show next? Mine would say something like PT or IAF hold IIRC. I flew one of these with the 750 recently but it had a hold at the IAF for course reversal rather than a PT barb.

I have a GTN 750 with the Stec 55 (no X) and my GPSS is done via an external converter. So I select GPS on the 750 then GPSS on the converter and HDG on the 55. I have to switch to VLOC and NAV on the inbound tho to make it track my HSI instead of GPSS or HDG.

No idea if this helps at all.
 
You won't believe this! I just had this exact issue happen last week. It was almost the exact same situation, flying a coupled approach on a 430W with an STEC55. It definitely was in GPS mode and it flew through the turn. I could replicate the problem over and over. It drove me nuts trying to figure out what the problem was.

In the end, I figured it out.

WHEW!
 
ssonixx said:
You won't believe this! I just had this exact issue happen last week. It was almost the exact same situation, flying a coupled approach on a 430W with an STEC55. It definitely was in GPS mode and it flew through the turn. I could replicate the problem over and over. It drove me nuts trying to figure out what the problem was.

In the end, I figured it out.

WHEW!
Click to expand...


You and the OP are killing me! What was the solution!


Sent from my iPad using Tapatalk
 
Marauder said:
You and the OP are killing me! What was the solution!


Sent from my iPad using Tapatalk
Click to expand...

Well, I guess my sarcasm writing apparently sucks. I wrote that completely to bait.

I thought the thread was a tease so tried to make a point of it. I want closure as well. ;)
 
Henning said:
You have a Checkride coming up shortly, you should know these parameters. Ron Levy mentions a 430 course that PIC recommends as a prerequisite, might want to see if you can cram that in.
Click to expand...
He'd also need the S-Tec 55x course, and you aren't doing even the 430/530 course no less also the autopilot course in 48 hours. Also, the 430/530 course I recommend doesn't include the WAAS upgrade -- you need additional training for that.

My suggestion is to postpone the ride until you can sit down with your instructor, learn how this is supposed to work, and then go fly at least three approaches using the full system until you are comfortable doing it. There's no way your instructor can sign you off for the ride as things stand now, anyway, since you are clearly not prepared to pass the practical test on several Tasks.
 
If it was an STEC55 and not an STEC55X, there is no native GPSS so you must select heading instead of nav mode, and then select GPSS on the GPSS/heading switch that's installed as part of the GPSS installation. Nav mode won't follow the GPSS heading information.
 
ssonixx said:
Well, I guess my sarcasm writing apparently sucks. I wrote that completely to bait.

I thought the thread was a tease so tried to make a point of it. I want closure as well. ;)
Click to expand...


I was hoping your post was sarcasm. Now what about that OP?


Sent from my iPad using Tapatalk
 
Lateral guidance on the 55X is a piece of cake. Unless you've punched up HDG+NAV it will agressively try to center the needle (NAV) or put you on the purple line (GPSS). Understanding what you have to do to get it to capture the GS is a bit trickier. I'm pretty sure I know, but periodically as the bars on my HSI are heading down from center, I just give up and push the RED button.
 
It was a simple solution. One interim instructor had me navigate to fix during direct enter enter after highlighting fix. This was after selecting approach and loading. I had been in training loading and activating at same time. Screw the direct to. I'm going back to the training stuff and it worked. I'm just a nervous wreck going over all this stuff.

It worked on 4 approaches including the published holds on missed.
 
Last edited:
Did you have problems when you loaded the approach with the fix (as opposed to vectors) and activated it?
 
ssonixx said:
Did you have problems when you loaded the approach with the fix (as opposed to vectors) and activated it?
Click to expand...

Sounds like he had selected vectors and not the IAF.

Regardless, learn how to activate a leg in the Flight Plan screen. Sometimes **** doesn't sequence like you want for one reason or another and when that happens few people seem to actually have any clue how to manually activate a leg which is what generally needs to be done.
 
It's still not clear to me what you did to correct it. But as long as you feel you know what is needed to do it right, that's all that matters.


Sent from my iPad using Tapatalk
 
jesse said:
Sounds like he had selected vectors and not the IAF.



Regardless, learn how to activate a leg in the Flight Plan screen. Sometimes **** doesn't sequence like you want for one reason or another and when that happens few people seem to actually have any clue how to manually activate a leg which is what generally needs to be done.
Click to expand...


Thanks, that makes sense.


Sent from my iPad using Tapatalk
 
asgcpa said:
It was a simple solution. One interim instructor had me navigate to fix during direct enter enter after highlighting fix. This was after selecting approach and loading. I had been in training loading and activating at same time. Screw the direct to. I'm going back to the training stuff and it worked. I'm just a nervous wreck going over all this stuff.

It worked on 4 approaches including the published holds on missed.
Click to expand...

You figured out a work around, good, however that is not a solution. In order to figure out a solution you have to understand what caused the problem first. What you have done is avoided the problem. Good enough for now, but stuff to keep working on in your mind until you figure out why it happened that way. You have to understand your equipment, it's part of being PIC, and knowing the boxes and why they do what when is very important in IFR flying, especially if you don't keep a cross ref system in your lap to revert to when the inevitable, "what's it doing now!?!" occasion arises.

Never let your ability to hand fly 2hrs in the crap then shoot an approach to minimums disintegrate, because you will need it if you fly in IMC much, autopilots fail regularly for a variety of reasons.
 
If you are on AOPA, or likely you can google him directly, you may want to do a day with Paul Sanchez, he can teach this stuff very well.
 
Henning said:
Never let your ability to hand fly 2hrs in the crap then shoot an approach to minimums disintegrate, because you will need it if you fly in IMC much, autopilots fail regularly for a variety of reasons.
Click to expand...

To that point, I came across a webpage many moons ago titled "How my Century Autopilot tried to kill me today"...

I got a good laugh from it -- yet understood what they were talking about. I treat mine with great suspicion, watch it like a hawk on the approach, and keep a finger on the disconnect button.
 
You must log in or register to reply here.
Back
Top