Stratus ESG did not squawk altitude yesterday

A

Aviator305

Pre-takeoff checklist
Joined
Apr 8, 2015
Messages
219
Display Name
Display name:
Juan
Just wondering if anyone has experience this, too.

Yesterday, I took off from KMCO, and the controller asked me to recycle my transponder. Sure enough, my transponder was on the ON mode but not squawking altitude. When I pressed the ALT button, it stayed on the ON mode. I then cycled the between STBY, GND, ON, and finally ALT buttons. Unfortunately, pressing ALT button did not produce the desired result with the unit staying in the ON mode. Long story short.. after turning the unit off and on and repeating the above process three or four times, ATC left me off the hook and I continued to leave bravo airspace. The unit self corrected and started squawking altitude spontaneously. Does anyone have idea what could’ve caused this, or if I could’ve done anything differently?

Thank you in advance for your thoughts
 
If it is getting no altitude, it may not let you go into Alt mode, but my memory says that getting no Alt will give you an error message. May be worth a call to Appareo to verify.
 
My older encoder seems to take 7-10 minutes to warm up and start. After five minutes you should get a warning on the E.S.G. which would have to press function to reset it. It has not happened yet but I could certainly see a situation in which I would takeoff before the encoder started working if I wasn’t paying attention.
 
Bacho said:
My older encoder seems to take 7-10 minutes to warm up and start. After five minutes you should get a warning on the E.S.G. which would have to press function to reset it. It has not happened yet but I could certainly see a situation in which I would takeoff before the encoder started working if I wasn’t paying attention.
Click to expand...

Hmmm... The confusing thing is that I saw the transponder squawking ALT on the ground before leaving the ramp. I only looked there before getting on the taxiway because the AFD for KMCO called for ALT at all times. This unit usually does not go into ALT until I'm airborne, so I was surprised to see ALT on the ground, and I was then doubly surprised when it wouldn't squawk ALT shortly after takeoff!
 
Aviator305 said:
Hmmm... The confusing thing is that I saw the transponder squawking ALT on the ground before leaving the ramp. I only looked there before getting on the taxiway because the AFD for KMCO called for ALT at all times. This unit usually does not go into ALT until I'm airborne, so I was surprised to see ALT on the ground, and I was then doubly surprised when it wouldn't squawk ALT shortly after takeoff!
Click to expand...
How does it decide if it should squawk ALT? By speed over ground? A large change in air pressure over a short period of time? GPS altitude vs. ground elevation at that position?

If it squawks ALT based on GPS (altitude or ground), could it possibly have been receiving bogus GPS data?
 
Cap'n Jack said:
How does it decide if it should squawk ALT? By speed over ground? A large change in air pressure over a short period of time? GPS altitude vs. ground elevation at that position?

If it squawks ALT based on GPS (altitude or ground), could it possibly have been receiving bogus GPS data?
Click to expand...

From the FAQ on Appareo’s website, going more than 15 knots on the ground for more than 10 seconds can cause it to go to ALT mode, but I really don’t think I did that yesterday. I wonder if what you posit represents another mechanism.
 
Aviator305 said:
From the FAQ on Appareo’s website, going more than 15 knots on the ground for more than 10 seconds can cause it to go to ALT mode, but I really don’t think I did that yesterday. I wonder if what you posit represents another mechanism.
Click to expand...
You may not have been going fast, but the GPS may have been getting bogus data that made it think you were going that fast. Once airborne, it still couldn't get good data so it didn't know your speed, turning off the ALT mode.

If you can get the track log, look for "spikes" just before departure indicating that it thought you were in other locations. Likewise, look for areas of no data when you know you were airborne. These may show as straight lines, but no data points in the line.
 
Cap'n Jack said:
How does it decide if it should squawk ALT? By speed over ground? A large change in air pressure over a short period of time? GPS altitude vs. ground elevation at that position?

If it squawks ALT based on GPS (altitude or ground), could it possibly have been receiving bogus GPS data?
Click to expand...
It squawks ALT based on information from the external ALTitude encoder, which is still required equipment.
I'm just finishing up the install of a Stratus ESG and my avionics guy strongly encouraged me to get a new one even though my old one never had issues. So I did.
 
I would hope if it was locking out ALT mode due to a lack of encoder data that it would show a reasonable error message for same and not just ignore commands.

The Garmin stuff does. It said exactly what the problem was in plain English on the screen when the cable fell off the encoder due to the little locking mechanism on the DB connector missing being engaged by a couple of millimeters.

Not finding the argument that it was missing data very compelling unless that thing has truly awful error annunciations.
 
I used the antique altitude encoder with the ESG. I have flown with it for probably a year and a half now and it has been flawless. For a plane with no panel mounted GPS to feed, it is a great solution. It gives me compliance, push button sqwauk entry, Pad IN and AHRS on the pad. Makes my little taildragger more useful for sightseeing and short trips.
 
aftCG said:
It squawks ALT based on information from the external ALTitude encoder, which is still required equipment.
I'm just finishing up the install of a Stratus ESG and my avionics guy strongly encouraged me to get a new one even though my old one never had issues. So I did.
Click to expand...
I understand the altitude comes from an altitude encoder. But the OP reported it doesn't transmit that data until the speed is greater than a certain value. The problem, as I understand it, is that the altitude data isn't being transmitted.

denverpilot said:
I would hope if it was locking out ALT mode due to a lack of encoder data that it would show a reasonable error message for same and not just ignore commands.

The Garmin stuff does. It said exactly what the problem was in plain English on the screen when the cable fell off the encoder due to the little locking mechanism on the DB connector missing being engaged by a couple of millimeters.

Not finding the argument that it was missing data very compelling unless that thing has truly awful error annunciations.
Click to expand...
I agree with you, and that's why I don't really believe my theory either. But the data thus far doesn't disprove it. That's why I suggested looking at a track, if possible, so see if it supports that hypothesis.
 
Are you able to pull up or see a pressure altitude reading on the transponder?
 
I don't know how, but at the time I was seeing the pressure altitude on the screen of my transponder.

Edit: I remember my irritation increasing as I saw the pressure altitude on the screen and the blasted device simply refusing to transmit it (until decided to do so on its own a few minutes later).
 
I just had a problem with my ESG today. PA checks out on the ground, but once I go thru 6,700 ft in the climb, it starts back down again. The strange thing is, I descended back down, the transponder slowly ticked back up to 6,700 and then started back down again normally. It’s like I’ve got a 6,700 ft max block on it. I was thinking gotta be a software issue. Leak or encoder wouldn’t make sense.
 
But will it still squawk dirty?
 
Velocity173 said:
I just had a problem with my ESG today. PA checks out on the ground, but once I go thru 6,700 ft in the climb, it starts back down again. The strange thing is, I descended back down, the transponder slowly ticked back up to 6,700 and then started back down again normally. It’s like I’ve got a 6,700 ft max block on it. I was thinking gotta be a software issue. Leak or encoder wouldn’t make sense.
Click to expand...

Any weirdness with other static system instruments at the same time?
 
denverpilot said:
Any weirdness with other static system instruments at the same time?
Click to expand...

Nope. Those indications were normal. They found some cracks in my static tube during the install but all of that was replaced and never gave any problems with the old transponder (GTX-330) anyway.

To me it’s gotta be either a problem with the encoder or a software issue with the transponder. Just seems weird that it’s reliable below 6,700, then it hits a brick wall and starts descending while I’m climbing.
 
Velocity173 said:
Nope. Those indications were normal. They found some cracks in my static tube during the install but all of that was replaced and never gave any problems with the old transponder (GTX-330) anyway.

To me it’s gotta be either a problem with the encoder or a software issue with the transponder. Just seems weird that it’s reliable below 6,700, then it hits a brick wall and starts descending while I’m climbing.
Click to expand...

Would have to look at the bit pattern and do the math — but is it an old binary encoded encoder, versus the newer serial data ones? A large jump in numbers would be easy with a significant bit rollover to a pin that’s not working or not making contact.
 
denverpilot said:
Would have to look at the bit pattern and do the math — but is it an old binary encoded encoder, versus the newer serial data ones? A large jump in numbers would be easy with a significant bit rollover to a pin that’s not working or not making contact.
Click to expand...
Sandia 5-35.
 
denverpilot said:
Don’t know that one. BCD encoding or a serial cable was just a thought.

Having a bit flipped in BCD with one of the wires broken or not connected would create wild resulting decimal numbers is all I was saying...
Click to expand...

Bit code is showing an over temp. I don’t buy it though. It’s maybe 50 degrees behind the panel. What’s strange is, if that “1” was one spot left, that means bad altitude input. I think that’s gotta be it. Gonna contact Stratus and see what they say.
810DA544-2EE9-442B-8F1E-B41CB8F6D498.jpeg
 
OP here
After my initial problem, I wrote Stratus and some nice fellow replied with basically a copy paste of their FAQ section which was not helpful.

I went on my first flight yesterday since my post. On takeoff, the tower asked my to recycle my transponder, but I reported that it was squawking altitude correctly (Flightradar24 suggests that it starting squawking ALT only after reaching about 700-800 feet, and that's about when I looked down to the transponder following the complaint from the tower). Everything was fine enroute, but when I got close to my destination getting to pattern altitude it went into GROUND mode by itself, and pressing the ALT button would do nothing. Turning the transponder off and on would have no effect either.

Before all of this started happening, the Stratus was very reliable, and the only thing that I can think of that may have disturbed the steady state is that the transponder was checked for the 2yr IFR certification. Is it possible that something is loose or not reconnected properly? I'm not sure what that test actually entails.

Thanks
 
Last edited:
Yesterday, I verified the abnormal behavior carefully. The unit was squawking altitude from startup to taxi. The unit changed to GND mode as soon as I became airborne. At about the time I reached pattern altitude, it switched to altitude. It switched to GND at times while flying racetracks over the runway. I then took it to the Appareo dealer on the field.

Conclusion: The fix was simple. I do not have a squat switch as some asked, but the thought was valid because somehow the corresponding setting on the Stratus was incorrect. After changing the setting to "off," the problem was fixed.

I do not know how the incorrect setting was programmed in there because this unit had been working well for the past 3 years. Maybe someone went into program mode during my last 2-yr IFR check and changed it inadvertently. At any rate, this is case closed.
 
You must log in or register to reply here.
Back
Top