Garmin 530 issues after FW update

[BigBadLou]

Our local avionics shop performed a free upgrade of the firmware on our 530 because it was "for safety". We were stupid enough to agree to it. (you never ever allow upgrades unless something is broken)

Well, now we have a brand new problem. The 530 drives the HSI in the panel and while it shows proper localizer and GS position on an ILS approach, the lateral course deflection is off on an RNAV (LPV) approach. I believe we saw it only on the final approach segment. The screen on the 530 shows the CDI centered while we're on the rwy centerline but the HSI is deflected left about 1 dot. That makes it unsafe to fly, of course.

We will do some more testing in the air (in VMC) to get solid data and photographic evidence.

Has anybody else seen this problem after a recent "safe" FW update?
What steps did you undertake to correct this?

 

[Jesse Saint]

You may need to do a recalibration of the deviation, which is done in the 530 configuration pages. You will set the needle at 150 degrees and then push a button on the 530 and it will recalibrate. See if that makes a difference.

 

[Clip4]

Easy adjustment. Back to the shop.

 

[Jesse Saint]

Give me a call on Monday & I can walk you through the adjustment. Phone number is on my website.

 

[BigBadLou]

Thank you for the advice. I will have to try it on Monday when I'm going to the hangar.
Out of curiosity, is it normal that Garmin requires recalibration after a simple FW update? What about pilots who don't know that a "safe" upgrade can kill them in IMC?

 

[Jesse Saint]

I have never heard of it doing this, but that is the easy thing to check to verify that it somehow didn't lose calibration.

 

[xander75]

it happens all the time. I come from a sw/hw dev background and especially when the code base is large, you can't just assume everything will work the same. One computation result affects another and it propagates. Release notes only say so much and don't give full detail either. sw bugs tend to be localized fixed, there is little to very less end to end validation. (if you knew which companies I used to work for, you'd probably never use their services anymore or think 2 (000) times....)
the fact that many of us just accept apple upgrades like candy is unheard of in my view. people are swayed by "Scary words" like security update or in our line, safety updates.
my rule is, no need to upgrade (aside from IFR cert maps etc of course) unless something is off. If a SW upgrade is necessary perform a few test flights to ensure similar and same operation.