Next Invention:
Add 164Cd’s auto-pilot to the ‘fried’ (for real) bin over the weekend!
While on a 15 mile final (just left IMC) the smell overtook the cabin (like a pax bad gas!). Unable to identify cause all the gauges looked fine… I was IFR training with my CFI who thought the problem was outside. Hell, we would have had to been going thru Arizona’s wildfires for that kind of smell to hit so quickly.
Wiithin 30 seconds or so of the odor…I said goodbye to Approach, hit the Avionics switch, squawked 7600, handed the fire extinguisher to my CFI (just in case) and finished the landing (squeeked it BTW). Once the switch was cut off, the burning smell seemed to disipate very quickly.
After removing the glareshield on the ground, I turned on the master and the avionics. Smoke poured out of the rear of the Stec 30. The stream was like that of 2 burning cigs in an ash tray. Finally…the ‘roll trim’ breaker POPPED! No such luck in the air though…I am afraid the A/P would have caught fire before its breaker popped because it NEVER did on the ground. I should have let it burn just to see if it ever would.
Lessons learned:
Before ‘flames’ comes first smell then smoke.
The glaresheild needs to be able to quickly release. Peroid! (I would have yanked it off if I thought really necassary but unnecassary with a quick release latch)…then you could identify the area generating the problem and ‘pull the breakers in THAT area’… REGAIN the rest of the stack, COMM and safley land at ‘NRST’. Additioinally, I am placing a 4 X 6" mirror (with a handle in the plane to see behind the stack once the sheild is removed).
If I had this in real IMC, it would have taken about 20 seconds (max) once I ‘got the smell’ to remove the sheild… identify the problem ‘before’ I had to shut down ‘all’ the avionics. Bet you could ‘safely’ restore your avionics within 2 minutes…before you could say procedure turn!
I’ll post my solution soon because allen wrenches and screws ain’t gonna cut it next time the A/P or anything else begins to fry!
PS…on more than one occasion, I thought how could i get the fire extinguisher to ‘extinguish’ and area i most likely couldn’t get to as designed.
take care
I sympathize with your problem … felt the same way when mine went south (I was in cruise, solid IMC, at 9000 ft). That smell of fried semiconductor really generates a whopper of a pucker-factor (anal velcro if you prefer) when you can’t see the ground and you know its going to be a while before you can get there, too! Luckily, my roll trim breaker popped relatively soon after the A/P fried, so I knew to pull the A/P breaker too, and the smell went away fast.
Anybody know how many total SR20 A/P and roll trim servo combo deaths this makes?
Good to hear everything is okay. Were you using the autopilot at the time this happened (was the autopilot engaged?) You won’t need your autopilot for the checkride, but it is a great idea to learn to use it during instrument flight. That’s something your could do after you get that instrument ticket.
Just a comment. You said you hit the avionics switch first. I believe the POH indicates that you should hit the Bat-Alt master off first. In this situation you didn’t know the cause of the smoke/fire. Had it not been avionics-related, you would have continued to take on more smoke.
If you were in IMC, then you’d be forced to isolate the fault. Make sure to turn off the avionics master as well as all of the individual units and selectively turning each unit on (in order of necessity) one at a time waiting for the smell to return after each one. Sounds simple, huh? Not an easy task in IMC (add turbulence/icing possibilities and you become saturated very quickly).
It is interesting to see that the emergency checklist doesn’t say anything about turning off each individual unit before turning the avionics master back on. This is based off of the POH from the CD website.
Thanks for sharing your experience. It helps to hear these kinds of stories.
not sure how many Bill, but Cirrus told me 12 a/p’s and motors were on order and it likely be 2-3 weeks to obtain my parts. It hurts more since I am in the middle of my IFR training, a PIC pilot is coming July 24th to finish me up. Hope it is in by then. Would hate to take the check-ride without the A/P.
TC,
Would hate to take the check-ride without the A/P.
Don’t worry too much about it; I doubt the DE would let you use the A/P much anyway - at least mine didn’t when I had my IFR checkride ('course, that was in a 172, not an SR20!).
Would hate to take the check-ride without the A/P.
Hope you are that lucky! To have an examiner who would ALLOW you to do a check ride with the autopilot!!!
Dunno what FAA examiners think about autopilots, but my IFR check-ride prep included cautions that use of an autopilot is not part of the practical test standards so they don’t get used! Any my checkride was in an SR22.
Can you run your turn coordinator without the autopilot - isn’t it on the same breaker? If so, I don’t believe the plane would be deemed airworthy. Hope I’m wrong.
Am I correct in assuming that the only way to “individually” turn off the AP is via the breakers? Scott, is that what you mean?
I’ve seen the stuff on the ARNAV on/off switch modification, but nothing on the autopilot.
BTW I once thought my AP had failed, as it appeared to be demanding a turn when in the “rdy” state. It wasn’t; it had just disengaged and left a bucket of roll trim in (which I could trim off) but it had me looking for the breaker before I realised the real problem was an out-of-trim aircraft!
agreed, but a judgement call in opinion taking everything into consideration…the 'checklist was in my hand…
I hit the avionics because i could tell (nose forward) the smell was coming directly behind the left side of the panel. Additionally, the GPSS was ‘flying funny’ about 1/2 hour before and i just got the sense (esp. with all the other failures) mine was getting sick.
Withing seconds the smell went disipated and we were on an 8 mile final at 2500ft. At this point i didn’t see/feel the need for a complete ‘master shutdown’.
I appreciate your thoughts and in hard IMC…a different decsion for sure.
forgot,
I had disconnected the A/P prior to a previous landing at RIC…FCI is 6 miles away and doesn’t require the use of the A/P from ‘here to there’ so to speak.
I’m not sure of the exact way to turn of this autopilot. If that’s the breaker, then that is what you would need to do before turning on any master switches. Doesn’t seem to have this step in the POH.
LOL! My IFR check ride DE said “I want to see this flight entirely hand flown. If your autopilot wasn’t also your TC, I’d make you pull the circuit breaker. As it is, if I see ANY of the autopilot lights come on during this flight, you fail right then and there!”.
Could you please email me privately? I have a question to ask you but your posted email address does not go through.
Thanks,
Brian Turrisi bcturrisi@cs.com
if you ever been/removed the glaresheild…you could know in milliseconds where the problem/smoke/fire is and extinguish…
Would you rather continue flight at let’s say 6000 while having a fire behind the glareshield that you otherwise could have handled???
I’m getting the shield off within 5 seconds.
Thanks