Posted by: Orlando Web Services | September 4, 2011

Cirrus Cylinder Head Temperature Redlines

August 29th was an important day; it was my youngest son’s birthday and he was turning 14 years old. He doesn’t seem so young now or as small as he once was and now that he is advancing nicely playing bass guitar, he is almost more of a room mate. His soon to be 16 yr old brother is even more to my eye level and size. Anyway it was going to be a day of celebration including a dinner out and ice cream and cake afterwards.

Around 10am I got a call from Gordy, my flight instructor / mentor who expressed an interest in taking the Cirrus up and going from Penn Yan (KPEO) to Rochester (KROC). There at KROC he wanted to do a few ILS approaches and figured that I might want to ride along. I thought it would be a nice flight and it wasn’t going to interrupt birthday plans, so I agreed. Gordy would pick me up in a couple hours and take us to Penn Yan.

During my wait I collected my log book and made a copy of my hours and endorsements and put them on file. I like to have another hard copy of things just in case I was to loose my log book or worse. When flying the Cirrus I want to make sure all my ducks are in a row. Why? Well as much as I like high tech gadgets, I am not a fan of advanced automation. I’m not against it…but too much of any good thing can be bad. I would love a large KILL switch that I could push to remove the autopilot, electric trim and so on…just in case the plane decided to do its own thing. The idea of “looking” for circuit breakers while I arm wrestle with a plane isn’t my idea of fun. The world is not moving in my direction, so I must move with it…which is why I am riding along.

On the way to Penn Yan between the normal chit chat sessions we talked about the Cirrus, ours is an SR-20 with an upgraded autopilot. Gordy mentioned that another member flew it and had to turn back near KSYR due to the cylinder head temperature on the #4 cylinder redlining. Apparently cylinder #4 went red in cruise flight and then calmed down. They brought the plane back and grounded it temporarily…until our flight. I don’t remember what happened between flights, but hearing this in route was not encouraging.

We got to Penn Yan in short order and took care of all the pre-flight and started our flight by heading northwest towards KROC. At around 3,500 ft and in cruise Gordy decided that we should lean the plane. So with me in the left seat I pressed “lean assist” and let him handle the mixture control. Generally we are pretty good at coordinating around each other and he found the first peak. I think we were trying to find lean of peak (or rich of peak), I forgot which at this point, but for some reason neither was working out. Gordy tried it a couple times, still no luck, so we just clicked “normalize” and contacted ATC to request a touch and go landing using the ILS on runway 22 at Rochester.

I was flying the plane in KROC airspace while Gordy handled the radios. We did the pre-landing checklist and with the ILS setup on the primary flight display I turned on a long final for runway 22. So far…so good…I trimmed as needed and tried to keep the glide scope where it should be on the PFD (primary flight display). This was starting to get fun! I was around 100 kts and pitching as needed to keep things centered. The runway was clearly in site, but I tried to ignore that fact and used the display as much as I could.

I finally had Gordy take the controls for the landing, it had been awhile and I didn’t want to kick the rust off on the main runway and be on TV if I screwed up. Gordy did just fine and we landed on 22 and just as quickly he brought in 50% flaps…away we went on the touch and go! We were climbing and turning right traffic for another ILS approach and didn’t have any issues as we headed outbound on a heading of 280 at 1,600 ft climbing to 3000 ft. We called up ATC and were now told to turn to a heading of 360.

By now the airspeed was between 115 to 120kts. Our oil temp was 171 F and the oil pressure was 50 PSI which is all within the GREEN.

Suddenly Gordy noticed a red light. He quickly turned the knob on the display on the MFD (multi-function display) to the ENGINE page and saw that cylinder head temperature on the #3 cylinder was at 468 F – REDLINE. Everything else was fine and the plane was cruising along as it should. We quickly went to full rich and reduced power and declared our condition to ATC.

MFD Showing a Redline on #3 (simulated)

As all of this was going through my head and as Gordy was talking to ATC, the CHT temperature began falling. We weren’t ready to declare an emergency just yet. We still had the airport in site and things were going from RED to Yellow and then back to GREEN all in about a minute’s time. Weird!

——————————————————

If you want to hear what happened, you can by clicking the link below. We are N8PY – Gordy is the first voice you hear with our request.

http://archive-server.liveatc.net/kroc/KROC-Aug-29-2011-1700Z.mp3

On the tape at 2:48 to 3:07 – We are told to turn 330 after being stepped on.

At 3:49 we are told to maintain VFR at 3,500 ft (as a plane flies below us).

At 9:22 we begin our decent to 2,500

At 10:30 we are told to turn left 250 maintain VFR cleared ILS 22 approach.

At 12:14 we are told to switch to the tower frequency.

At 12:51 we tell the tower where we are and we are cleared for a low approach. We request a touch and go and then another try at the ILS. Finally we are cleared for the touch and go.

At 12:14 we are told to switch to the tower frequency.

At 16:50 we’ve completed the touch and go and are climbing out, we are switching to departure for a second go at ILS 22.

At 17:31 we are at 1,600 climbing to 3,000 on a heading of 280. So far so good!

At 17:40 we are told to turn on a heading of 360.

At 18:40 we are asked how the approach will terminate – we respond at we will be flying direct to KPEO. We are cleared to fly runway heading maintain VFR after the touch and go.

At 20:09 we notice our REDLINE and we report that we have a problem with our engine and have a request that we go direct to Penn Yan. We are cleared direct to Penn Yan.

At 20:45 less than a minute from reporting a problem, the CHT is back in the green and report that a cylinder was overheating – we are instructed to turn to a heading of 100.

——————————————————

As you can hear, Gordy requested a heading to Penn Yan after the engines CHT returned to normal. We eventually turned direct to KPEO after leaving KROC airspace. On the way back Gordy wanted to see if we could lean the engine. I successfully negotiated that we don’t push our luck. I didn’t want my son’s birthday to be the same day his daddy (me) died. Gordy…to his credit…left things alone.

Back on sweet mother earth we grounded the plane. The plane was quickly scheduled to be looked at in Batavia to see what was going on. This was the second time that a cylinder redlined and returned to normal. This occurred with #4 before us and now #3. The leaning issue was the only other one reported besides Gordy feeling the engine running a little rough, he flies this aircraft more than me so I didn’t notice it like he did.

The Cirrus was flown by Gordy a few days later to Batavia for a checkout. Apparently each cylinder head has a discreet temperature probe. We had problems with the number three cylinder head temperature readout being hot…they switched the probe from the number three cylinder to the number five cylinder and the probe from the number five cylinder was placed on the number three cylinder….same for 2 and 4.

Cylinder Head Temperature Probe

So now when you go to the engine monitoring page on the MFD and look at the temperature readouts for the cylinders, things are not what they seem. The indicated temperature for cylinder three is actually cylinder five and vice versa, this will allow us to troubleshoot the probes.

Cylinder Head Temperature Probe Closeup

If the probe for cylinder three reads high again, the probe is probably bad because it is actually reading the temperature of cylinder five. If the probe for cylinder five reads high, then it is actually cylinder three overheating and the problem is probably not probe related.

So the saga continues! Is it the temperature probes or the cylinders? I guess we will find out eventually once some lucky Joe flies the plane and replicates the proble

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Responses

  1. Hi there,
    I enjoyed reading your descriptions and experiences. Just wondering if you’ve gotten to the bottom of this cylinder temp issue, whether it was the probe or not, as we’ve just had the same thing happen in our SR20. Oddly it was cylinder 3 as well. It happened soon after take off under full power and mixture rich, climbed into red fairly steadily from orange which was when we noticed it. As soon as this happened we fulled the power right back and returned to the airfield. It returned to green well before we got back on the ground.
    Clearly it’s a bit of a concern, so any info you have would be appreciated!
    Cheers

  2. The problem didn’t return, however we think it had to do with the fact that it was a hot day 85F or more, which made conditions just right causing this to happen. I haven’t flown in it since…but that was the conclusion we came up with.

    Wish I had more flying adventures to post, but money is tight right now and price we rent the Cirrus for keeps going up.

    Blue skies!!!

  3. You probably had a clogged injector on your #3. Whatever it was worked it’s way out eventually and that’s why you didn’t see the problem return. Just had this happen to me as well on taxi. We abort takeoff and had the mechanic tow it back to hanger. He opened it up and it was a piece of foreign material in the injector. It’s a very simple process to clean them so I would recommend you do this just in case (clean em all).

  4. Interesting. Our problem cleared up in flight a few moments after it started, so we never had a mechanic take anything apart. So far so good!

  5. It’s same thing happened to me today…. Number 3 broke 500f….
    I agree the clogged cylinder makes sense BUT you would also see a rise on the EGT which I did not more did the above pilot mention. I would love any more details if this has happened to anyone else.
    Thanks


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