May 31, 2007

One Of Those Flights…

We're climbing out of Stockton (KSCK) IFR on vectors for the return trip to Hawyard (KHWD). I'm under the Cone of Stupidity, getting some IFR practice. It's a nice warm hazy Central Valley evening, clear VMC, the air's fairly calm, and the Cirrus is climbing nicely towards our assigned altitude of 6,000'. At about 5,000' the oil annunciator flickers on for a second or two, then goes off. I look across at the oil gauges — the pressure's fine, but the temp's way up towards the red end. Hmmm, I think. The oil level was fine back at Hayward; the gauges were fine on takeoff at Stockton. It's really not that hot out there (at least not as hot as it usually is at this time of the year in inland California). The mixture is on full rich; the EGT looks a little higher than usual but not horribly so; fuel flow looks OK; we're not climbing too excessively or anything, at least not in my opinion…. But the temperature isn't going down, even as I throttle back, and the annunciator's now flickering intermittently and almost continuously. I look at Boyan (my safety pilot), and say this doesn't look good, does it? I pull the hood off, level off, and call NorCal Approach to tell the controller that we're cancelling IFR and heading straight to Tracy airport (which I can see about 4 or 5 miles away to my left) due to an oil temperature problem. Quick as a flash NorCal says Tracy's at your 9 o'clock, 4 miles, no traffic observed between you and the airport, do you need assistance?

I say we're fine at the moment, but that we'll head for Tracy and stay on frequency until we're closer. We can easily glide there from here if we have to, and there are any number of fields we could probably land in if we really have to. As soon as we level off the oil annunciator stops flashing, and less than a minute later the oil temperature's down to an acceptable level. I start a slow descent into Tracy, and — of course — the oil temperature is now normal. Everything's looking normal. I tell NorCal we seem to be over the problem, but we'll orbit here for a few minutes around Tracy to see what's happening — my guess is I just had the throttle setting too high for continuous climb (but I'd throttled back a little on leaving the pattern at Stockton, and a lot when I first saw the problem), and something in the back of my mind remembers reading an article by my long-time-ago aquaintance Phil Greenspun where he commented on how easy it was to get his Cirrus to redline on oil temperatures [later: see his article here — there's a comment about it under "Summer Flying")].

So we orbit slowly over Tracy for about five minutes, the oil temperature normal, and I make an Executive Decision (yes, I'm the decisionaliser in this plane): we'll head for Livermore at the current altitude (4,500') with flight following from NorCal, and then decide from there what to do and where to go. I call up NorCal, tell him we're OK and want flight following back to Hayward with the LOC/DME practice approach into Hayward if possible. And much to my relief, the rest of the flight's absolutely boringly normal, with a tiny bit of real IMC on the way back into Hayward on the localiser necessitating a full clearance from NorCal. On the ground I check the oil level — like everything else, it's boringly normal.

[Later: John calls and tells me he heard it all on-frequency (the man's everywhere! :-) ). We have a long discussion about the issue— I think I just need to climb a tad less agressively. Or even less agressively than I already do.]

* * *

Earlier, we'd paused in the runup area at Stockton before departing to give Boyan, my safety pilot, a chance to stretch his legs and for me to get my water bottle out of the back (never leave things like this buried in the bottom of a bag you accidentally put out of reach :-)). I tell tower we'll be off-air for five minutes, and shut the engine off, thinking it'll be nice to take a short break before plunging on again. We just wander around the runup area off 29R for a while, then get back in and start up. The first thing I see is the "low voltage" annunciator staring me in the face. And sure enough, the ammeter is indicating a battery discharge even though the engine (and presumably the alternator) is turning over smoothly. Argh! I check the breakers and a bunch of other obvious things — nothing wrong. On a hunch, I shut the engine down and start it back up again — and now, of course, it's doing what it's supposed to be doing. I keep an eagle eye on the ammeter the rest of the flight, and it's OK all the way back to Hayward, but (especially after the oil temperature issue) I can't help wondering if this is just One Of Those Flights…

2 comments:

Ron said...

The SR20 is notorious for running hot in climbs, even at higher than normal airspeeds.

One of our Cirruses had terrible problems with that for a while. It was also difficult -- nay, nearly impossible -- to hot start. Turns out the problem was that the mag timing was WAY off.

The electrical gremlin doesn't surprise me. The thing about the Cirrus is that it's a more complicated aircraft. There's just a lot more "stuff" on in which can break. In 500 hours of Cirrus flying, I've seen alternator failures, MCU failures, MFD failures, Cmax failures, XM system resets, and more. On the other hand, I flew my Skylane for 800 hours without so much as a hiccup of any kind.

It's the price we pay for all the bells and whistles. I wish I could say the Cirrus was poorly made and that's the reason for the issues, but it's not. Look at the squawk list on an airliner and it's as long as your arm. They deal with it via obscene levels of redundancy, something we mere mortals cannot afford.

--Ron

Hamish said...

Ron — thanks for the comments. I have to admit that I've wondered whether the underlying problem with the engine / oil temperature thing was actually related to an earlier issue with the MP gauge being off in this particular plane (but I thought it had been fixed) or something wrong with the automatic (ha!) leaning system. I dunno — it just seems disappointing that it can still get too hot on the recommended climbout power settings. Next time I'll be a little easier on the poor thing :-).

As for the electrical gremlins, I suspect you're dead on — we just can't afford the redundancy that might make the Cirrus foolproof for the rest of us :-).