Engine Out Over Sacramento International Airport!

[drdehave]

Well, it didn’t progress to full OUT, but it sure as heck felt like it was headed there! Here’s what almost went down--literally--3 weeks ago:

It was a beautiful summer morning for flying, with clear, unusually cool air and a slight headwind. My 2007 Sting LSA was lightly loaded--just me and 13 gallons of fuel. I was headed from Davis, CA (69') 42 nm east to Auburn, CA (1,539'). Sacramento International Airport (26') is smack dab in the middle of the route and I was climbing to 5,500' to stay well clear of its Class C airspace.

Normally, I reduce power above 1,000' AGL and do gradual (500 fpm) climbing to the west of Sacramento’s outer circle, then make the turn east when I have the required 4,100' minimum. But with today’s excellent conditions, the airplane was a 1,000-1,200 fpm virtual rocket at WOT and all temperatures were staying well within the green. So I just left the throttle buried WO for 5+ minutes on a direct heading to Auburn.

As soon as I reached 5,500' directly above Sacramento’s twin 16/34 runways, I leveled off, engaged the auto-pilot and exhaled bigly--sighing the joy of flying! But my joy was short-lived. Within 30 seconds the engine began choking and coughing; it definitely felt like it could die!

I quickly cancelled the auto-pilot, dropped both the throttle and nose, dialed in Sacramento Tower frequency and got ready to tell them I was either coming down on one of their runways, or at the least, I was going to be “nicking” their airspace, as I headed back west to one of three non-towered airports to choose from within a 6-mile radius of each other.

But just as I was about to PTT, the engine came back to smooth-as-silk normal. So I turned back to the west anyway, lowered the nose and throttle some more and aimed her to the nearest airport, Watts-Woodland (125'). In under a minute I was close enough (8 nm) that I could make it, even if the engine went dead. So I sighed bigly again, commemorating that I wouldn’t be ruining Sacramento’s day or subjecting relatives to viewing my “incident” on the evening news after all.

Nevertheless, the engine did have one more serious choking spell before I was safely on the ground at Watts-Woodland. At the tie-downs, I sent a text to both my mechanics about the incident, advising them that I intended to remove both carburetor float bowls to check for debris--a problem that had not affected my engine for almost 1,200 hours, since way back when we were first dragged kicking and screaming into doing the 5-year Rotax (and TL Ultralight) rubber replacement (I had about five debris incidents back then).

As I was removing the first float bowel, it hit me: Not only had both carbs been off recently (twice each, in fact) for repairs, two fuel lines atop the engine had also been simultaneously disturbed for maintenance (new end connections). It was a good bet I’d find some debris in there--and I did. The 2/4 carb had one large piece of rubber and several small unidentified “specs” of debris; the 1/3 carb had several small specs too.

After removing this debris, I put everything back together and flew her home without further incident. That was 30 hours ago. So it’s pretty much confirmed that the whole incident that day was carburetor-debris-related, likely induced by the prolonged, steep WOT climb.

So why am I elaborating at such length about this? There are two reasons. First, we Rotax 912-series operators (especially newer ones) need to keep in mind that, as counterintuitive as it may seem, the best initial response when our engine suddenly turns rough and loses power, especially during or just after WOT climb, may be to simply lower the nose and pull back the throttle. If debris is the issue, this may dislodge it back to a temporary safe zone on the bottom of the float bowl. This is not my revelation; I learned it right here while still a rookie--from Roger Lee--back when I went through my initial 5-year rubber replacement (and carb debris issues) fiasco.

The second reason is to highlight, as Roger has said here before and again recently in another thread the need for (paraphrasing) “...almost hospital-like sterile conditions and protocol when disturbing fuel lines atop the engine.” In this regard, some of you (especially newer 912-series operators) may also find value in reviewing this earlier thread on the subject (along with several Best Management Practices) from four-plus years ago (http://sportpilottalk.com/viewtopic.php?f=19&t=2503).

Now, if I can just find a way (besides continuing to bring it up here) to get my two mechanics to take this subject as seriously as Roger and I both do!

[HAPPYDAN]

And that's why you're a pilot - you're good at it! All's well that ends well.