Saturday, June 14, 2008

Captain, We Need More Power!

Interesting times at the Home Base since MS and the IFR Pilot returned from NOLA. Unmentioned in the prior post was the borderline scary takeoff from the Home Base's 2350 foot runway. Picture this: It was about 91 degrees F outside. We had some baggage, fuel to the tabs, and two bigger-than-FAA-standard people on board. In other words, we were right at the edge of the W&B envelope. Then, add in what seemed to be a 60 degree crosswind (instead of a helpful headwind!). The result was a meager, meager, meager climb rate off the Home Base's Runway 3, which has these pesky little TREES just beyond it. We cleared 'em, but I swear I could count the leaves...

So, when the mechanic called the next morning and said, "I saw that takeoff. Your plane's coming into the shop when you get home," MS and I both knew we needed to heed his advice. (Of course, every other takeoff during the trip was absolutely fine, though we did consciously choose to refuel at airports that had generous runway lengths.)

Upon our return, mechanic extraordinaire B fetched Mike Hotel from the hangar and began checking things. Compressions. Exhaust system. Lobe wear on the camshaft. Alternate induction air door. Everything. MS and the IFR Pilot scoured the internets for data about the Arrow IV and the Lycoming IO-360-C1C6 that powers it. We had run all kinds of experiments on the way home to see how Mike Hotel's performance compared to the POH; the results showed that we were in the target range for an that's 1500 hours toward a 2000 hour TBO.

The only thing that B uncovered was an enlarged hole on a plate or some other kind of thingamajiggy on the propeller governor. His theory was that although we had the prop control full forward, we might not actually have been getting the full bite of the prop because it was taking whatever pitch it wanted. So, he pulled the governor and shipped it across the state to our new friends at Tiffin Aire for a rebuild. I'll admit I wasn't sure I understood all the details about how this could explain what we were seeing, but I understood that something was out of spec and needed to be fixed. I also sucked in a deep breath when B delivered the foreboding announcement that the rebuild was going to be expensive.

A couple days later, B installed the new governor and MS and I convened at the Home Base for the test flight. We had already determined that he'd be the guinea pig, I mean, test pilot, so by the time I arrived, he was already doing the run up. I watched with baited breath as he accelerated down the runway, Mike Hotel pitched up, and then soared into the sky. It was a glorious sight, right up until MS landed. Let's just say that it wasn't one of his best -- though the wind was being a bit squirrely.

The IFR Pilot then jumped aboard and we did another takeoff. We paid particular attention to acceleration and where on the runway we were achieving each 10 knots of airspeed. We had sufficient airspeed by the halfway point to perform a short field takeoff in accordance with the POH, and by the time we had cleaned up and hit the end of the runway, we were established in a 500 FPM climb at 70 KIAS. Looking good!

Down to BJJ we went for a few more takeoffs in different configurations. Everything was on the money (well, except for MS allowing us to get blown way past final on the first landing), so we turned tail and headed back to the Home Base. We decided to add fuel to the tabs and go for one more takeoff.

Things went like a charm on the final trip around the pattern, and we concluded that it was acceptable to declare Mike Hotel operational. It's a happy, happy plane now, as it also got an oil change and a new pilot-side vent window while it was in the shop.

Back to normal flight ops here at My Flying Blog. Thanks for reading!

1 comment:

phil said...

those trees on short final of the landing video need some trimming.