Saturday, June 4, 2011

Anatomy of a late-winter cold front

Position: 30nm northwest of Gorman VOR, abeam Bakersfield, California.
Altitude: 10,000'
Groundspeed: 161 knots
Fuel flow: 8.5 gallons/hour
58 minutes from home

The last remnants of southern California suburbia, still basking in 80-degree sunshine have just disappeared behind the mountain range separating them from the San Joaquin valley. Beneath me, oil wells and supporting infrastructure dot the surface. To my right, Bakersfield is barely visible in haze while beyond it the Sierra crest is illuminated in sunshine. To my left, the eerily symmetrical hills on each side of the San Andreas fault are in plain view, and the coastal near San Luis Obispo and Morrow Bay barely visible as a thin layer fog butts up against the coastal hills.

A late winter (this is June, mind you) low-pressure-center storm is approaching the coast. Hundreds of miles ahead of it, where I am, the sunshine gives way to a high overcast layer of cirrus clouds many thousands of feet overhead; the clouds will coalesce, darken, and slowly slope down to the surface over the next 200 miles, the air driven upward to condense by a thin wedge of colder air called a cold front whose position at the Earth's surface is still well out over the pacific. Winds of about 35 knots at this altitude, swirling counter-clockwise around the low are giving me a 15 knot boost in ground speed, while forcing me to point the airplane about 8 degrees left to maintain course.

The Mooney is still in smooth air, for now, and is completely "in the groove" -- holding altitude within 10 feet without any control input, wings remaining level with just an ounce or two of pressure on either rudder pedal very occasionally to hold the wings perfectly level... no autopilot necessary. I search for some non-Spanish-polka music on the ADF (which picks up all the AM radio stations). Not bad for a 45-year-old airplane....but mostly I'm happy because I'm getting excellent gas mileage with the tailwind.

...three hours earlier: The examiner places a piece of paper in the throttle quadrant to block my view of the fuel-air mixture levers. He pulls one to cut off fuel to one engine and the mighty (not really) Piper Seminole's nose lurches off to the left. Now its time to do the routine:

Maintain directional control: By stomping on the right rudder, raise the dead engine slightly with aileron, pitch for blue-line airspeed
Everything forward: Mixtures (except the one he pulled), props, and throttles
Everything up: Verify gear & flaps up
Identify: dead foot, dead engine
Verify: dead engine by pulling the left throttle back
"Don't bother trying to troubleshoot, pretend its got oil all over it" he tells me. Fair enough, one less thing to screw up.
Feather: Pull back the left prop control

The windmilling propeller comes to a rest after a few seconds, its blades now turned to slice into the wind. The hundred+ pounds of rudder force I'm holding can be reduced significantly as the drag produced by the windmilling prop goes away. This thing can still fly, but won't quite maintain 5,500' altitude, even with only two people aboard.

In another 30 minutes we complete the test. I've made a couple of small mistakes, but everything was satisfactory. As usual the examiner taught me a few things that I'll try to file away in memory should "bad things" happen someday. Come to think of it, every examiner I've had in the past has mentioned a few things of that nature and I can remember most of them. I now can pilot multiengine airplanes. Another goal checked off my list.

...20 minutes later: The smooth flying "in the groove" has given way to intermittent light turbulence and transition through a couple iterations of mountain wave from the coastal mountains. Small, low-altitude versions of lenticular clouds are visible over the Santa Lucia crest above Big Sur. The ceiling is nearing my altitude, with home reporting clouds at 11,000'. The temperature has dropped from 8C to 3C at this altitude in the last 20 minutes. Its nearly time to start down though, and its looking like this trip will be completed without having to worry about clouds or ice.