Flying the MU-2 in Not So Good Weather

Spring Weather is Here
Although I have gained some decent experience flying in all kinds of weather, our flight the other day reminded me that the spring weather is well on its way.

The winter months out west are usually defined by cold, stable, dry air. If there is precipitation, its usually so cold up at altitude that icing on your wings is not as much of a concern as it is in the east. Well, now its mid-March and the nice, stable, winter weather is beginning to wane. Spring is usually accompanied by warmer, moist, unstable air masses that are the perfect recipe for building thunderstorms.

I checked the weather and filed our flight plan before we departed. The radar definitely showed some green along our route. The reports also indicated a few thunderstorms were possible in the area with the tops around 30,000 feet. We fly as high as 25,000 feet so there was no chance of going over any thunderstorms.

We loaded our passenger and I cranked the turbine engines up. It was my leg flying out to the dirt strip. I departed and turned on course and we punched into the clouds around 3,000 AGL (above ground level). Initially during our climb the ride was fairly smooth. But, as we neared 15,000 feet we began rocking a bit, just as the weather briefer had advised me; the greatest chance for turbulence and icing was between 15,000 feet and 18,000 feet. I was hand-flying the airplane because I am still trying to really get acquainted with it. Leveling off at 23,000 feet, I accelerated to about 280 knots true airspeed.

Heads up from ATC
About twenty minutes into the flight the air traffic controller advised us that there was a heavy band of precipitation at our 12 o'clock (right in front of us) and a distance of about 20 miles. Jose (my chief pilot) flipped on the on-board radar. We could see that there was some green ahead, but no yellow or red. Green is precipitation, yellow is heavier precip and moderate turbulence, and red means, "stay the heck out of that stuff!" Over the radio, we could hear all kinds of pilots in the area asking ATC for deviations around thunderstorm build-ups. The controllers were also generously giving recommended turns to the left or right for pilots.

Here we go!
I continued on. About five minutes later, it got rough. I have flown in the clouds with some occasional moderate turbulence before and its kind of unnerving. You're trying to focus on the flight instruments and all the while you are being tossed about and the tail of the airplane is swaying back and forth (called yaw). When you train to fly under zero visibility, called IFR, you are taught to trust the flight instruments and keep the wings level during rough weather, no matter what. Today, that training definitely kicked in. I was also getting about 700 feet per minute updrafts and downdrafts. This means that the unstable air was causing the airplane to undesirably climb or descend. I had use both pitch and power adjustments in order to attempt to maintain my assigned altitude. Again, as pilots are trained, keeping the wings level is the number one thing here. Also, keeping your head movement to a minimum will help prevent you from experiencing vertigo, which is when a pilot becomes disoriented as to which way is up or down.

We kept a watchful eye on the wings for the nasty white stuff. Ice. We only accumulated a small thin layer of rime ice on the leading edge of the wing. The funny thing is that the airplane had just received brand new ice boots and I know we were both kind of wanting to test out our new deicing equipment. Although, pilots generally do not want ice forming on their aircraft. You are supposed to wait until you build up at least 1 to 1 1/2 inches of ice before you work the boots to pop off the ice. Otherwise, you may create an ice bridge between the boot and the ice if you do it too early. Then, as ice builds up more and more on the ice bridge, you are unable to remove the ice when you really need to. We, however, never had enough ice to cycle the boots. Darn!

Don't use the autopilot today!
The turbulence, the updrafts and downdrafts, and the pounding precip on the windshield continued for about 30 minutes. I had to keep hand-flying because you are not supposed to use the autopilot in icing conditions; the pilot needs to be able to feel the force changes on the controls if ice alters the airflow over the wings. This is one of the main causes of the Flight 3407 crash in Buffalo, NY in early 2009. The crew was operating in pretty good icing conditions with the autopilot flying the airplane. Essentially, the airplane/autopilot stalled the airplane and it spun into the ground.

Jose even asked me at one point if I wanted a break. I told him that this is a single-pilot airplane and I had better learn to deal with these situations if I am someday going to fly it alone. One day, he would not be here to "give me a break." He agreed.

We finally got out of the crummy weather. Just for kicks, we operated the wing boots and watched some of the ice pop off. Ahhh...new deice boots! We smiled at each other because we both know how important those wing boots are to us.