Alex and I set off from Boston Tuesday on a trip via light aircraft to northern New Jersey, Washington, DC, Norfolk, VA, and Gettysburg, PA. I try to avoid flying in the clouds and I try to avoid flying in the dark. But there was a cloud deck over New Jersey at about 2500′ above the ground and the weather for Wednesday was forecast to be much worse. So it was going to be a flight through at least some clouds. If I had been alone I would have left around noon but a friend wanted a ride for the first leg of the trip and couldn’t leave work immediately. So we didn’t take off from Hanscom Air Force Base (Bedford, MA) until after 3 pm. Knowing that there would be clouds in New Jersey and not wanting to deal with the complex air space around New York City, I filed an instrument flight rules (IFR) plan. Knowing that it would be dark when we arrived I decided to go to Teterboro airport where they have a precision instrument landing system (ILS) rather than cheaper simpler Essex County Airport where they have smaller runways and no ILS (Essex County is where JFK, Jr. kept his Piper Saratoga; Teterboro is closer to Manhattan but horrifically expensive for fuel and other services). From the weather forecasts that I’d seen it sounded as though 6000′ would put me above the lowest deck of clouds and below the higher decks. That was indeed true until around Hartford, CT. Then we were headed straight for the top of a cloud. The dog in the back didn’t budge from his sleeping position but I could feel some tension from the right seat. “Why aren’t we climbing to get above that cloud?” my passenger asked.
An instrument clearance means that Air Traffic Control (ATC) has cleared a block of airspace in front of you of any other airplanes that are also flying under IFR. The pilot is still responsible for looking for visual flight rules (VFR) airplanes when out of the clouds but it is ATC’s job to keep everyone inside the clouds separated from each other. The system only works if pilots don’t deviate from their clearance, which includes an assigned altitude. This I explained just as we went into the cloud top. In addition to obscuring one’s view of the horizon clouds have a nasty habit of containing turbulent air. The airplane rocked a bit.
The real problem with flying in clouds in the New England winter is airframe icing. Whenever the temperature in a cloud is below 0 C there is a risk of ice accumulation. The temperature, on average, drops 2 degrees C for every 1000′ rise in altitude. So at 6000′ it was about 12 degrees colder than on the ground or -2 C. A simple airplane such as my Diamond Star DA40 does not have heated wings, a heated propeller, rubber boots along the wings that can crack ice, or a system for spreading antifreeze out onto the wings. It does have “pitot heat” to make sure that the instruments for measuring airframe and altitude don’t have their air intakes frozen shut. I had turned this on just before entering the clouds but it is only helpful for maintaining airplane control while getting out of the ice. My rule for instrument flying in the winter is that I won’t go unless it is above freezing at 3000′ above the ground. Because there are no mountains or other obstacles over the coastal sprawl of the East Coast it is always possible to descend to 3000′ without fear of hitting something.
After 15 minutes in the clouds small amounts of ice began to accumulate on the “wing walk” grippy surface next to the cockpit. Airliners and the one small airplane on the radio (New York Approach) were complaining about ice accumulation and asking for lower altitudes. The helpful controller said that people a few miles ahead were reporting ice and asked me if I wanted lower. I was cleared first to 5000′ where the temperature was 0 and the ice accumulation stopped but the built-up ice did not come off. At 4000′ the temperature was +2 and the ice quickly disappeared. We were still inside the clouds at 4:30 pm when the sun was supposed to set so we noticed only a rapid darkening of our surroundings.
Teterboro airport tends to be busy and a day with low clouds when everyone is coming in IFR slows things down considerably. In theory ATC should have parked us in a holding pattern somewhere. I would have been responsible for driving around in fairly precise ovals, 1 minute long on the flat side, at some precise point in space. In practice the New York controllers are so good and they have complete RADAR coverage so to be nice they just gave me vectors that took me northwest of Teterboro until it was my turn to come back in. With vectors they just say “fly heading 270” and you point the airplane west at the present altitude. After about a 10-minute vector delay we were turned back in towards Teterboro and cleared down to 3000′. We didn’t break out of the clouds completely until we were at 2000′ and heading in towards Runway 19 at Teterboro. It can be a challenge to locate a runway amidst the clutter of parking lot and street lights in an urban area but the Teterboro runway is 7000′ long and has a fancy centerline lighting system. In any case it isn’t necessary to visually identify the runway until several hundred feet above the ground. An ILS is flown by tracking two radio beams emanating from just in front of the runway. The localizer beam gives left/right guidance and the glideslope beam gives up/down guidance. Deviation from the center of these beams is displayed on a little round dial on the airplane dashboard. Not wanting to trust my perceptions in the dark, I flew the gauges while running the pre-landing checklist.
Once on the ground we taxied off the runway as fast as possible because there was a huge Gulfstream business jet right behind us, moving at more than 2X the speed of the little Diamond Star. Both of us taxied into Jet Aviation, one of the airport gas stations at Teterboro. Their parking lot this Tuesday before Thanksgiving was crammed with business jets and turbine-powered helicopters. There were probably $2-3 billion worth of airplanes on their ramp and in their hangars. The Jet Aviation staff took our bags from the plane through the palatial terminal into a waiting Hertz rental car, a little over 2 hours after we’d taken off from Bedford and about 3 hours after we’d left Cambridge.
Next stop is Washington, DC. We have a big family dinner there at 4 pm on Thanksgiving Day but the weather forecast calls for clouds, rain, strong headwinds, turbulence, gusty surface winds, etc.Full post, including comments