When clouds bring loads of ice, pilots must reach for all the tools in their toolbox.
The nice thing about Learjets is that you can almost always vault completely over weather that would cause other aircraft no end of trouble. And so, it is with some concern that we are sitting in the pilot’s lounge at the FBO in Columbus, Georgia (KCSG) planning our 1,933-nm return flight to Washington state, and studying some nasty weather that it looks like we will have to land in, rather than simply just jumping over.
It is 52 degrees and sunny in KCSG and clear and 31 back in Seattle. But in between, the entire central part of the United States is suffering from a blizzard due to a series of lows that extend all the way from Houston to Fargo, North Dakota. These are slowly moving east and carrying with them a huge load of water they picked up while over the Pacific Ocean a thousand miles out to the west. As they move east into colder air, all that water gets dumped, creating a mess of low ceilings with cloud tops well into the flight levels, plus blowing snow, ice, freezing mist and drizzle near the surface. The system is so large that in looking at the weather chart, we cannot see any way to readily fly around it, no matter how big of a dog leg we are willing to make.
To complicate matters, the winds aloft are howling from the northwest at more than 100 knots, which will give our 465-knot Lear 40 an effective ground speed of about 350, thus reducing our range to a bit under 1,000 nm. This severely limited our ability to “vault” over anything. This also means we will need to land somewhere in the middle of the weather mess for fuel. The immediate conundrum is where to make that stop.
In looking over the TAFs, nearly all of the airports anywhere near the midpoint of our route are forecasting ice, plus freezing mist or drizzle and low IFR conditions. For pilots who have flown a long time in the northern states, snow is not too bad, but water that can’t make up its mind if it is frozen or liquid, that’s not good at all.
The de-ice systems on a Lear’s polished leading edges get hot enough to fry an egg. So it is not so much excess ice accretion on the wing that we worry about as all the rest that goes with it. With a touch down speed on the order of 125 kts, we are concerned about stopping the airplane safely on the runway if surface conditions are icy. If surface conditions are icy, glare ice will be particularly bad.
Then there is the practical matter of what to do about the ice accumulated during the approach when it is still frozen to the airplane after the refueling quick-turn is completed and we are ready to leave. What happens if we get stuck and have to park the airplane for the night at that location? When winter conditions deteriorate, heated hangar availability becomes as rare as hen’s teeth and can be very expensive. But if the airplane spends the night outside, the next morning you may find a large non-aerodynamic ice cube that only has minimal resemblance to the shiny, sleek airplane you left out last night.
Of course, assuming the equipment is functioning, you can get the airplane de-iced. But the de-icing fluid is four times the price of fuel at $16.95/gallon and (reasonably so) the line guys always seem to be more concerned about removing ice than how much of the expensive de-icing fluid they are casually spraying all over the place. The process can easily use 30 to 50 gallons, which adds about $800 to the fuel stop expense. This potentially may prompt the bean-counters to ask why you chose to land there in the first place. All kinds of things to consider and we haven’t even left Georgia yet.
We aren’t the only crew members standing around in the Columbus FBO pilot briefing room, grousing about conditions to the west, looking at the weather reports on the computer screen, and thinking that if this was a personal flight, we would just bag it, or better yet fly the airplane south for a half-hour and spend the next several days on the warm beaches of the Florida Panhandle. but that is not to be.
Then, one of the pilots from a swept-wing Citation parked next to us on the ramp who is also westbound noted a potential solution. In looking at the weather on the computer screen, he points out that due to a peculiar scalloping on the systems eastern edge, North Platte Nebraska (KLBF) is being temporarily spared from the worst of the storm. It has an airborne hole in the ice with its opening facing toward us. They are calling for 1,500-foot overcast, visibility of seven miles, surface winds from the north at 10 to 15 kts with occasional blowing snow, but no forecast of freezing rain or mist for the next 2 to 3 hours. KLBF is just 914 miles away and has an ILS to runway 30. The FBO is Trego Dugan, which is the same company we used at Grand Island on the way out and has jet fuel priced at just $3.56/gallon. Perfect. We file right away, quickly load our passengers and beat the Citation off the ground by 3 or 4 minutes.
It is my leg to fly and we soon leave the clear conditions behind us and enter the leading edge of the winter low pressure weather system to our west. Six miles beneath us, semi-trucks on the interstate are losing traction and causing huge multi-vehicle pileups. For us, we are still IMC as we pass through the mid 30s with just some light-to-moderate chop, which is causing the airline crews nearby to look for a smoother ride. Going through FL390, we finally break out into a clear, very cold and sunny sky. We settle for FL430 where we find the temperature to be at ISA -6 and a ride as smooth as silk. For the next two hours, we eat thick ham sandwiches, sip rather good FBO coffee, and are all alone up there in the bright sunshine apart from a Gulfstream going the other way a couple thousand feet above. Somewhere behind, from time to time when our center frequencies match, we can hear our Citation buddies from KCSG coming along behind us.
About half-hour out from KLBF, we see on our iPads that the weather has deteriorated a bit more than was predicted with the freezing drizzle now back on the line. We decide there could be a lot of ice in the clouds under us, and decide to stay high as long as we can by entering a TOD (top of descent) into the Universal FMS much closer to the airport than we normally would. If there is ice, the faster you go, the better, and the controller helps by telling us to keep our speed up as much as possible, as we are number one for the ILS, with a Citation close behind. We come out of 18,000 at over 325 knots descending at 4,000 fpm and ask the Citation what they need us to do in order to maintain spacing. Their reply is 250 kts. To us that seems a bit slow given the ice, and so with speed restrictions released, we keep the angle of attack low, and the speed above 300.
The IAF (initial approach fix) for the KLBF 30 ILS is OMESE and we come charging down to it with all the
de-ice equipment on, the spoilers out and the power at a good 65 percent to keep everything hot. On reaching the initial approach altitude of 4,700 feet, the spoilers stay out as the pitch goes up, which rapidly decelerates the airplane to flap extension speed. At that point, almost simultaneously, the spoilers are retracted and the flaps are lowered (spoilers out with flaps down is prohibited in a Lear 40).
Shortly thereafter, we are established on the glide slope with the speed down to 150 knots, flaps at 40 degrees, three green on the gear and the autopilot plugging in a 10-degree wind correction angle to the right. Somewhat surprisingly, we break out at about 1,700 feet AGL and can see the airport about 3 miles away through a windshield fringed with ice. Knowing the airplane is carrying ice, I want to get a feel for how it is handling well before landing. I shut the autopilot off but keep the speed up 10 knots above the Vref of 125. I brief the PNF that I intend to transition from a crab to a slip over the approach lights, touch down a little early on the right main first, then either make exit C3 on the left, or if braking seems poor, just let it roll to the end. He concurs, saying, “Yep, that’s what I would do.”
The touchdown goes as planned, and hearing the Citation behind us reporting established on the localizer, we get the reversers and brakes going and make C3 without any slipping or sliding. The Citation lands shortly after we exit and lets it run to the end of the runway, which is not good for us because that puts him much closer to the FBO and fueling truck. The Citation crew however comes to a complete stop after exiting the runway, and stays there apparently running their after landing checklist. Seeing that happening, I pick up the taxi speed a bit, and beat them to the wand-carrying line guy next to the fuel truck by about the same amount of time our departures differed back at KCSG.
We open the door and get out of the Lear to find its de-icing equipment has worked quite well. There is a little bit of rime ice on the winglets. It is nothing we can’t remove by hand that would prevent us from taking off again as soon as our fueling is completed. Not so for our Citation-driving buddies. They must have kept their airspeed low and angle of attack too high while descending because the bottom of their wing and vertical stabilizer have so much ice that even our passengers comment on it. Standing at the FBO’s counter, they ask if the de-ice truck is working and about how much it will cost. The estimate could easily pay for a month’s worth of crew meals. With considerable trepidation, they retire to a private area of the lounge to call their company for approval.
While the line guys are trying to get the de-icing truck’s frozen engine started for the Citation, we are loading up while giving thought to the departure. Obviously, it would be better to not fly when icing conditions exist. But if you must, the safest strategy is to make sure all de-ice systems are operating, then get airborne as soon as you can and climb above the icing levels just as fast possible, all the while keeping the horizontal
speed up as high as the airplane will do and still climb well. A lightly loaded Lear 40 will climb 4,000 to 5,000 fpm while doing 275 and 300 kts in the horizontal. In our case, this means that if the climb is unrestricted, we will be above the icing levels at about 4 minutes.
With this in mind, we call Minneapolis Center on their remote frequency for our clearance and request (for reasons of ice) no delay in our climb after takeoff. They understand the problem completely and come back with a clearance directly to the mid-30s.
Five minutes after takeoff we are in bright sunshine, and a bit later, land in Seattle where it is clear as a bell. With nasty icing conditions now just a distant memory, we think, “Nice trip.”