February 9, 2014 at 4:18 pm #84825
On Friday I hopped in the 310 and headed down to San Antonio for a Cloud Nine trip. It proved to be an interesting flight, so I thought I’d share.
The flight south to San Antonio would require a fuel stop. En route was going to be interesting, with a winter system involving snow coming through. Most of the areas were going to have tops in the range of 6-8k according to Skew-Ts, with area forecasts showing up to 14k or perhaps into the flight levels for other areas. Freezing level was the surface pretty much the whole way. There was an area that on the progs showed the potential for freezing rain and ice pellets over Texas. Staying at 6k for headwinds was desirable, but obviously not mandatory.
I chose the fuel stop in Arkansas, which would be around 2/3 of the way and before the potentially bad areas. Along the route was IMC with no icing until fairly close to the fuel stop, where at 6k there was trace rime. Easy ILS in, and we checked the weather while refueling. We also got a PIREP on the way in that reported tops at 14k and icing from 10-14k.
Looking at the Skew-Ts, 6k would get above freezing in under 50 miles after takeoff (about 15-20 minutes at the ground speeds we were getting), and we’d been getting trace rime which conditions looked like would repeat. There was a temperature inversion causing the above freezing temps at 6k, but it was also pronounced and both above and below the temperatures dropped enough that I wasn’t concerned about freezing rain/SLD. Rather than trying to go higher and potentially get into worse icing or try to top the system at 14k (possible in the naturally aspirated 310, but could pick up a bunch of ice in the climb and have headwinds), we opted to stay at 6k with the out of turning around back to the fuel stop, which we knew was clear and we could get to with a tailwind. Only trace rime and in about 25 miles it got above freezing at 6k. In solid IMC to San Antonio, but with it above freezing, it was an easy trip.
Heading north yesterday was similarly easy. At 11k we were above the clouds for the first half, and in the bases with no ice for the second half. Visual approach in NH.
The last leg coming back was more complex. NH to OH in the 310 non-stop can require a stop depending on winds. Because there are so many good options to divert for fuel on the way, my general strategy is to check the weather and then divert if necessary. Up until western PA, things were VMC and the flight was going easily.
Once we hit Ohio, we started getting into IMC, and by about 1/3 of the way through Ohio we started picking up trace rime at 6k. We started off going down to 4k to get below it, which worked, but then ended up going to 8k to get on top of it, which in retrospect I wish I’d done in the first place. The boots mostly worked, but left some significant patches of ice on the plane, and the unprotected surfaces also got some (see pictures).
By the time we were over Columbus, it was clear that we’d have less fuel in the plane upon getting on the approach at I67 than I was comfortable with. Furthermore, my home airport is 2800 ft, it was night, there was ice on the plane (although I wasn’t sure exactly how much since it can be hard to tell at night), and after a long day we were tired. The ceilings were such that I was confident we could get in, but I also knew I wouldn’t be happy with the fuel remaining (I’m very conservative on fuel) or the approach to the short field at night with ice. We instead diverted to Dayton (under 50 nm from my home airport), with much longer runways and an FBO that would be open at the late hour getting in.
The 310 handled the ice fine and I noticed no significant difference in performance without it. I still came in a bit fast intentionally (long runway, so no problem) and chose to not extend full flaps since it’s hard to see how much ice was on the tail, especially at night. I also was given “discretion” from 8,000 (above the clouds) to 2,600 (for intercepting the ILS). I stayed high and then dove down at around 1,300 FPM to minimize my exposure time in the ice.
Taxi up to the FBO, call the line guy (who was out fueling the airliners), and got a crew car to drive to my house. Since it was 1/2 SM FZFG this morning, they weren’t worried about getting the car back in a hurry. I’ll go return it here in a bit and ferry the 310 home. Weather is improving, I’ll probably head over after lunch.
Since I’m based at an airport that has a short runway and not a great approach, I accept that I may sometimes need to divert to a better airport nearby. This is fine by me since there are some great options for it. In being here for about 18 months this is the 2nd time I’ve had to, so I think that’s an acceptable compromise given the other reasons why we chose to base the plane there.
I think the key takeaways from this trip were:
1) Go into the weather with a plan appropriate for the conditions. I know a number of people with ice who have a SOP of “climb to [whatever] altitude and then evaluate” or “climb above it”. Anything short of an SR71 or U2 will have weather it can’t top. While topping IMC is often a good idea, it can also be a good idea to be either below it or in it, as was shown on the flight south.
2) Never be afraid to divert, even when the airport is <50 nm from your destination, and always have plans to divert. In my case, starting from eastern OH when I got into the soup, I had contingencies. First Akron, then Columbus, then Dayton. I figured out on the eastern side of the state that I almost certainly wasn’t going to make it to my home base and was fine with that.
3) However you do your risk assessments, update them in-flight and make changes as appropriate to your plans.February 9, 2014 at 4:32 pm #103273February 9, 2014 at 4:33 pm #103274February 9, 2014 at 10:48 pm #103279
Great write up Ted. Another fine example that with adequate 4 dimensional planning, good equipment, an open mind, and flexible alternatives, most flights are possible!February 10, 2014 at 12:57 am #103281
After lunch I drove the crew car (a Cadillac STS – not bad for a crew car!) back to Wright Bros Aero at Dayton, paid for the tips to get topped off, and was on my way for the <50 nm flight home. Filed but was VMC the whole time with an easy approach on the mostly clear runway.
Jim, you got it right – most trips with these planes are possible. They are very capable and give us a lot of options. The real key is being flexible and willing to change plans en-route. I even got to sleep in my own bed last night, so that worked out nicely.February 10, 2014 at 1:47 pm #103287
Great trip and write up Ted!
RobertFebruary 15, 2014 at 8:15 pm #103460
Very good and interesting read Ted. Thanks for sharing. That’s a good amount of ice on the wing root!
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