I had to fly a business trip LESB-LFBO earlier this week and as my hangar neighbour says, it is being weird weather all around these days. Note he flies a PC12NG.
The weather picture looked challenging for the day of the business meetings, and a bit better the prior day. In fact on the planned day, the LESB opening time was really tight for my appointment and there was some uncertainty as to how quickly I would be able to process myself towards groundside so I decided to fly the prior afternoon.
There was a slow-moving occluded front (in fact the prior day it showed as a warm front) paralleling our route from the Med to the Pyrenees with extensive cloud cover at medium levels, rain and worse still, icing predicted in cloud which would affect the IFR flight.
OTOH a VFR low-level flight would not be possible across the Pyrenees due to mountain obscuration. The alternative along the coast would be rather bumpy with severe turbulence forecast between ground level up to FL070 with 50KTS winds from the SE from Perpignan to Toulouse.
My departure was timed to be as late as possible during the day while still aiming to be ahead of the band of weather preceding the NE-moving front.
The FPL route was actually in the middle of the weather for the first half, which would mean climbing through icy clouds between around FL90-120. I was light so should be able to climb through it in five minutes…if no significant ice was loaded. Once over the Pyrenees the cloud would clear, but that would not mean NOSIG, since our destination showed:
TAF LFBO 181100Z 1812/1918 13018G30KT CAVOK
TEMPO 1812/1902 13026G40KT
PROB30
TEMPO 1904/1912 BKN014
TEMPO 1914/1918 13025G40KT
Clearly the blistering surface wind was the cause of the forecast SEV TURB SIGMET, but the SIGMET was just East of Toulouse and below FL70, which should keep us out of the worst.
Conclusion: despite our Cessna 210’s absence of airframe de-ice, if we could find an ice-free path to climb above FL150 then the flight should be very doable.
Now, how could I find such ice-free climb path? The actual weather picture showed we may be able to fly the climb forward of or behind the band of weather. The FPL route was in the middle so a nogo. I was also quite light about 1000lbs short of MTOW with only 1POB and about 90USG fuel, so that was also part of the how.
I did not keep a picture of the full actual wx but this later Golze ADL picture less than 1 hr after take-off gives an idea:
For scale the total route is about 300NM. The weather band extended due South until 10NM North of Mallorca. If I could not find the route upwards there was no immediate safety threat since there was plenty of warm, clear air underneath to descend to, but I had decided that would mean an air turn back for the reasons explained above.
Fortunately ATC was OK to have me climb IFR into Class A on a N-NE heading “to avoid” where I should be ahead of the weather. The look out the window was grimmer to the West so we picked North East as we crossed the coastline
And, poorly extracted from therein, the ADL picture confirmed our plan should put us ahead of the worst wx.
As we entered cloud in the climb, performance was good in cruise climb and there was no ice. As we got to FL095, and about -3C a trace of ice started accreting on the leading edges, but the climb rate stayed a solid 700 fpm+ . Prop antiice was on and the climb continued in IMC until through FL110 and about -9C, when ATC requested whether we could turn westbound before approaching the TMA boundary, when a change from Palma to Barcelona control would be due. I guess they wanted to make sure we transferred while approaching the designated TMA crossover waypoint. Maybe there was one or two mm of ice on the airframe but performance did not budge and I had the expectation to exit the conditions in a couple more minutes’ climb anyway, so…
No1 I obliged and turned westwards.
Less than 30 secs later, the characteristic sound of rime ice accreting started and I knew it had not been such a good idea to change heading. The trace ice had quickly turned into light or perhaps worse, so I had to act. The frequency was busy and climb performance was still good, so I waited a minute until, by then through about FL130, I was asked to change frequency.
No2 I obliged and changed frequency
I could not get a word in edgewise on that one either and by now approaching FL140 as I was just about to change heading for later announcement, the airframe sound ceased , I knew icing had stopped, and as OAT’s descended beIow -13C, I continued the climb as previously cleared to FL180, announcing light icing between FL090 and FL130. Climb performance was maybe 100fpm less than before but by now 1/4" ice had accreted on the leading edges.
Since performance was still good, I did not see a reason to change plans and simply continued on to destination, exiting IMC shortly before reaching FL180 , between layers, and when ROC was still a healthy 500 fpm.
Cruise was some 5KTAS slower than expected but nothing serious, but at -16C and under an overcast, it would not sublimate off.
The rest of the flight should have been uneventful. The over and undercast started thinning approaching the mountains
until it was CAVOK on the other side, all just as depicted on the GRAMET.
As I descended, ice melted off below FL080 starting at the tips
I did some check on the autopilot and
No3 left the incorrect (bank-hold) setting vs HDG as vectored. THis meant over the next four minutes, heading slowly changed 40 degrees…while I concentrated on setting up nav and briefing the approach until, all of a sudden, I realized my mistake and corrected the heading, bummer! ATC did not notice or mention it despite the radar environment so I left it at that…
I did have to deal with a 40KT SE-erly gusty wind blowing down the long runway. There was no turbulence until below 3000ft on finals when moderate set in all the way until landing. I slowed down to 120KIAS to minimize turbulence and ATC complained of the low GS in the low 70’s, making final in the RNP approach a bit time consuming…but not much I could do as I continued the approach to the runway flanked by the huge Airbus final assembly buildings
I landed clean (other than gear) and long still finding myself taxying for an eternity at 60KIAS towards our assigned exit. As soon as I turned off I had to remember my controls positioning for taxying in strong winds, airplane moving more than I like to see, although control was still good.
All in all an interesting 1.7h flight that we can hopefully learn from:
No1 and No2 were unnecessary mistakes: maintaining N-NE-heading per my pre-self-briefed plan to remain East of the Wx until above icing levels should have been my priority and I should have advised ATC likewise.
No3 is a good reminder of the importance of keeping a good scan, even if in good VMC
OTOH, would I have been better off flying West (vs East) of the occluded front wx?
