Climbing out of Biarritz on the ‘DONUS’ departure it was obvious this was going to be a bumpy flight. Towering CU reaching beyond our planned FL100 cruising route. We were in and out of cloud and in the tops we accumulated light rime which went as quickly as it accumulated in the ‘clear’ segments.
I was accompanying the owner to his holiday residence in Portimao (Algarve). He was in the left seat.
The Duchess was not de-iced and I was monitoring the accumulation carefully and it never became more than 2-3mm for the entire flight.
With approx 100nm to go we became solid IMC. The forecast had warned of embedded CBs and within minutes of becoming IMC we started to climb unintentionally at 700fpm. I warned ATC we were unable to maintain altitude and he responded simply saying ‘no reported traffic’.
We tightened our seatbelts, turned instrument lighting on and I checked MSA (4000ft amsl).
It then started to rain very heavily, in fact water started to ingress the cockpit! The radios started to ‘wail’ and the nav flags appeared on both VOR indicators and then the turbulence increased to quite an uncomfortable degree. I took control and soon after I saw a ‘hole’ all the way down to ‘terrain’-we spiralled down and levelled off at F070.
No GPS then (1989) and due to the terrain we were unable to pick up any navaids so flew southwards back onto our original track.
When I say ‘I took control’ it is pertinent to point out that the auto-pilot had disconnected in the turbulence!
It was reassuring to see the terrain however a) It did not look very attractive with rocks and peaks and b) it looked surprisingly nearby!
I stabilised on heading and re-engaged the auto-pilot and we both breathed a sigh of relief.
Suddenly, we burst out of the cloud into an amazing vista of blue sky and sunshine. Looking behind at the black CB we had just left I thought to myself nobody would fly into that!
We landed at Faro, cleared customs and continued to Portimao our ultimate destination.
Looking back, the sensible option would have been to divert to Seville or make a 180degree as soon as we encountered the ‘updraft’. It is a classic warning (I now know!) however the destination forecast was CAVOK and glimpses of blue sky and sunshine were compelling me to continue.
We made the trip several times after that without encountering any ‘serious’ weather and the owner progressed onto a PA34, PA31 and Kingair although he now routinely does the trip in his Seneca V. We still fly together occasionally and remind ourselves of our episode in the Duchess!
