I had flown this route from Southend to Cannes six times previously and it had been ‘routine’ flying in the airway system following VOR Beacons DVR CMB CTL TRO DIJ LSE MTL AMFOU LUC STP and then usually ‘cancel IFR’ at St Tropez and around the coast to Cannes.
This was September and a Cold Front was sitting just west of the Rhone Valley. An early start was normal for me as later in the day it could get quite ‘bumpy’ and during Summer months the Thunderstorms developed later in the day.
By Troyes I was solid IFR with OAT -8C at FL110 and light rime icing visible on leading edges. The PA34 has leading edge boots, heated props and heated windshield panel. Now, 2hrs into the 4hr 30min flight, the auto-pilot was working well and I was considering cutting the corner at Montelimar. This would mean a climb to FL120 which, although an inappropriate level, Marsaille usually allowed. By the time I passed Lyon the icing was requiring intermittent operation of the boots. I had Lyon and Avignon available as diversions and had the approach plates ready.
Lyon offered me “Direct AMFOU” which I accepted immediately and requested FL120 which they gave me and I turned left towards AMFOU or at least a guesstimate as no GPS in those days! It would mean flying over higher terrain but would reduce my flight time by at least 15mins.
The vibration from the left engine took me by surprise. These 6cyl turbocharged Continentals were usually as smooth as silk. It got worse, much worse and then I remembered Louise (that’s Louise Sacchi and her book ‘Ocean Flying’) and how she encountered prop icing and varied the prop RPM to shake it off! I exercised the prop gently then a little more; there was a ‘crack’ as some ice hit the fuselage and it was gone. All went well for the rest of the flight and during descent towards St Tropez I entered CAVOK conditions and landed safely at Cannes.
I got out the aircraft having left the prop heat on. Two boots on the left prop were warm but the remaining boot was cold… I secured everything and went and had a beer!
On reflection, I realised I had exposed myself to greater risk. I had already accumulated ice and nevertheless accepted a ‘short cut’ which reduced my terrain separation dramatically for the sake of 15mins and even if I had not had the prop icing issue, I had given away the safety margin. The failure of the heated boot on the prop highlighted the importance of having a backup plan.
My hair was ginger until I was about 40. It then turned almost white…!