Last Saturday, I drove two hours to an airport in southern Germany, to meet Dan and go flying in the Alps with a DA40 TDI together. Dan is a reader of this blog and asked me if I could act as safety pilot as he has not a lot of experience flying the Alps. How could I say no ?

The plan was to fly down to Sion via the Alps. This implied a flight plan and customs clearance as Switzerland is still not part of the European Union. We decided to meet at an airport with customs located a few minutes north of his home base. The drive was fine, with good weather and low traffic, I enjoyed the speed unlimited German Autobahn a lot. This was the only part going as planned.

I started to wait close to the runway, monitoring the airport’s frequency on my handheld radio. Approximately 45 minutes (sic) after Dan’s planned landing time, the radio clicked but there was no modulation. Only a carrier. The controller answered with a clearance to join downwind, using the call-sign Dan gave me the day before. Was my radio having problems ? This went the same until landing, the controller repeating that Dan’s calls were unreadable. Uhum.

After landing we met and shook hands, and talked about this radio problem on our way to the tower. I was wondering how the controller picked-up the call-sign. The mistery was rapidly solved: the departure airport noticed the problem and called here. The controller also told us that we had to request customs service… with one hour of notice. Oops. As we did not wanted to make the whole flight using only a handheld radio, we decided to fix this problem first and establish a plan after that. We went back to the aircraft, and the radio worked fine at first try.

Back to the tower, we decided to go for an alpine flight without landing. This avoided the need for customs clearance, but a flight plan had to be filed because of the border crossing. We defined a nice route and filed it before waiting for the 30 minutes notice time to elapse. We boarded the aircraft, discussed about procedures, about flying with another pilot, how to share workload, and it was time to start…

But not with a “DOORS” warning shining on the alarm panel. It’s rather common on DA40s to leave the read door open, but it was not the case. We opened it and closed it again. Then the front canopy. No change. I disembarked, walked around and tried again. The door was obviously closed. May be a wrong contact. The next attempt was the good one, the alarm vanished. Here we go again.

Engine start-up was fine, as usual with TDI engines. We taxied to the run-up point. The annunciator panel went black after the engine test. Looks good. Shortly after, we got an “ENGINE” indication. The engine indicators did not show any abnormal condition. may be a parameter did briefly exceed a limit. Acknowledge, no worries. This is the magic of electronic engine monitoring: no small deviation goes unnoticed.

The alarm appeared again a bit later… during the take-off roll. I noticed it and had a quick look at the engine instruments. Again, everything was in the green. We were just at rotation speed and I decided not to intervene. I did not know if Dan noticed it or not but it was not the moment to discuss it. The aircraft was climbing normally. Passing safety altitude, we retracted the flaps and Dan acknowledged the alarm.

We stopped climb rapidly because of airspace restrictions. Dan worked the radio to organize our transit through Basle airport’s airpsace. Just after that, the “ENGINE” alarm popped up again. I looked at the engine instruments in front of me again, and this time I saw the “Water Level” light blinking. Blinking ? Yes. This light is supposed to turn on when the level of engine coolant is too low. It was now blinking intermittently. All temperatures were in the normal range. Was the level just at the limit, or was there a problem with the probe ?

I already had such alarms with other Thielert equipped aircraft, usually during the climb. The probe is located on top of the engine and if the coolant level is close to the limit, the alarm sometimes comes. But we were not in climb. And when heading towards the Alps, an intermittent engine indication is the last thing you want. We were abeam Dan’s home-base and he made the decision to land there. It was not a good day to fly.

Aborting a long expected flight, or not taking off, all because of an intermittent, probably spurious alarm is not easy. I congratulated him on that after landing, and even if he looked a bit frustrated, we agreed that it was the sole sensible thing to do.

By the end of the day, it was nice to meet Dan and build some experience together. He probably learned more about decision making during this very short flight than if we had been flying in the Alps as planned. I ensured him that it was no problem for me, and that the Alps will still be there next time we’ll plan a flight together.