Ed_Wischmeyer
Well Known Member
?Approach, experimental XYZ, pan, pan.? That got their attention!
I?d used mayday two or three times in the past, but this was the first time using pan. I was flying with a friend, and when he gave me the controls back in the RV-9A after doing a turn, the stick was really heavy. The elevator trim indicator showed way, way nose down ? uncommanded. And the elevator trim switch was ineffective. After talking it over with my friend, also a very experienced CFI, we decided this was an appropriate PAN situation and going home right away was the best course.
We were about 8 minutes out, about 120 knots, and what to do? ATC offered closer airports, but home base seemed pretty doable. But it took a LOT of pull on the stick.
The first decision was that I had him fly so I wouldn?t be landing an out of trim airplane with really tired arms.
The second decision was what speed to fly. With nose down trim, flying faster would probably have meant less stick force, but the decision I made was that the plane was controllable as it was, so let?s not screw with anything we don?t have to. We didn?t discuss this, however, but he didn?t suggest anything different. We did discuss that this would be a no flap landing to avoid any more nose down pitching tendency.
What was a bit of a surprise to me was that when I wasn?t concentrating on a two handed pull on the stick, I suddenly had a lot more relaxed brain cycles to deal with the situation. On my plane, the autopilot pitch servo changes the speed of the electric pitch trim, depending on airspeed. With the autopilot pitch servo powered off, the elevator trim switch goes directly to the trim servo. Tried that and it restored normal trim function, so I told approach control that we had resolved the situation. But I did not explicitly cancel the pan.
Meanwhile, ATC had apparently escalated the PAN to a Mayday for us as we found out when tower referred to us as the emergency aircraft. I told them that we had canceled the emergency, we landed, put the plane away, debriefed and took a break.
The decisions made:
* Go back to the airport right away;
* Pass up the closer airports as the plane was flyable and we had two pilots. An okay decision, maybe not the best. There was an Army air field we flew over with a long runway, but the situation was resolved by then. A short runway would not have been a good choice. But if I had been flying solo way out in the boonies, I might have chosen to land it wherever before my arms gave out;
* Discuss the situation with the other pilot;
* Declare a Pan;
* Get the other pilot to fly the plane for a bit.
But there were good decisions made in advance:
* The autopilot servos were on a circuit breaker switch and were easy to find as they were at the end of that group of switches. I didn?t have to read any label to know which switch to flip;
* I?d spent lots of time learning the details of this installation and how all the parts interconnected and worked. I knew everything that pertained to the elevator trim without having to look anything up;
When we upgraded the avionics, the elevator trim stayed on its own circuit breaker in the middle of a row, supplying power to the electric trim switch. It?s easy enough to find, but not nearly as easy as the autopilot servos. If I were designing a panel from scratch, I?d have disconnect switches all next to each other as circuit breaker toggle switches.
The last step was to call the tower and thank them for good handling. A five second call, but they appreciated it. And no paperwork to fill out.
I?d used mayday two or three times in the past, but this was the first time using pan. I was flying with a friend, and when he gave me the controls back in the RV-9A after doing a turn, the stick was really heavy. The elevator trim indicator showed way, way nose down ? uncommanded. And the elevator trim switch was ineffective. After talking it over with my friend, also a very experienced CFI, we decided this was an appropriate PAN situation and going home right away was the best course.
We were about 8 minutes out, about 120 knots, and what to do? ATC offered closer airports, but home base seemed pretty doable. But it took a LOT of pull on the stick.
The first decision was that I had him fly so I wouldn?t be landing an out of trim airplane with really tired arms.
The second decision was what speed to fly. With nose down trim, flying faster would probably have meant less stick force, but the decision I made was that the plane was controllable as it was, so let?s not screw with anything we don?t have to. We didn?t discuss this, however, but he didn?t suggest anything different. We did discuss that this would be a no flap landing to avoid any more nose down pitching tendency.
What was a bit of a surprise to me was that when I wasn?t concentrating on a two handed pull on the stick, I suddenly had a lot more relaxed brain cycles to deal with the situation. On my plane, the autopilot pitch servo changes the speed of the electric pitch trim, depending on airspeed. With the autopilot pitch servo powered off, the elevator trim switch goes directly to the trim servo. Tried that and it restored normal trim function, so I told approach control that we had resolved the situation. But I did not explicitly cancel the pan.
Meanwhile, ATC had apparently escalated the PAN to a Mayday for us as we found out when tower referred to us as the emergency aircraft. I told them that we had canceled the emergency, we landed, put the plane away, debriefed and took a break.
The decisions made:
* Go back to the airport right away;
* Pass up the closer airports as the plane was flyable and we had two pilots. An okay decision, maybe not the best. There was an Army air field we flew over with a long runway, but the situation was resolved by then. A short runway would not have been a good choice. But if I had been flying solo way out in the boonies, I might have chosen to land it wherever before my arms gave out;
* Discuss the situation with the other pilot;
* Declare a Pan;
* Get the other pilot to fly the plane for a bit.
But there were good decisions made in advance:
* The autopilot servos were on a circuit breaker switch and were easy to find as they were at the end of that group of switches. I didn?t have to read any label to know which switch to flip;
* I?d spent lots of time learning the details of this installation and how all the parts interconnected and worked. I knew everything that pertained to the elevator trim without having to look anything up;
When we upgraded the avionics, the elevator trim stayed on its own circuit breaker in the middle of a row, supplying power to the electric trim switch. It?s easy enough to find, but not nearly as easy as the autopilot servos. If I were designing a panel from scratch, I?d have disconnect switches all next to each other as circuit breaker toggle switches.
The last step was to call the tower and thank them for good handling. A five second call, but they appreciated it. And no paperwork to fill out.