Saturday, 23 November 2013

Twice as nice

As you can see, we have been cursed with a spell of typical English weather that has temporarily halted all flying. I thought I'd take the brief respite to write about our latest challenge — flying the twin engine Piper Seneca.

Compared to the small single engine planes we have flown to date, the Seneca is a bit of a monster. It has nearly three times the power of the Warrior and flies 50% faster. There is a lot more equipment on board, like de-ice systems and autopilots and though a lot of it does not work, you at least get the feel of a 'real' aeroplane. I could — in theory — fly home in one of these.

You couldn't call our battered old examples glamorous or smart, but with a bit of imagination and a bit of a squint you can picture a couple of wealthy executives in the back being whisked off to their next meeting by, well, one of us. No longer are we just learning to fly ourselves around, suddenly there is the reminder that we are training as professional pilots. It won't be long before we will be piloting large and very expensive aircraft with paying passengers in the back. Scary.

Buddy at the controls looking forward to his first flight
I had been somewhat nervous about the additional weight, speed and complexity of the Seneca, but after extensive briefing and memorising lots of new check lists I finally got to try it out this week. I was first out of our group, so it was up at 4.30am to check in and complete the pre-flight checks.

Once we were all strapped in I took my time running through the unfamiliar before take-off checks before I finally got to say for the first time "starting no. 1 engine". Taxiing was tricky, with the rudder pedals connected to the nose wheel via springs only, and my progress to the run-up area was cautious and less than elegant.

The power checks in the run-up area revealed the first, and really only tricky part of operating the Seneca — the twin throttles. They are quite sensitive and moving them together while keeping the same power coming from each engine is far from easy. Unlike the Warrior, you can't just shove them to full either. The turbochargers will kick in too strong and "overboost" the engine, damaging it.

Onto the runway and line up, two quick check lists then it was time to release the brakes and open the throttles. The acceleration was rapid, much more so when the turbos kicked in. Between the vague nose wheel steering and inability to keep the throttles balanced my take off roll meandered all over the place, but almost before I had time to sort it out we were doing 77 knots and it was time to fly.

As soon as we were in the air, I could feel how stable the plane was and just how rapidly it climbed. No time to think though, there was the after take-off check list to get done before turning at 500 feet — which takes all of 35 seconds in this plane.

More knobs, buttons, levers and dials than you could shake a stick at.
The instructor was certainly right when he said it loves to climb. Levelling off was a challenge at first, each time I thought I had the plane nicely trimmed out at the right speed I would look away for a moment then find myself 100 foot higher. I'm not sure if it is turbo lag or something, but it really takes a while to set get it properly set up.

Once it was settled down it flew beautifully with minimal input from me. It was far less affected by rough air or thermals, and felt like it would hold its height and heading until it ran clean out of fuel. This would not take long, as it drinks about 22 gallons of avgas per hour. Not one for the environmentalists!

It took a while to get used to the constant speed props. No longer is the power set by choosing a engine speed, instead we set the pressure of the fuel/air going into the engine. The plane will automatically twist the propeller blades to keep the engines turning at the same rate, regardless of your speed through the air or the amount of power set. We are used to listening to the engine note for speed changes, so it is disconcerting to hear the same drone all the time. We also have to carefully tune the engine speeds to avoid irritating 'beat' frequencies.

We spent some time getting used to the plane and doing general handling practice, then it was off to Goodyear to fly some circuits and landings. The big moment! Rumours abound about how difficult it is to land, and how it will just 'fall out of the sky' onto the tarmac before you are ready.

Perhaps it was simply the quality of the instruction, but I didn't have a problem. Certainly the control forces are higher than we are used to — it's definitely a two-handed job to flare — but much to my relief I was able to set it down quite nicely each time.

We were doing "touch and go" landings, so the next part happened very fast. There was just time to retract the flaps and fiddle about trying open the throttles evenly and stay more or less straight when we were back to rotation speed and it was time to fly again. Around we went, another five circuits, each time I got a bit better with the check lists, but I never quite got on top of the touch-and-go checks.

Then it was time to literally fly home. The fun parts of having so much speed on tap is beating all those Warriors back to base!

Asymmetric flight

One of the nice things about the twin is its symmetry. The single engine aeroplane may look symmetrical, but its engine and propeller only rotate in one direction. This gives rise to all sorts of complicated effects that conspire to pull you off course to the left, and constantly varying amounts of right rudder are required to keep it straight.

On the Seneca, the engines rotate in opposite directions and everything is nicely balanced. You hardly need to trouble the rudder at all. Provided, that is, both engines are running.

Err.. shouldn't that propeller be, er, going around?
But barely had we got to grips flying with two engines when it was time to fly it one just one.

Pretty much all twin-engine planes can fly on a single engine, though with reduced performance. This is great because it means an engine failure does not necessitate an immediate landing, and you are allowed to fly out of range of suitable landing areas.

So much for the theory, actually flying with one engine is quite an experience. When an engine fails, the plane will veer off course, start turning towards to the dead engine, lose around three quarters of its power and descend.

Once back under control, the rudder forces to keep the plane straight can be huge, literally all my strength was needed when flying slowly at high power (think take off!).

The worst time an engine can fail is of course just after take off, so this is what we practice. We will get a few hundred feet in the air when suddenly the plane will lurch off one way or another — the pesky instructor has closed one of the throttles and covered them up so you can't see which.

We then have to control the plane, identify the failed engine, run through a whole load of extra check lists and fly the circuit with one leg jammed on the rudder. Just before the landing the instructor will return control of the 'dead' throttle for landing.

The scary part in a real engine failure is called the committal altitude. Once you have the landing gear down and the full flaps out, the single remaining engine simply does not have enough power to make you climb. You HAVE to land. There is no going around and trying again!

That's all for now. We are enjoying flying the twin but the pressure is really on. If all goes to plan, in around  two weeks I will be a qualified commercial pilot with a multi engine rating. Keep everything crossed for me!

2828L - the first twin engine plane I have flown.


  1. I found your blog just now after googling around while reading up on the Future Pilot Programme 2014. Just wanted to say thanks for writing, it's really interesting! I'm going to work my through all your posts. Best of luck for your qualification and the remainder of the programme.

  2. Nerve wracking stuff again! Fingers crossed for the next two weeks!


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