Tuesday, November 22, 2011

Partial Engine Failure on a Flight to Aberdeen

I received a message from a fellow multi engine group member asking if I was free to share a trip to Aberdeen in the Seneca. This sounded like an interesting prospect and, following a couple of conversations with the member, Bernard, we were set to go on Saturday November 12th. Because daylight is limited this time of year, we wanted to get away early so as to be sure to be back before dark as I am unable to hold a night qualification. Bernard had a business meeting near Aberdeen airport so he would shoot off to that while I prepared the aircraft for the return flight to Blackpool.

Because fuelling the aircraft can be time consuming, I wanted to sort that out on Friday afternoon, ensuring a speedy departure on the Saturday morning. I got a room at a nearby hotel for the Friday night and turned up at lunch time to sort the fuel. However, the plane was in maintenance having a new ADF fitted and the seats were out. But the engineers said they’d fuel it for me later so I’d be ready as planned.

Saturday morning I checked the weather on my iphone and filed a flight plan via EuroFPL for off block at 0915. Bernard joined me at Blackpool just after 8am and we left the apron bang on time. The route was simple: climb to FL70 en-route MARGO, then direct Aberdeen, a distance of 208 nautical miles. The weather was good and we would have a healthy tail wind on the journey up. We taxied the short distance to A3 for runway 10 and were soon turning left and climbing away. We levelled at FL70 and the route ahead looked fairly clear. I saw Carlisle pass beneath my left hand window and felt very happy at our groundspeed of 195kts, or 225mph. Not bad at all. We would be at Aberdeen for 10:35am. Or so we thought!

As we approached some cloud I checked all the engine gauges and thought to myself, “leave the power and trim well alone”. We went into the clouds but were soon out after a couple of minutes, if that. I am in the habit of constantly sweeping my eyes over the instruments and my eye caught the mis-match between the left and right engine manifold pressure shortly after becoming visual again. At first I thought perhaps I had inadvertently pulled the power back, but no, the throttles were matched and the engine did not respond to further throttle movements. I could reduce power but not increase it. The temperatures and pressures on both engines were all in the green and symmetrical; the magnetos and fuel selectors were all on and I could not find anything wrong. I tried alternate air but that made no difference. Both propellors were still turning at 2400rpm. Bernard looked to see if there were any oil leaks or fire in the engine but there was not. There was only a small amount of yaw and control was not a problem.

We clearly had an unknown problem with the right engine so I decided we would turn around and land at Carlisle, some 25 miles south of our current position. I advised Scottish ATC of my intentions and turned the aircraft to the south. Scottish helpfully got me the Carlisle weather and I started a descent towards our new destination. I made contact with Carlisle who had been advised of our problem and we were told we could land on any runway.

Bernard, who was still watching the right engine, then informed me there was smoke coming from it! I asked him if he could see any fire and he said no. I can’t remember how far from landing we were at this stage, but I told Carlisle that we had smoke coming from the engine. As there was no fire, I decided to keep the engine running as it was producing power and all gauges were in the green. Shutting it down would have made control more difficult and I wanted the power it was producing. Had flames been seen I would have had to close it down.

We spotted the airfield and positioned on final for runway 19. I had to make this a good approach as a go around was not a prospect I fancied with a sick engine. The wind was on the nose and there was a landing distance of over 800 metres. I dropped the undercarriage late and selected flap progressively as we closed on the runway. Mixture fully rich, props fine and three greens, it was my best ever landing in a Seneca! The fire truck followed us down the runway and back to the apron. With engines off, the fire guys came over and checked us out and decided no further action was needed. There was oil dripping onto the apron from the cowl flap. A drip tray was placed to protect the surface of the apron and we all looked around to see if there was any damage to the engine. No damage was evident so far. Bernard whipped off the engine cowlings and we tried to see where the oil was coming from. It was hard to tell but a dip of the oil sump showed we had lost around two quarts since the power loss.

The firemen said they could clearly see us trailing smoke on the approach and were a little concerned. However, all ended well, apart from not getting to Aberdeen and being stuck at Carlisle. A phone call to base and soon two guys were on the way up to rescue us in a Cirrus SR20 and an engineer soon followed in a C172. The Cirrus took us via Deans Cross VOR then direct to Blackpool at 5000ft, much better than a hire car or public transport. Later that evening I heard a suspected cracked cylinder may be the reason for our problem.


Thumbs down at Carlisle!

The offending engine

Our thanks go to the guys who flew up to rescue us and also to the chap from Carlisle who offered to drive us home if we were still stuck at his knock off time of 5pm.

I have been flying for nearly thirty years and this was my very first engine failure. I hope these things do not come in threes!

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