Tuesday, September 24, 2013

Common Yet Unexplained Accidents

Terrafugia TransitionTerrafugia TransitionSometimes it’s hard to figure out what to write about. This is one of those times. However, there has been something nagging at the back of my head for some time. How come I read about so many seemingly trivial accidents/mishaps on takeoff and landing on the FAA accident site?* For example: landed and went into the trees, on landing flipped over, on taxi struck a parked vehicle or airplane, on take-off from a private field crashed into a shed etc. I counted twenty-one of these events in just two days plus a weekend. Yeah, I know weekend warriors etc. For example on 9/21/13 two events were listed one after the other. Both struck a pole while taxiing. Just one day prior again two listed one after the other: aircraft left the side of the runway and the other aircraft left the side of the runway into a ditch. How does one manage to do all this?

In my 40 plus years of flying I once dinged the wing tip of another plane while taxiing and cracked the lens of a wing tip light of another high wing Cessna. Cheap to repair and not really a big thing, although at the time I was horrified on seeing what I had done.

So I have to wonder whether pilots are really paying attention to what they are doing. Could they be looking at something non-essential such as a hand held device? Or maybe texting a friend that they are running behind and not to worry if they are a bit late.

Another thing I puzzle over is why I keep reading about nose wheels failing on landing. The only reason I can come up with is that maybe pilots aren’t flaring sufficiently to hold off the plane and land on the mains. In other words, landing too hot and literally forcing the plane on the ground when there is still some flying speed left. Ok, maybe there is an occasional bearing failure or some other mechanical problem causing a failure, but I believe that to be rather rare.

If you find that you are having some of the problems I have described above maybe you should try flying the”Terrafugia**, A Transition Roadable Aircraft”. Good luck in staying safe and on the tarmac.

Sunday, September 1, 2013

After Reading That There Have Been 96 Accidents In Various Models Of The Rockwell Commander 690....

After reading * that there have been 96 accidents  in various models of the Rockwell Commander 690 since May 1969, I have gained a new respect for the level of piloting skill that is required to fly one. I spent time reviewing some articles concerned with the piloting of twin turboprops and turboprops in general.  I now appreciate that they are really considerably more complex than their smaller conventionally powered cousins e.g. the Beech Barons, Cessna 300 and 400 series etc.

All one has to do is to look at the pictures of the cockpits, with special attention to the engine and prop controls, as well as to the engine instrument gauges to gain a new perspective. The fixed shaft Garrett engines that power the 690 have four engine gauges per engine. While the Pratt & Whitney PT-6 which powers the King Air has six gauges per engine. That’s a lot to pay attention to. The main time the pilot must watch these gauges is at start-up so as not to exceed a critical engine temperature. Failure to do this might result in a Hot Start, with resultant engine damage if the engine is not immediately shut down. Anyway, this is just to make us aware that the turboprop engine requires more out of the pilot as compared to the conventional piston powered type engine.

The planes themselves are heavier than their piston counterparts such as the C-310, Pa-31 or B-58 by several thousand pounds. Critical stall speeds are higher. For example the stall speed with full flaps and gear (dirty) is 75 kn, while in a Pa-31 Navajo, a plane I used to fly (and love), stall speed dirty is 65 Kn. Big difference, especially for the non-professional. OK, now maybe you see where I am heading with this. In order to feel competent when flying any of the planes I used fly, whether Pa-31 or a Bonanza, I needed to fly a lot, frequently as often as once a week or more. To think that I could comfortably handle the complexities of a twin turboprop, as a non-professional on a casual basis is just out of the question.

So, in my opinion, the pilots of the recently crashed Aero Commanders  had a lot to contend with.    Maybe when everything is just fine, both engines purring along, weather not too bad, field in sight and cleared to land, all is OK. But as in New Haven, things can get a bit dicey, quickly. Weather getting bad, a sudden runway change and too much to deal with in a demanding plane can be overwhelming. The other crash occurred during recurrent training at 12 to 15 thousand feet. It isn’t that hard to enter a single engine stall when the nose of a heavy plane is pulled up a bit too far with one engine idled. But it is almost impossible to escape a flat spin when one is accidentally entered. These usually end with a fatal crash. That is one scenario I suspect happened as discussed in my article of July 5, 2013 in Operationsafeflight.blogspot.com.  

In summary. The twin turboprop is considerably more difficult to fly than the smaller conventionally powered twins. That means piloting a turboprop requires considerably more skill and training than some may believe. The statistics are a bit scary as are the recent number of crashes.  Future turbo pilots beware and prepare.