Sunday, May 6, 2007

Comment and answer

I had this interesting comment as an answer to the "Trust the FADEC... but monitor it"

"Hi, yesterday a plane crashed into a bay in Flensburg - north Germany, and 4 people died. If the press ist right it was the DA40 with the Thielert-Diesel from a sports clup in Flensburg. So I googled the word "blackbox" because the press said "the blackbox was found" and i hadn't heard of blackboxes in single piston planes before. It is disturbing to hear from you, that the powersetting of the FEDEC seems to have a mind on it's own. Just speculating: What if you do sightseeing - slightly slow and low and heavy - and the powersetting changes just a bit - while you are talking to passengers - would you realize the loss of speed early enough?"

So my three answers to that. First all my sympathy goes to the familly and friends of all the people touched by this tragedy.

As an attentive pilot, you will notice any power change by noise change. I fly with a Bose X headset (thanks Santa...), but I still feel any power change, except may be very slight one, but such changes won't have impact. Even if you don't notice it, you will loose speed, and the stall warning will manifest itself quite early (see the previous post), and the stick will become less strong, and this should help you to notice the approach to stall.

Second part is that low and slow is never a good combination, so it depends how you define them. Anyway JAR OPS requires a minimum of 500ft AGL (more over crowded areas), and despite its nice stall characteristics, flying close to stall speed is never a good idea. This kind of problems can happen with any engine, be it FADEC equipped or not. You could have to manage a capricious mag, a fuel line problem leading to starvation, or fuel contamination on any plane. If you want time to react or more time to find a landing spot, slow and low is not a good option.

If your passengers want to see a particular spot (let me gues... their house ?) just circle it instead of flying slow.

Thanks for the comment anyway, they're always welcome.