Failure

I must describe about the shameful affair happened a few days ago, my R/C training airplane fell down and destroyed a bit and now she is under repairing procedure, about fuselage almost completed, about the main wing troublesome a little is not yet. Then, why such kind of Mayday occurred on earth, tried by a long trained pilot(over 50 years experience), with the power source well adjusted and in good condition, long established mechanical controlling(over 100 flights) and with the best reliable Radio and servos?
The accident was caused by nothing but negligence and laziness by myself, running short of battery power supply, I didn't charge after the flights.
No control condition was the result at all, how come!-----Just loosening affections!
In addition, another unexpected affair happened on "Begin the Begin" no controlling the rudder because of wire linkage falling down on the left side, just omitted I lockout rubber tube there.
However carefully I may pay attention and check deeply, accident happens through any loophole? The reason why I cannot recognize it is just because of age(Dull sensitivity)?
As I could know OS 46LA motor is suitable for YOSHIOKA Pegasus 40, I would like to try ENYA 40X motor as the next power source, I happened to have 2 of 40X at hand, new supply parts, 2 sets of piston & cylinder, a cylinder head, a G type carburetor and a piston pin came to me as some residual junk part, so I made up my mind to complete them gathering missing parts. Now have I no missing parts at all but 2 completed 40X instead.