Where there is a doubt, the CD has the power to rule whether the primary plane is "unable" to fly again,. One case: During my first flight, the needle valve somehow broke off, causing an engine stop during the flight. I did not have a replacement engine, but I had a back up plane. The CD allowed my use of the second plane.
Of course. The rule is designed to give people a break if something unfortunate happens. It is a rule only to prevent people trying to process multiple models as a competition strategy, causing all sorts of headaches for the CD.
For everyone - here is the deal with the rules. All of these "conduct of the contest" type rules exist only to prevent *abuse*, not to try to catch anyone on anything.
A perfect example is the 3 minutes - yes, by rule, you have 3 minutes after the last competitor has left the circle to signal for start. But, I can count on the fingers of one hand how many times someone has been put "on the clock" over this, and in those cases, only when it appeared that the competitor was trying to abuse it for competitive advantage. If someone is having a problem, there is *extreme tolerance* and only when it becomes a real problem is anyone informed that "you are on the clock".
Same with 'attempts', same with the "wingover makes the pattern official" (as opposed to "when the model leaves the ground" or "when you signal for start"), and a myriad of other rules. Things that bear on the score directly, we follow to the letter, but the rest are there to cover outlandish conditions and to give everyone a chance without giving them a way to abuse the rules to get an advantage.
No one is sitting there trying to "catch" anyone on the rules. You should know them and understand them, but there aren't people sitting around looking for reasons to DQ your or ding you on something that doesn't really matter. The *only* place these discussions happen is on-line, where it is made to seem like there are a bunch of people staring at you trying to catch you on minor infractions. It just doesn't work that way, unless you are completely clueless or trying to get a leg up on your competitors using technicalities, it doesn't happen.
Brett
p.s. I would also add, even when it might be legal, it is generally frowed upon to use rules tactically - like the "dead battery trick", that is, taking an attempt using a "dead battery", to try to delay the flight to get better air. Legal, no one is able to tell if it was a genuine failure to start or a tactical attempt, but people *will* notice and do it too often and you *will* get a bad reputation. Or any other tactic, for that matter.
Apropos of this thread, there are a (mercifully) few people sitting on the sidelines studying the rules like they were the Da Vinci code, thinking up various tricks to pull to try to make it hard for people - Peabody being one of the most egregious. You can see the result, Peabody is held in utter contempt by almost everyone who has been around long enough to have heard of him. He isn't ashamed of it, he used to hand out business cards proclaiming himself the "Antichrist of Stunt". People like him get shuffled to the side pretty quick, because reputation is *almost the sole valuable thing you get from stunt*.
Point being, these silly tactical stunts almost always backfire in one way or another - it might work the day you do it, but in the long term it works against you because you get identified as someone who *doesn't get it*.