Now, with the unbalanced situation
reported, the next step is to measure the severity
of the unbalance. For
the helicopter, the use of specialized equipment like Chadwick or RADS will give the mechanic a clock angle or position and the amplitude or intensity of the unbalance measured in inches per second (IPS). Unfortunately, there isn’t any specialized equipment you can hook up to a safety program to measure its unbalance. However, there are established tracking methods that measure the effectiveness or “amplitude” of the safety program. Just as with IPS, if a safety program’s total recordable incidence rate (TRIR) is high, this indicates a problem (unbalance) with the program. Still, it does not pinpoint its location or position relevant to the whole program.
FIXING (AND CREATING NEW) PROBLEMS
After several ground runs, the mechanic has enough information to correct the balance chart clock and make balance weight adjustments to the aircraft. However, what if on the third run the chart called for a 10-gram adjustment, but the actual move line crossed through
the chart’s zero bull’s-eye and relocated the unbalance position to a new clock angle? An experienced mechanic knows that every aircraft and vibration have their own unique sensitivities that require minor tweaks to established procedure. With a simple 50 percent reduction in the weight adjustment, the mechanic brings the unbalance situation back into manufacturer’s tolerances. The problem is solved. Now, here is where
our
comparison comes together. If a safety program can only measure the amplitude, and not the clock angle, of its unbalance, then it is destined to wobble around with some good years and some bad years. It’s like trying to balance your ceiling fan by
rotorcraftpro.com 53
taping pennies to the blades. You get real close, until the tape breaks launching a penny through a window. This leaves you with the same unbalanced fan and a new problem: a broken window.
But the most important point beyond
Page 1 |
Page 2 |
Page 3 |
Page 4 |
Page 5 |
Page 6 |
Page 7 |
Page 8 |
Page 9 |
Page 10 |
Page 11 |
Page 12 |
Page 13 |
Page 14 |
Page 15 |
Page 16 |
Page 17 |
Page 18 |
Page 19 |
Page 20 |
Page 21 |
Page 22 |
Page 23 |
Page 24 |
Page 25 |
Page 26 |
Page 27 |
Page 28 |
Page 29 |
Page 30 |
Page 31 |
Page 32 |
Page 33 |
Page 34 |
Page 35 |
Page 36 |
Page 37 |
Page 38 |
Page 39 |
Page 40 |
Page 41 |
Page 42 |
Page 43 |
Page 44 |
Page 45 |
Page 46 |
Page 47 |
Page 48 |
Page 49 |
Page 50 |
Page 51 |
Page 52 |
Page 53 |
Page 54 |
Page 55 |
Page 56 |
Page 57 |
Page 58 |
Page 59 |
Page 60 |
Page 61 |
Page 62 |
Page 63 |
Page 64 |
Page 65 |
Page 66 |
Page 67 |
Page 68
