A component with a Time Between Overhaul (TBO) of 350 hours may be removed at how many hours?

A component with a Time Between Overhaul (TBO) of 350 hours may be removed at how many hours?

• A. 315 hours
• B. 385 hours
• C. 315 / 385 hours (Tolerance factor plus or minus 10%)
• D. 350 hours

Answer: (C)

Time Between Overhaul uses a tolerance to account for slight variations in manufacturing and operation. A +/-10% tolerance means you can remove the part anywhere within 10% below or above the nominal TBO. For a TBO of 350 hours, 10% is 35 hours. So the allowable removal window is from 350 - 35 to 350 + 35, i.e., 315 to 385 hours. The correct interpretation is the range, not a single fixed hour, since the tolerance defines an interval in which removal is permissible. The other options represent only one end or a single moment, or miss the idea of the allowable range created by the tolerance.

Time Between Overhaul uses a tolerance to account for slight variations in manufacturing and operation. A +/-10% tolerance means you can remove the part anywhere within 10% below or above the nominal TBO.

For a TBO of 350 hours, 10% is 35 hours. So the allowable removal window is from 350 - 35 to 350 + 35, i.e., 315 to 385 hours. The correct interpretation is the range, not a single fixed hour, since the tolerance defines an interval in which removal is permissible.

The other options represent only one end or a single moment, or miss the idea of the allowable range created by the tolerance.