For each run of propeller input the data in column of plane flight time day by day. Against each day. Arrangement of data can be shown as below
Plane 1 Plane2 ..........................palne 10
->Now add flight time per day of each and every plane separately. This will give total hours flown this month for each airplane.
-> Average hours flown for all airplanes = sum of total hours flown by all planes/number of plane
=sum of total hours flown by all planes/10
-> By representing the data of total hours flown per month as a histogram and drawing a line for number of hours flown as cut-off line for minimum number of hours flown by a plane. All planes whose histogram crosses the cut-off hours will require maintainence.
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