MTBUR question

[red_moon]

[隱藏]
mean time between unscheduled removals, MTBUR
eq1)
MTBUR = (FHxnxN)/NR
FH = Flight hour per aircraft
n = Number of aircraft
N = Quantity of Units removed from aircraft
NR = Number of removals of item

2 units are installed in the aircraft

if one unit is inoperative, only one would be replaced
if both are inoperative, replace both at the same time


20 aircrafts
operate 10 hrs/day
20 items were replaced but 8 of them were replaced at the same time

how should i do it?

as i saw there is the other equation for MTBUR
Number of flight hours x units installed per aircraft
Number of unscheduled removals during that period
= MTBUR

i tried to use both but ans are not the same.......
the 2nd equation is easier for calculation but i was told to use the 1st one
please give me some advice for it...
thanks for ur reply

[Tarik El-Azzouzi]

I m not familiar with MTBUR calcaultation specific to aircrafts..But basically, to calcualte MTBUR, you should consider the total cumulative operation time (based on all units) and divide it by total cumulative number of unscheduled removals (based on all units).

I assume you are calculating this for a component or a subsystem in the aircraft, right? If yes, then you should find out how many of this particular component you are interested in exist in each aircraft. Let say that you have N aircrafts and in each aircraft, there are n units of that particular component. And let's say that each aircraft accumulated T hours. And you had to replace M number of units of that particular component you are interested in.
Then MTBUR = T x N x n / M