en:wear_limits

Wear limits for a major overhaul and repair When does a part need to be replaced during a repair or overhaul?

The decision is to be made according to the following table.
This means that when repairing an engine that has run 520 hours, a part that has 62% wear according to the formula must be replaced.

TSN [h] (Time Since New)		max. permissible wear for repair [%]
from	to	TBO 1200	TBO 1500	TBO 2000
0	50	6	4	4
51	100	14	12	12
101	150	24	18	18
151	200	30	24	24
201	250	36	30	30
251	300	44	36	36
301	350	50	42	42
351	400	54	46	46
401	450	60	52	52
451	500	64	56	56
501	550	68	60	60
551	600	72	62	62
601	700	76	68	67
701	800	82	73	72
801	900	87	78	76
901	1000	91	82	80
1001	1100	95	87	83
1101	1200	100	90	87
1201	1300		93	90
1301	1400		96	92
1401	1500		100	94
1501	1600			96
1601	1700			98
1701	1800			98
1801	1900			99
1901	2000			100