what does write-off mean in this question ? it is unavoidable so it is not relevant ,but I cannot understand why it is write off

Relevant Costs Worldwide Airways is thinking about replacing a three year old loader with a new , more efficient loader . New loader List price 15 , 000 Annual operating expenses 45, 000 Expected life in years Old loader Original cost $ 100, 000 Remaining book value 25, 000 Disposal value now 5, 000 Annual variable expenses 80, 000 Remaining life in years 14- 11If we keep the old loader , we will have depreciation costs of $25, 000 . If we replace the old loader, we will write - off the $25, 000 when sold . There is no difference in the cost , so it is Not relevant. We will only have depreciation on the new loader if we replace the old loader . This cost is relevant. THE ${ ``` proceeds will only WE TEEl`` If WE `ENGAGE THE `| loved`` THE Elmont 's TE| EVEIN`