12-13-79-610-011-A - Check Oil Level and Replenish.

Reason for the Job:
This task gives the instructions necessary to fill the engine oil tank if the oil level has decreased during normal engine operation. [...]
(A). Check the engine oil level.
(4) Servicing is not required prior to departure if the engine was serviced on arrival or the oil tank sight glass shows a minimum of 23 quarts or the cockpit indication shows a minimum of 19 quarts and predeparture walkaround checks confirm no oil pools/drips from drain mast. [...]
(B). Fill the engine oil tank - Gravity Filling:
(2) Make sure that the oil level sight glass shows FULL.
NOTE: Do not fill the oil tank past the sight glass FULL level. Filling to tank overfill will result in excess oil, leading to amber cross indication warnings and service disruption.

Question: Why is there a difference in requirements in paragraph (A-4) and (B-2)? Whichever is correct?


2 Answers 2


When you check the oil on your car:

  • If the oil is above "ADD" line, you don't have to add oil for your next trip as long as the engine isn't obviously leaking. There's enough to get you to the next opportunity to check it, based on normal allowable consumption rates.
  • If the oil is below the "ADD" line, don't just add enough to get it above the ADD line, fill it all the way, being careful not to overfill.

The AMM task is a fancy version of that.

  • $\begingroup$ Sorry, this AMM reference For Aircraft.. $\endgroup$ Commented Aug 7, 2022 at 14:34
  • $\begingroup$ Yes I know. I was explaining the logic of the maintenance Task. When replenishing, the airline's procedure is fill it all the way because partial fills will just cause more unnecessary servicing maintenance later. Part A is based on the allowable minimum to get you to the next check interval. $\endgroup$
    – John K
    Commented Aug 7, 2022 at 15:06

I don't see a difference.

(A) prescribes the check conditions that determine whether (B) has to be done.


  • (
    • the engine has been serviced on arrival, OR
    • the oil sight glass shows at least 23 quarts, OR
    • the cockpit indicates at least 19 quarts
  • )
  • AND the engine is not leaking oil from the drain mast

THEN no service is required.

ELSE perfom actions under B

  • 1
    $\begingroup$ Thinks, this good Answer. $\endgroup$ Commented Aug 7, 2022 at 14:32
  • $\begingroup$ Hello Marwan, welcome to aviation.stackexchange. If the answer solved your problem, you can accept it by clicking the tick mark below it. $\endgroup$
    – DeltaLima
    Commented Aug 10, 2022 at 11:16

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