When you look in between the fanblades, through the first stage booster vanes of the LPC, you can see the outer shroud abradable coating. Especially at the 6 o’clock position you will certainly find damage to this coating. This damage looks like corroded aluminum, but it is a composite coating which is peeled and cracked, and may be missing untill certain limits. The damage starts at the 6 o’clock position and continues to the left and right side. The cause of this damage is not exactly known, but probably the damage starts when moisture accumulates at the lowest point, and when it freezes it will expand and therefore damage the coating. (If anyone has more info please let it know!) Many parts and chuncks are coming off. The inspection is stated in AMM 72-21-03 page 601 ff. There are the damage-limits of this outer shroud abradable coating. You can replace this splitter fairing on-wing iaw the same AMM chapter page 401 ff. See the pictures taken from such an assy, where the damage was present from the 3 o’clock till the 9 o’clock position. Note the many parts missing and the chunck of coating on the last picture.
