Narrative:

Working with aircraft maintenance technician (amt) 'Y' in ZZZ. This was a repeat write-up; three or four times. Amt Z and I had worked [same aircraft] two weeks prior. We found the right wing anti-ice control valve leaking at [forward] clamp. Crew reported a whirling sound coming from the right side leading edge wing root area during flight. The sound started a couple of minutes after selecting right wing anti-ice 'on'. The sound went away as soon as the right wing anti-ice was selected 'off'. We gained access to the right wing anti-ice plumbing and performed leak checks. First problem: noted bleed air leaking at the tee fitting where it connects to the inboard leading edge. Upon disassembly it was noted that the o-ring in the leaking connection were of a different size than the ones in the non-leaking connection. The illustrated parts catalog (ipc) shows the same part number seal in all three connections.second problem: looking thru the access panel in the inboard leading edge towards the wing tip I could see there was damage to the heat blanket at the connector where the inboard and outboard come together. We removed the inboard leading edge for a closer examination. We found more heat blanket damage and found the o-ring for the outboard leading edge was missing; causing metal to metal contact. This metal to metal contact damaged the bell connection to the outboard leading edge. The other o-ring was compromised and its bell connection was damaged as well. [Recommend] technicians need to pay closer attention to the ipc and ensure the o-ring they are installing belongs in that position. Double check to ensure there is a seal in the component before installation especially if it cannot be leak checked after installation.

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Original NASA ASRS Text

Title: An Aircraft Maintenance Technician (AMT) describes the progressive troubleshooting that he and another Technician applied to locate the cause of a whirling sound coming from the Right-Hand (R/H) Leading Edge Anti-Ice ducts on a Cessna CE-560XLS aircraft. Damage also found to Heat Blankets used to protect the fuel tanks from excessive duct heat was caused by missing; undersized and deteriorated orange colored O-Rings at pneumatic duct connections.

Narrative: Working with Aircraft Maintenance Technician (AMT) 'Y' in ZZZ. This was a repeat write-up; three or four times. AMT Z and I had worked [same aircraft] two weeks prior. We found the right wing anti-ice control valve leaking at [forward] clamp. Crew reported a whirling sound coming from the right side leading edge wing root area during flight. The sound started a couple of minutes after selecting right wing anti-ice 'on'. The sound went away as soon as the right wing anti-ice was selected 'off'. We gained access to the right wing anti-ice plumbing and performed leak checks. First problem: Noted bleed air leaking at the tee fitting where it connects to the inboard leading edge. Upon disassembly it was noted that the O-ring in the leaking connection were of a different size than the ones in the non-leaking connection. The Illustrated Parts Catalog (IPC) shows the same part number seal in all three connections.Second problem: Looking thru the access panel in the inboard leading edge towards the wing tip I could see there was damage to the heat blanket at the connector where the inboard and outboard come together. We removed the inboard leading edge for a closer examination. We found more heat blanket damage and found the O-ring for the outboard leading edge was missing; causing metal to metal contact. This metal to metal contact damaged the bell connection to the outboard leading edge. The other O-ring was compromised and its bell connection was damaged as well. [Recommend] technicians need to pay closer attention to the IPC and ensure the O-ring they are installing belongs in that position. Double check to ensure there is a seal in the component before installation especially if it cannot be leak checked after installation.

Data retrieved from NASA's ASRS site and automatically converted to unabbreviated mixed upper/lowercase text. This report is for informational purposes with no guarantee of accuracy. See NASA's ASRS site for official report.