All Robinson R44 Helicopters.
This Continuing Airworthiness Notice (CAN) is issued to draw operator’s and maintainers attention to the potential for contact between the fuel tank supporting structure and the braided hydraulic line.
This CAN is prompted by a recent incident where an R44 engineer found evidence of chaffing between the aircraft fuel tank support structure and the stainless-steel braiding of the hydraulic pump suction hose. Refer to Figure 1 in this CAN for bladder fuel tank chaffing damage.
It appears that the hydraulic pump fittings, to which the hydraulic hoses attach, were incorrectly orientated on installation. This resulted in insufficient clearance between the hydraulic suction hose and the fuel tank.
The chaffing could have resulted in rupture of the bladder fuel tank if the insufficient clearance between the hydraulic suction hose and the fuel tank had remained undetected.
Maintenance engineers are reminded of the following:
If any hydraulic hose and fuel tank chafing damage is found, complete a CA005 Defect Report form and submit the completed form to the CAA at CA005@caa.govt.nz or report findings via the online reporting system.(external link)
Please include all findings and any other relevant technical information. A CA005D Defect Report form can be obtained from https://www.aviation.govt.nz/about-us/forms/Filter/?SearchTerm=&Rule=8
Figure 1. Damaged fuel tank structure
Fig 2. Example of correct orientation of the fittings and hoses
Figure 3: R44 8-1A Hydraulic flight control system