Hi again every one.
I gave the following questions and ideas that every one put forward through to the engineers on Monday. Unfortunately the machine is not ready for test flights yet, for some other reason, so I hven't been around to the airport for the checks in person.
Here are all your questions and answers in red from them.
- What are the bearings at the other end of the PCL's like? Serviceable with no significant wear
- What is the condition of the bearing in the Pitch Change spider? Serviceable with no significant wear
- If the inner bearings (rubber) are U/S it may allow the spider to get out of whack with the blades.Not worn at all
- Inter-granular corrosion on the pitch horn visible? Tell us what the PCL bearings are like on the Spider end. No corrosion
- When was the last T/R rigging check done and by whom? 550hrs ago at major inspection
- What other repair, overhaul, component replacement take place since that time. None
- Can pedal travel cause this problem if the aircraft is correctly rigged? No
- Was the tail rotor installed properly....and alignment checked?
Rigging seems to be the problem, so there is need to get those doing the rigging sorted. I have flown on the Safari Rally which requires full pedal to be used for 60-70% of the time and have never had the problems that your photos show.
Tail rotor was installed correctly with the problem only showing up during the last service interval
- The PCL end sure looks like FOD to me or damage done during the last time it was off during maintenance Not correct - worn from above snag
- If there is play in the spider or PCL's that would have been picked up No excessive play. Well within limits
- I would have a guess that the other damage could be due to someone inexperienced changing the spherical bearings Not correct
- The scores on the pitch horns and pc link are most likely from the T/R control being slightly out of rig, allowing excess right pedal input so they contact the T/R hub See 8 above
- The impact marks on the half shell lam's are most likely caused by the T/R hub spherical laminates being sheared, allowing excess blade flap under high loads w/ right pedal input. Bearing still serviceable, no wear marks
- Unfortunately have seen both problems in the past. Good thing they were caught sooner than later. As far as serviceability, the MM says impact marks lass than 5mm can be filed out, more than 5mm requires replacement. Below 5mm
- Get your engineers to refit the tail rotor assy and the old pitch change links. Fit Hydraulic rig and check that the tail rotor stops under the cabin floor are contacted at full left/right pedal. Then check the dimensions for the pitch change spider/tail rotor shaft dimensions at full left/right pedal as per maintenance manual. This will prove if there is a rigging fault. A very easy check to carry out with a rigging kit and hydraulic rig.
Do a wear check on the pitch change bearings to check within serviceable limits eliminates another possibility and change the pitch change links for new ones the damage is nasty! Do a spider bearing wear check to ascertain serviceable.
Done, carried out
Still the mystery carries on... I'll keep everyone updated on any new developments "if we find any"...
Thanks again for the help