Xiaojun Xu

Dear Sir: We CKK (China Cargo Airlines) have 18 PW4460(-3) on-wing engines with 4 spare engines and another 4 spare EECs in the stock.Totally,26 EECs were affected by the propsed AD. Most of EECs fall into Group 2(Pls find the attached Excel file for the details) ,and our engines and EECs has been used over 15 years ,namely over 10000 cycles since new.So we should replace most EECs of the on-wing engine per your proposed AD in about 3 months,we connected Hamilton Sundstrand and they informed us that it should take about 3 to 6 months include the transportation to comply the inspection of the suspect PWM for one EEC.Then,it will definitely cause AOG for our company . So,we suggest that FAA can issue the AD refer the P&W SB PW4ENG 73-215,73- 216 to arrange the EEC fleet management ,besides,you can find in the SB that ” Group 2”— EECs that have a LOW probability of containing faulty Pulse Width Modulator (PWM) microcircuits,so we suggest FAA can deeply re-consider the requirements and comply deadline . Best Regards. Xu Xiaojun Engine Control Center. Maintenance&Engineering Division,China Cargo Airlines Ltd. Tel: 86-21-62683545 Fax: 86-21-62682643