Resumption of ATR aircraft operations hinges on clearance

Pakistan Civil Aviation Authority (PCAA) - despite carrying out a shakedown test of ATR aircraft - appears reluctant to resume its operations without getting clearance from Pratt & Whitney (P&W), an ATR aircraft manufacturer; it was learnt here.
The PCAA in a letter sent to COO Pakistan International Airlines (PIA) and secretary aviation has shown its inability to inspect internal conditions of ATR engines and directed the airline to approach OEM for the said purpose as the clearance of engine for operation resumption of ATR should be sought through any technical expert from P&W.
The letter said that PCAA was doing its best to assist PIA in evaluation of the current status of ATR aircraft fleet by performing the Shakedown Inspections and directed the airline to inspect internal conditions of ATR engines either from PIA engine specialist staff or the representatives of OEM, who could provide the true picture of internal conditions of all the installed engines.
The PCAA in its letter said that they had reviewed the complete system for maintenance of ATR in PIA and after the review of technical records of all aircraft, some significant observations had been noticed and the airworthiness field offices were indicating shortcomings in maintenance, quality assurance and airworthiness management system of PIA. The safe operation of ATR aircraft requires not only compliance with regulatory requirements but also with recommendations of OEM of aircraft and its engines. The engine trend analysis and the health monitoring of engines is the prime responsibility of PIA.
It said that PCAA collected the statistical data of total engines failed since the induction of ATR aircraft, adding that the analysis of data was reflecting an alarming trend of engine failures due to HPT blades, main bearings, surging and oil system issues.
Moreover, the letter said that in 2007, at the time of induction of ATR aircraft, the HPT blades hard time life given by OEM P&W was 15000 cycles. The total life of HPT blades should have been 15000FHrs but within a span of (04) four years, PIA had (06) six in-flight shutdowns, due to which, on the recommendations of OEM, PIA had agreed to reduce the life of Hot Section components to 5000FHrs.
Even with adoption of program for replacement of HPT blades at 5000FHrs, the critical issue of In-flight shutdown could not be controlled. As per data for premature failure of PW 127 engines, PIA had 20 incidents of In-flight shutdowns due to HPT blades failures. It is evident from the records that beside turbine blades numbers of engines failed due to bearings failure, High EGT, Surging of compressors, seizure of impellers, breaking of Spline Shaft of accessory gear box, etc. Total cases of schedule/un-schedule engine removals were 90 and out of these, most of the cases are attributed to core engine component failures.
The PCAA in a letter also stressed the need for addressing all the observations made during Shakedown inspections on priority for early restoration of ATR fleet operation. Meanwhile, PIA spokesman said that on the direction of PCAA it has contacted P&W for the inspection of internal conditions of ATR engines. He claimed that the letter had been written after the December 7 crash but the airline had been doing inspection and maintenance of its aircraft as per manuals at proper times in accordance with international standards.