PHILIPPINE Airlines yesterday allayed fears of an impending strike by its ground staff in Manila, saying both management and the employees are careful not to allow their dispute to affect service to the passengers. ''We are at the peak of the collective bargaining cycle,'' said Mr Roberto Diaz de Rivera, PAL's Hongkong sales manager. He said labour-management relations continued to be harmonious, and talks were continuing under the auspices of the National Conciliation and Mediation Board (NCMB). Mr de Rivera said even if ground staff supported the strike in a vote on June 3, the government was likely to step in because PAL belongs to an industry identified by existing laws as be indispensable to the national interest. ''Under the law, the government is required to avert strikes in vital industries such as air transportation, and to conduct mediation proceedings between the management and the labour union until their differences are resolved,'' Mr de Rivera said. Previous disputes had been resolved by the NCMB. ''The NCMB is already involved in the present negotiations,'' Mr de Rivera added. ''We expect PALEA's leaders to continue to exercise responsible leadership.'' He added that PAL could engage contractors to handle the check-in counters, and travel agents to handle the ticketing. The Philippine Airlines Employees Association, he added, represented only the ground staff. Pilots and the flight attendants had their own unions, which were not party to the current dispute.