Transport Canada issued an emergency airworthiness directive (AD) on Friday limiting the Airbus A220, formerly the Bombardier C Series, to a maximum setting of 94 percent N1 above 29,000 feet. According to Transport Canada, the directive is due to several occurrences of inflight engine shutdowns on Pratt & Whitney-powered A220s. The AD (PDF) covers A220s with Pratt & Whitney PW1521G-3, PW1524G and PW1524G-3 engines. Switzerland’s Federal Office for Civil Aviation (FOCA) issued a similar directive on Monday.
“Preliminary investigation results indicate high altitude climbs at higher thrust settings for engines with certain thrust ratings may be a contributor,” Transport Canada said in the AD. “This condition, if not corrected, could lead to an uncontained failure of the engine and damage to the aeroplane.” The department says its investigation is ongoing and Friday’s AD is considered an interim action.
As previously reported by AVweb, Swiss International Airlines grounded its A220s earlier this month following a third engine failure in its fleet. It began returning its aircraft to service the next day following engine inspections. An FAA AD (PDF) requiring “initial and repetitive inspections of the low-pressure compressor (LPC) inlet guide vane (IGV) and the LPC rotor 1” on a number of Pratt & Whitney turbofan models including the PW1521G-3, PW1524G and PW1524G-3 was issued following Swiss Airlines’ second in-flight engine shutdown in September.