Nok Air (DD, Bangkok Don Mueang) has been obliged by the Civil Aviation Authority of Thailand (CAAT) to revise its Summer 2018 schedule taking into account the actual availability of aircraft in order to avoid repeat delays, for which the Thai low-cost carrier has recently been criticised, Thai PBS has reported.

The carrier has run into operational problems recently as some of its aircraft have been grounded for maintenance. This has led to numerous delays and prompted the CAAT to ask for a new business plan which would take its fleet limitations into account better. Nok Air has also been obliged to present its plan to continue operating some of the loss-making sectors and its strategy for crew management.

The CAAT will also perform an audit of the carrier's maintenance standards and pilot qualifications.

Out of the carrier's active fleet of nineteen B737-800s, HS-DBT (msn 61293) has been grounded since March 9 due to engine maintenance requirement based on routine inspection. The aircraft is expected to return back into service mid-April 2018. Another unit of the type, HS-DBJ (msn 32616) has been grounded since mid-December 2017 as it undergoes a redelivery C-Check prior to the return to the lessor.

One of the airline's eight Dash 8-400s, HS-DQD (msn 4480) has also been grounded for maintenance since February 20, Flightradar24 ADS-B data shows, and is tentatively scheduled to return to service in by the end of March. The carrier also operates two ATR72-500s.

The Thai LCC is 21.6%-owned by Thai Airways International. Last year, Nok Air raised nearly THB3 billion baht (USD96.1 million) from existing shareholders to partially cover for some THB5 billion baht in losses incurred from 2014 to mid-2017. The carrier has recently been revamping its business strategy in order to better align with Thai Airways and Thai Smile, but has been struggling to find a market position amid woes of overcapacity and a price war in Thailand caused by the expansion of Thai AirAsia, Thai Lion Air, and Thai VietJetAir.