Although F-28s are known for recurring technical flaws, Biman authorities seem to have a liking for them, aviation sources pointed out.

Despite the technical troubles its previous F-28 fleet of three aircraft faced and opposition from pilots, Biman Bangladesh Airlines bought two 28-year-old F-28s in May this year raising the fleet strength to five.

On its maiden flight on June 6, one of the two newly bought F-28 aircraft could not take off from Zia International Airport (ZIA) on a flight to Jessore due to engine trouble, reminding Biman authorities of its track record. The two aircraft bought from Hiebert Group Ltd. of Indonesia cost $2.91 million.

Biman authorities however claimed F-28 planes are most suitable for short routes and its prices are also within the financial capability of the national flag carrier. But flight records of the two latest procured F-28s since their purchase showed the 1977-model aircraft developed the highest number of technical faults among the 15-aircraft Biman fleet.

Three faults in 10 flights of a plane are acceptable in aviation engineering, but F-28s' technical flaws number more than six in 10 flights. Manufacturer of F-28 series Fokker Aviation Ltd. of the Netherlands closed its aircraft-manufacture and also maintenance service in 1987, sources mentioned.

So, Biman has to maintain a large team of engineers for the maintenance F-28s. Their spare parts are also not easily available and are very expensive, resulting in a huge maintenance expenditure.

One of the two newly procured planes (Caab Reg-ADY) remains grounded at ZIA since July 6 when it developed a major technical flaw minutes before take-off from Chittagong airport.

An F-28 plane faced a major accident at Sylhet airport on October 8 as it skidded off 150 metres from the runway and fell into a canal injuring 30 of the 83 people on board. The crew were stranded in the cockpit and rescued after three hours of the accident.

The insurance company concerned declared the plane abandoned. After settlement with the insurer, Biman has retained the plane to use its engines and spare parts.

Biman is now left with three F-28s for its domestic and regional flights and is finding it difficult to maintain flight schedule as these aircraft are also facing frequent technical troubles.

On October 11, a scheduled flight from Kolkata to Dhaka was delayed by 13 hours as Biman could not manage a plane.

On Thursday at 9:15am, a flight from Sylhet to Dhaka was cancelled as pilots detected breakdowns in one of the two engines in the F-28 plane. Engineers from Dhaka flew to Sylhet and they repaired the engine at 6:15pm.

One source seeking anonymity said Biman's F-28s develop trouble at least once a day.

But Biman Managing Director M Mahmoodur Rahman argued that technical faults in F-28s are nothing unusual and are within acceptable limit. "Most of the technical faults of F-28s are minor, easily repairable and the cost is not so high. Similar faults also occur in DC and Airbus planes but the issue of F-28s always comes into focus," he told The Daily Star yesterday.

Captain SM Nasimul Haque, president of Bangladesh Airline Pilots Association, blamed old age of F-28s for their frequent faults. "All the F-28s are over 20-year-old and their maintenance standard is not up to the mark. Spare parts are also rare. So, if one is grounded due to faults, it is hard to bring it back to smooth operation," he said.

Biman should stop procuring old planes to minimise maintenance cost and avoid flight disruptions, he thought.