Highly trained employees, including pilots, air traffic controllers and aircraft maintenance workers have filed requests to resign.

The turnover threatens to destabilize Vietnam Airlines's ongoing operations, according to Transportation Minister Dinh La Thang.

The national carrier was ordered to increase salaries and allowances for these workers in the first quarter of the year.

Lai Xuan Thanh, director of the Civil Aviation Authority of Vietnam (CAAV) said he has declined to accept resignations from many Vietnam Airlines employees prior to implementing the ministry’s directive.

However, he did not confirm the reason for the attempted mass exodus from Vietnam Airlines.

Meanwhile, local media has blamed the salary gap between Vietnam Airlines and its competitors (and foreign and local pilots) as the underlying reason. Last October, more than ten pilots in the 919 Flight Crew Division attempted to resign, Dan Tri newspaper reported.

So far, none have been allowed to leave

Each Vietnamese pilot at Vietnam Airlines earns around VND80 million (US$3,742) a month, depending on his or her position and aircraft, while a foreign pilots gets $8,000-13,000 a month.

The difference was questioned several years ago and Vietnam Airlines explained that it did not have to pay to train foreign pilots, at a cost of around VND2.5 billion ($117,000).

Vietnam Airlines requires each of its pilots to commit to working for the company for at least 15 years if it covers the cost of their training.

The company has about 600 local pilots, who represent roughly 70 percent of the firm's fleet.

In November 2013, many engineers at the Vietnam Airlines Engineering Company complained that they had been forced to sign 20-year contracts with Vietnam Airlines, after the private budget carrier VietJetAir announced plans to recruit aviation engineers for salaries that were up to three times higher.

By Thai Son - Thanh Nien News - January 12, 2015