An aircraft from Air Incheon makes a landing at Incheon International Airport in this undated file photo. Courtesy of Air Incheon

Korean Air has selected Air Incheon as the preferred bidder for the sale of Asiana Airlines' cargo freighter business, overcoming a major hurdle in the long-delayed acquisition of Asiana, the company said Monday.

In a regulatory filing, the nation's flag carrier tapped Air Incheon — the nation's sole all-cargo airline — as the preferred bidder for the deal. The sale of cash-strapped Asiana Airlines' cargo unit was part of a precondition before the European Union (EU) granted conditional approval for the operational merger of the two airlines.

Korean Air took into consideration several key criteria before selecting Air Incheon. This included the certainty of completing the transaction, the ability to maintain and enhance the long-term competitiveness of the air cargo business and the capability to mobilize funds through a competent consortium, according to a statement from the Korean Air. The decision was made during the Korean Air's board meeting on Monday morning.

The specific bidding price remains unknown, but the industry estimates it was worth around 500 billion won ($362 million).

Air Incheon was founded in 2012 as the only cargo-focused airline here. The airline focuses on Asia, but will be able to strengthen its competitiveness in long-haul routes by utilizing Asiana's network expertise in America and Europe, according to Korean Air.

Korean Air plans to sign a framework agreement with Air Incheon in July after reaching specific terms of conditions. The agreement is also subject to review by the European Commission.

"The preferred bidder was selected through a comprehensive evaluation of all factors crucial to the growth of the air cargo industry, a key national industry, while maintaining the existing competitive environment," a spokesperson at Korean Air said. "We are committed to quickly finalizing the sales process through flexible negotiations, and completing the acquisition of Asiana Airlines."

Air Incheon's acquisition of Asiana's cargo unit will help the former rise to the nation's second-largest cargo business operator after Korean Air. Asiana's cargo business accounted for 19.4 percent of its market share during the first quarter by chalking up sales of 353 billion won during the period.

The latest announcement is also expected to speed up Korean Air's acquisition of Asiana Airlines. A group of 13 out of 14 global authorities approved of the takeover, and the U.S. Department of Justice is reviewing the case. Korean Air expects the U.S. authority to grant approval before the end of October. The airline hopes to finalize the remaining legal procedures by the end of this year.

However, it will take a couple of years for Korean Air to launch a new combined entity. Korean Air also plans to combine three low-cost carriers — Jin Air, Air Busan and Air Seoul — affiliated with Korean Air and Asiana Airlines.