Boeing (BA.US) is reportedly planning to sell its navigation division, Jeppesen, in an effort to alleviate its $58 billion debt burden.

Under pressure to improve its performance, Boeing (BA.US) is considering selling its highly regarded navigation unit, Jeppesen, which is valued at over $6 billion, according to sources familiar with the matter.

Raytheon and Honeywell International are among the companies currently evaluating the potential sale, the sources said. Buyout firms Advent, Blackstone Group, Carlyle Group, Thoma Bravo, Veritas Capital, and Warbug Pincus also expressed interest in Jeppesen by Jan. 29.

Other potential bidders include General Electric's (GE.US) aerospace unit and TransDigm Group (TDG.US).

Jeppesen's first-round bids are due next week. The profitable business, which provides interactive flight planning, has a wide customer base ranging from airlines to amateur pilots. Boeing bought Jeppesen for $1.5 billion in cash in 2000, and it is one of the assets the aircraft maker is considering spinning off as it seeks to reduce its $58 billion debt load.

Boeing faced its largest strike ever in the second half of last year, with its commercial aircraft factories in the West Coast idled for much of the quarter as 33,000 hourly workers walked off the job to demand higher pay and better benefits. The strike lasted seven weeks before Boeing reached a new contract with its largest union that will give workers a 38% pay raise over the next four years, ending the strike and restarting production.

Boeing's fourth-quarter loss per share was $5.46, far more than the $1.57 loss that analysts had expected.