Island Air’s aircraft lessor has filed a much-anticipated lawsuit in federal Bankruptcy Court that eventually could result in the shutdown of the state’s second-largest carrier.

Wells Fargo Bank Northwest, National Association, the aircraft trustee for Ireland-based lessor Elix Assets 8 Ltd., requested in a 565-page complaint filed Tuesday that the court rule that leases for the three Q400 aircraft still being used by Island Air were terminated prior to the airline’s Oct. 16 bankruptcy filing. The complaint requests Island Air be prohibited from using those three aircraft because it has no right to their continued possession, and that the airline pay the lessor $4.58 million owed as of the bankruptcy filing under the lease agreements.

Elix said Island Air’s continued use of the aircraft, which are worth about $75 million, is causing daily depreciation and that Elix is negotiating with a new potential lessee for the lease of each aircraft to mitigate the lost rental and maintenance reserve income from Island Air’s default.

The lessor said Island Air, which has not made any payments since June 30, would over the coming months continue to owe it $204,000 per month in rent and about $140,000 monthly in maintenance reserve obligations. In the meantime, Elix said, it is obligated to pay principal and interest to its own lenders in excess of $725,000 a month.

Island Air attorney Ted Pettit, Island Air CEO David Uchiyama and Jeffrey Au, manager of the two investment groups that own two-thirds of the airline, did not respond to emailed requests for comment.

In one of several motions filed separately Tuesday, the lessor requested the bankruptcy stay be lifted to clear the way for Elix to repossess the aircraft. A hearing is scheduled for 9:30 a.m. Nov. 15.

The airline, which previously had five Q400s in its fleet, lost the use of two of them last month when they were taken back by Nordic Aviation Capital over a similar lease dispute.

With just three planes now remaining in its fleet, a ruling in favor of the lessor likely would force Island Air, which has more than 400 employees, to convert its reorganization case to a liquidation. That path would be similar to the one taken by Aloha Airlines, previously the state’s second-largest airline, when it filed for Chapter 11 reorganization on March 20, 2008, and then ceased operations 11 days later.

Hawaiian Airlines, which was prepared to step in when Aloha Airlines and then, later, go! ceased operations in Hawaii, has hired local counsel to monitor the proceedings.

“Having been through Chapter 11 before, we know that successful reorganization is possible under this section of the Bankruptcy Code and we hope for the best outcome for Island Air and all of its customers,” Hawaiian Airlines spokeswoman Ann Botticelli said in an email.