SAO PAULO, Jan 29 (Reuters) - A U.S. bankruptcy judge on Monday allowed Brazilian airline Gol to borrow the first $350 million of its proposed bankruptcy financing, which a company attorney said was "desperately" needed to maintain normal operations.

U.S. Bankruptcy Judge Martin Glenn approved the initial funding at a court hearing in Manhattan, despite voicing some concerns about the high cost of the overall $950 million loan. Glenn will consider approving the rest of the loan at a future hearing, and said he needs more insight into the financing costs.

"I'm not writing a blank check," Glenn said.

The loan has an interest rate that currently exceeds 15%, over $235 million in additional fees, and additional attorneys' fees that could be added to that cost later, according to court documents.

Gol attorney Andrew Leblanc said the initial funding was "desperately needed" to maintain Gol's operations and preserve relationships with the lessors who own Gol's fleet of 141 Boeing aircraft, who could stop maintenance work or seek to reclaim airplanes if they are not paid.

In addition to the financing, Gol intends to use the legal protections of Chapter 11 bankruptcy to insulate its leases from outside interference, Leblanc said. A competitor airline has already reached out to Gol's lessors in an attempt to "poach" Gol's aircraft, according to Leblanc.

Gol filed for Chapter 11 bankruptcy protection on Thursday with about $8 billion in total balance sheet debt.

The company has $2.7 billion in liabilities coming due in the next 12 months, including $647 million for future air travel purchased by Gol's customers, $359 million owed to aircraft lessors, and $292 million owed to its lenders.

Gol is one of the world's largest low-cost airlines and a leading provider of domestic air travel in Brazil, serving 30 million passengers in 2023.

The company is the latest Latin American air carrier to file for bankruptcy in the United States, blaming the lingering fallout of the COVID-19 pandemic, and supply chain issues involving Boeing, including the 2019 grounding of its 737 MAX jet and delayed delivery of new aircraft that Gol intended to add to its fleet in 2023.

Gol has seen strong demand since the end of the pandemic, and its revenue grew by 16% to $4.66 billion in 2023, according to court filings.

Other airlines that have recently completed bankruptcy restructurings in the U.S. include LATAM Airlines, Grupo Aeromexico SAB, and Avianca Group International Limited.

Gol is 53% owned by Grupo Abra, which also owns Colombia-based Avianca. Gol's Sao Paulo-traded shares were down more than 19% on Monday afternoon at 4.76 reais each. (Reporting by Dietrich Knauth, Gabriel Araujo and Andre Romani; Editing by Steven Grattan, David Alire Garcia, Alexia Garamfalvi and Jonathan Oatis)