Beleaguered Northwest Airlines has joined Delta on the verge of filing for bankruptcy protection.

No. 4 Northwest disclosed yesterday in a securities filing that it has missed $42 million in payments to creditors since Saturday, and that it won't make a $65 million payment into its employee pension plans due tomorrow.

Northwest's board will meet today to decide whether to seek protection from the carrier's creditors with a Chapter 11 bankruptcy filing, or to continue efforts to restructure outside of bankruptcy, said Will Holman, spokesman for Northwest's pilots union. The union has a seat on the board.

If the two large airlines file for protection this week, they'd join United, US Airways and discounter ATA in Chapter 11. Carriers representing more than half the USA's flying capacity would be operating under protection.

Northwest, faced with a strike and a massive increase in fuel costs since Hurricane Katrina, has warned for months of a Chapter 11 filing. Only the timing — a possible filing this week — came as a surprise yesterday.

Northwest share prices plummeted yesterday on a midafternoon report by The New York Times that, according to an unnamed source, a bankruptcy filing is imminent. Northwest shares closed at $1.57, down 53 percent.

Based on the later securities filing, analyst Philip Baggaley at Standard & Poor's said "it certainly seems evident" Northwest is heading to Chapter 11.

Northwest spokesman Kurt Ebenhoch said the airline "has made no decision regarding a Chapter 11 filing."

No. 3 Delta, meanwhile continued preparations yesterday for a Chapter 11 filing. The carrier has advised employees and retirees to expect major pay and benefits reductions.

Delta is asking for a second round of "comprehensive" pay and benefits cuts from its pilots union, according to the Air Line Pilots Association's Web site. Late last year, members of the union agreed to give back $1 billion in pay and benefits for five years to help the company stay out of bankruptcy court.

The union governing council will meet next week to decide whether to open negotiations with the airline, spokeswoman Kelly Collins said.

Cathy Cone, leader of an organization of Delta retirees, said Delta plans to reduce health insurance benefits for retirees, many of whom now receive free health insurance. Cone said Delta fears it won't qualify for crucial bankruptcy financing from General Electric and other lenders unless it makes cuts in retiree benefits.