NEW YORK (CNNMoney) -- American Airlines and its pilots union blamed each other Monday for a surge in flight cancelations and delays tied to contract issues at the bankrupt carrier.
Flight tracking service FlightStats.com says 103 flights were canceled as of midday, the second highest one-day number of cancelations since problems at the airline began on Sept. 16. That brought the total number of flights canceled to 570, or about 3.5% of its total schedule.
Less than half of American's flights have been on time in the past eight days, according to FlightStats.
American, which said last week it would reduce its flights by 1-2% to deal with service problem, took issue with the cancelation number. Spokesman Bruce Hicks said many of Monday's grounded flights were scrubbed in advance.
Hicks said the performance problems are due to what he calls questionable complaints about aircraft maintenance, and an increase in pilots calling in sick.
Long-simmering battles between the Allied Pilots Association, the union representing about 8,000 active pilots at the airline, and American management, got worse when the bankrupt airline won the right in bankruptcy court to throw out the existing pilots contract. The terms of employment under which the pilots now work under require them to fly more hours and allow the airline to use other carriers to fly more of its flights.
Management has also stopped funding the pilots' pension fund and has proposed to either freeze or terminate their retirement plan. Pilots voted overwhelmingly against a tentative agreement last month that was better than the terms that were recently imposed upon them.
The union says there is no organized campaign by pilots to call in sick or file trivial maintenance reports. It said problems being written up are serious ones that have the potential to turn into safety issues if not addressed.
"Our pilots will not compromise safety, ever," said APA President Keith Wilson. But he conceded the contract status is at least a factor in the increase number of complaints.
"Understandably, our pilots are taking a prudent and cautious approach in their operational decision-making process," Wilson said.
Hicks said it is too soon to say if American is losing passengers and revenue because of the ongoing service problems. He admitted that the on-time performance has deteriorated significantly this month, to about 53% from better than 80% a year ago.