Washington (CNN) -- The federal Transportation Security Administration failed to notify most airborne flight crews of the failed Christmas Day terrorist attack on a U.S.-bound plane, an airline pilots union said Wednesday.
The Allied Pilots Association (APA), which represents more than 11,000 American Airlines pilots, said the TSA sent security notices to U.S.-bound flights from Europe, instructing them to take certain precautions after the botched attempt on a Northwest Airlines flight from Amsterdam, Netherlands, to Detroit, Michigan.
However, no similar notice was sent to domestic flights or other international flights, the pilots group said.
"It was a confirmed attack. Everybody should have been notified," said Mike Karn, security chairman for the APA. "People were left in the dark."
Karn said the timely notification of airline crews is important because al Qaeda is known for launching simultaneous or nearly simultaneous attacks. Pilots can take precautionary measures if they learn of attacks elsewhere, Karn said.
On September 11, 2001, passengers of United Airlines Flight 93 thwarted hijackers' apparent attempt to strike a Washington target when they learned about plane attacks on the World Trade Center in New York. The plane crashed in a Pennsylvania field, killing all aboard.
Sterling Payne, a TSA spokeswoman, said the decision on notifying pilots was based on the perceived risk at the time.
"When the incident occurred, TSA immediately stood up a conference call with partner agencies including FAA and others," Payne said Wednesday. "Based on intelligence information at that time, a strategic, risk-based decision was made to notify all 128 flights inbound from Europe."
In interviews Sunday and Monday, Homeland Security Secretary Janet Napolitano said 128 flights in the air were notified to take "special measures" due to the attempted bombing of the Northwest flight. Initially, Napolitano referred to "all 128 flights in the air," but on Monday she specified to Fox News that the 128 flights were from Europe.
In a letter to its members, the Allied Pilots Association said the TSA should have ordered that information about the incident "be passed on to all airborne flights."
"Clearly, we have seen a large-scale communications breakdown concerning this terrorist event," the APA said in the letter. It said the group was recommending that the TSA mandate that all airborne flights be notified of serious security events in the future.
"It is essential in times like these that we act swiftly to ensure our crews are prepared to thwart any terrorist attack," the letter said.