It’s been one week since American Eagle Flight 5342 crashed into the Potomac River, and the work has only begun to recover from the deadliest U.S.

But the day after American Airlines Flight 5342 collided with a U.S. Army helicopter in Washington, D.C., killing all 67 people onboard, shares of the company were trading just 2.5% lower. The decline grew four days later, with shares trading 4.5% lower than the day before the crash.

With no survivors expected, the Jan. 29 midair collision between an American Airlines plane and a U.S. Army Black Hawk helicopter would make it the third deadliest commercial aviation disaster in the U.

Pilots and flight attendants are aware of risks, but commercial aviation tragedies have been infrequent in the U.S. for years.

The communication team at American Airlines had to activate a crisis plan it hoped it would never have to use after last week's midair collision of a passenger jet and Army helicopter that claimed 67 lives.