Cause of deadly airline-helicopter crash remains unclear amid conflicting flight altitude data

The cause of deadly airline-helicopter crash last week outside of Washington, D.C., remains unclear amid conflicting flight-altitude data. 

Data from the flight recorder for the commercial American Airlines jet shows the craft's altitude was at 325 feet, plus or minus 25 feet, when the crash took place, according the to National Transportation Safety Board. 

However, control tower data showed the Black Hawk helicopter at 200 feet at the time of the crash, according to the Associated Press.

The collision between the jet, as it was landing at Reagan National Airport, and an Army Blackhawk helicopter that was on a training mission and supposed to be maintaining a maximum altitude of 200 feet, occurred Wednesday night. 

The aircraft plummeted into the Potomac River. All 64 plane passenger and the three people on the helicopter were killed.