What happened
Following takeoff, the flight crew moved the landing gear handle to the raised position, which triggered the master caution light. This illumination indicated a loss of 'A' system hydraulics. In response to the mechanical failure, the captain declared an emergency and prepared for an arrival on runway 16L, which measured 12,004 feet in length and 150 feet in width.
The first officer performed the landing using 15 degrees of flaps at a speed of 140 knots. Upon deployment of the thrust reversers, the left unit malfunctioned, creating asymmetrical braking thrust during the rollout. Because the loss of the 'A' hydraulic system rendered nose wheel steering inoperable, directional control was required to be maintained through the use of rudder and differential braking.
During the landing roll, the captain took control of the aircraft from the first officer. Post-incident photographs of the scene showed that after 8,000 feet of runway usage, the tire skid marks became significantly darker, specifically noting that the two right-side skid marks were darker than the two left-side marks.
The investigation
The investigation noted a discrepancy between the actual landing speed and the speeds prescribed in the aircraft's operations manual. For an aircraft weight of 89,600 pounds experiencing a loss of 'A' hydraulic system functionality, the manual specified a required landing speed of 156 knots; however, the landing was performed at 140 knots.