Date: 201209
Local time of day: 0001-0600
Location: ZZZ.Airport, US
Light: Dusk
Aircraft: B737-800
Operator: Air Carrier
Operating under: Part 121
Flight plan: IFR
Mission: Passenger
Flight phase: Final Approach
Airspace: Class B ZZZ
ATC / advisory: Tower ZZZ
Aircraft component: Aileron
Component problem: Malfunctioning
Reporter organization: Air Carrier
Reporter function: Captain; Pilot Not Flying
Reporter qualification: Flight Crew Air Transport Pilot (ATP)
Human factors: Workload; Training / Qualification; Time Pressure; Situational Awareness
Second reporter function: Pilot Flying; First Officer
Anomaly: Aircraft Equipment Problem Critical
Detector: Automation Aircraft Other Automation; Person Flight Crew
When detected: In-flight
Result: Flight Crew FLC complied w / Automation / Advisory; Flight Crew Landed in Emergency Condition; General Declared Emergency; General Maintenance Action
Contributing factors: Aircraft
Primary problem: Aircraft

Narrative: Cleared for a 12 mile visual approach backed up with the ILS. Localizer and G/S captured and missed approach altitude set. [We] started to configure the aircraft. Airspeed was approximately 205 KTS. First Officer called for flaps 1; then flaps 5; gear down. After I positioned the gear handle down I looked at the flap indicator to confirm degrees of flaps and noticed that the flaps had not advanced beyond 1/2 to 1 degree. I started to say something was wrong with the flaps when we got a Master Caution Light and we then determined that we had indeed lost the B System hydraulics. There was no oil in the B System. B LOW PRESSURE lights on and yaw damper had kicked off. 6 miles out and runway insight; gear down and on speed and on slope for the no flap configuration. Declared an emergency; requested Crash and Fire and was cleared to land. We got the QRH out and started to run very long System B fail checklist and then discussed landing on this runway with no trailing flaps as opposed to taking this aircraft up again with approximately 6;000 LBS of fuel and maybe even developing more problems than we had. Very quickly we then discussed the systems that had failed such as normal brakes and auto brakes; spoilers and that we still had alternate brakes and the left thrust reverser. We then discussed the fact that we have been trained for no flap maneuver and we knew what to expect as far as the aircraft pitch attitude and to control the rate of decent prior to touchdown. We decided that we wanted to take advantage of this 12;000 FT dry; grooved runway with Crash and Fire available and that was now about 4 miles in front of us and decided to land with flaps in the up position. Stopped the B FAIL checklist and ran the normal landing checklist and the gear was down and locked. [We] maintained a speed of ref 40+40 until touchdown. [We] landed inside the touchdown zone at about 1;000 FT; speedbrakes out and the 1 thrust reverser in operation. Applied manual brakes with constant pressure and the aircraft decelerated at a very comfortable and consistent rate. Alternate brakes worked as advertised. We could have made Intersection N with the braking performance that the alternate braking system provided us but [we] let the aircraft roll out to Intersection P at a very nice rate with minimum braking pressure required. Cleared at P and did the after landing check told Ground that we need to pull off to the side and stop the aircraft because our ability to stop and steer the aircraft in close quarters was in doubt. Ground told us to taxi onto the W line and switch to Ramp frequency. We then asked Ramp to have Crash and Fire drive around the aircraft and assess any damages that they spotted and pass that along to us as that would help us make more sound decisions about taking care of our crew and passengers and aircraft. Crash and Fire reported no fire or smoke and could not see any visible damage to the aircraft. Contacted the cabin crew and briefed them on our situation and they reported that they and our passengers were fine. Contacted Maintenance and Operations and briefed them about the loss of the B System and requested a tow to gate. Made a PA explaining our situation to the passengers and ask for their cooperation in this matter. Started the APU and shut down both engines and was then towed to the gate. All of our passengers deplaned the aircraft saying thanks you and good job as we said good bye to them. We then had a debrief with our cabin crew and they said that they didn't feel anything out of the ordinary on landing. They then went on to work another segment. Put the write up in the book. Maintenance came up to the aircraft and told me that the B System autopilot aileron actuator had failed and that the wheel well was covered with oil. Maintenance took control of aircraft.


Second narrative: [Narrative 2 contained no additional information.]


Synopsis: A B737-800 Aileron Autopilot Actuator failed on final approach at flaps 1 causing the loss of System B Hydraulic Fluid so an emergency was declared; the airspeed adjusted and the flight continued to a normal no flap landing.