MD-11
Flight Crew Air Transport Pilot (ATP)
Workload; Time Pressure; Distraction; Confusion
Aircraft Equipment Problem Less Severe; Deviation - Altitude Excursion From Assigned Altitude; Deviation - Altitude Overshoot; Deviation / Discrepancy - Procedural Published Material / Policy; Inflight Event / Encounter Loss Of Aircraft Control; Inflight Event / Encounter Weather / Turbulence
Flight Crew Regained Aircraft Control; Flight Crew Took Evasive Action
Procedure; Weather
The First Officer was PF for arrival and planned monitored CAT3 approach for IOE training event exposure. During vectors for arrival; about 20 NM northeast the arrival airport while at 5;000 feet assigned and about 205 knots (200 knots assigned); straight and level flight; clean configuration with autopilot two (AP2) and autothrottle (ATS) on; PF noticed speed decreasing to the foot (190 knots) and queried 'What's going on?' No windshear warning received and only occasional turbulence was encountered during the arrival. No convective weather apparent on the radar during arrival and descent; but heavy rain in the vicinity. Stick shaker activated and speed decreased to about 180 knots. The First Officer disconnected the AP and ATS; selected max power and descended some during the recovery resulting in 'altitude' callouts from the CAWS. Descent was never more than about 350 feet lower than assigned and overshoots to about 200 feet high on recovery. Aircraft gross weight at the time was approximately 370;000 lbs. Wing was clean with no speed brakes extended and we were not turning. Foot was about 190 knots. No limits were exceeded. Aircraft had been previously written up for anomalous stick shaker during climbout at about 190 knots. I would suggest immediate response rather than a query may have started the recovery sooner. Earlier configuration with slats would have increased the margin for minimum safe speed.
About 20 miles from the field we briefly got a stick shaker. The airplane was at 5;000 feet and at 205 knots. There were some rain showers in the area and I noticed a quick drop in airspeed. It seemed as if it was most likely an updraft associated with the weather. I disconnected the automation and immediately increased the speed. We lost somewhere between 300 and 350 feet of altitude in the process. We did not receive windshear warning. The speed dropped to somewhere around 185 knots before recovery. The Captain and I noticed that the stick shaker had been written up previously.
A MD-11 at 5;000 feet; 205 knots with slats extended lost about 300 feet during a windshear airspeed decrease to about 185 knots with a stall warning while on approach in rain.