Narrative:

The first officer was flying the aircraft and the captain was the pm. At 24000 ft; in descent into ZZZ airport (about 70 mi from airport) the first officer inexplicably turned off all hydraulic pumps in the aircraft; putting the aircraft into manual reversion. The aircraft was already in an abnormally nose low attitude; and nose down attitude was increased after his actions. All hydraulic pumps were turned off by the first officer in a rushed and unverbalized action while the captain was involved in other duties talking on the radio and referring to various airport charts. The first officer did not make any effort to coordinate or verify his actions with his fellow crew member. Therefore; the captain was completely unaware of the quadruple hydraulic pump failure. The first officer mistakenly thought he was turning off the engine anti-ice switches; and additionally canceled the master caution warning without notifying the captain of that action; under a further mistaken idea that the master caution had some relation to the anti-ice switches. When the aircraft reached an alarming nose-down attitude; the captain took control of the aircraft (while still unaware of the hydraulic failure). The captain immediately recognized the manual reversion situation when attempting to recover the aircraft and discovered all 4 hydraulic pumps in the off position. The first officer at this point also pulling back on the control wheel with considerable force; so when the hydraulic pumps were turned on (and the captain released pressure on the control column) the first officer did not release the column and a stronger than normal pull-up resulted when all pumps were turned back on. The strong pull-up resulted in no passenger injuries; however; 2 flight attendants were knocked to the floor and injured. 1 flight attendant was only injured slightly; and the other flight attendant injured her arm; but was able to continue on the next flight. Additional training for the first officer to be more careful what switches he turns off and on; and to not do so in a manner that is unnoticeable to the captain. Supplemental information from acn 765246: we broke out below the clouds and I thought I turned the engine heat back off (left hydraulic pumps actually); I glanced up to check that the valves had closed and noticed that the lights illuminated to the left of my hand and I proceeded to turn off the engine anti-ice (right hydraulic pumps). In the seconds to follow I thought I lost my VNAV path as I was now cleared to 11000 ft. The airplane was now absent hydraulics and was nosing down and accelerating. I was concerned about getting my VNAV path back as the captain quickly and accurately recognized a flight control problem and he punched off the autoplt. In the process of simultaneously manually raising the pitch and turning the hydraulics back on; I induced a moderate turbulence. I will never move an overhead switch again without first confirming visually I have indeed grabbed the correct switches.

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Original NASA ASRS Text

Title: A B737 PLT ATTEMPTING TO CLOSE ENG ANTI-ICE VALVES MISTAKENLY TURNED OFF ALL HYD PWR. FLT ATTENDANT INJURIES RESULTED WHEN HYD PWR RESTORED.

Narrative: THE FO WAS FLYING THE ACFT AND THE CAPT WAS THE PM. AT 24000 FT; IN DSCNT INTO ZZZ ARPT (ABOUT 70 MI FROM ARPT) THE FO INEXPLICABLY TURNED OFF ALL HYD PUMPS IN THE ACFT; PUTTING THE ACFT INTO MANUAL REVERSION. THE ACFT WAS ALREADY IN AN ABNORMALLY NOSE LOW ATTITUDE; AND NOSE DOWN ATTITUDE WAS INCREASED AFTER HIS ACTIONS. ALL HYD PUMPS WERE TURNED OFF BY THE FO IN A RUSHED AND UNVERBALIZED ACTION WHILE THE CAPT WAS INVOLVED IN OTHER DUTIES TALKING ON THE RADIO AND REFERRING TO VARIOUS ARPT CHARTS. THE FO DID NOT MAKE ANY EFFORT TO COORDINATE OR VERIFY HIS ACTIONS WITH HIS FELLOW CREW MEMBER. THEREFORE; THE CAPT WAS COMPLETELY UNAWARE OF THE QUADRUPLE HYD PUMP FAILURE. THE FO MISTAKENLY THOUGHT HE WAS TURNING OFF THE ENG ANTI-ICE SWITCHES; AND ADDITIONALLY CANCELED THE MASTER CAUTION WARNING WITHOUT NOTIFYING THE CAPT OF THAT ACTION; UNDER A FURTHER MISTAKEN IDEA THAT THE MASTER CAUTION HAD SOME RELATION TO THE ANTI-ICE SWITCHES. WHEN THE ACFT REACHED AN ALARMING NOSE-DOWN ATTITUDE; THE CAPT TOOK CTL OF THE ACFT (WHILE STILL UNAWARE OF THE HYD FAILURE). THE CAPT IMMEDIATELY RECOGNIZED THE MANUAL REVERSION SITUATION WHEN ATTEMPTING TO RECOVER THE ACFT AND DISCOVERED ALL 4 HYD PUMPS IN THE OFF POS. THE FO AT THIS POINT ALSO PULLING BACK ON THE CTL WHEEL WITH CONSIDERABLE FORCE; SO WHEN THE HYD PUMPS WERE TURNED ON (AND THE CAPT RELEASED PRESSURE ON THE CTL COLUMN) THE FO DID NOT RELEASE THE COLUMN AND A STRONGER THAN NORMAL PULL-UP RESULTED WHEN ALL PUMPS WERE TURNED BACK ON. THE STRONG PULL-UP RESULTED IN NO PAX INJURIES; HOWEVER; 2 FLT ATTENDANTS WERE KNOCKED TO THE FLOOR AND INJURED. 1 FLT ATTENDANT WAS ONLY INJURED SLIGHTLY; AND THE OTHER FLT ATTENDANT INJURED HER ARM; BUT WAS ABLE TO CONTINUE ON THE NEXT FLT. ADDITIONAL TRAINING FOR THE FO TO BE MORE CAREFUL WHAT SWITCHES HE TURNS OFF AND ON; AND TO NOT DO SO IN A MANNER THAT IS UNNOTICEABLE TO THE CAPT. SUPPLEMENTAL INFO FROM ACN 765246: WE BROKE OUT BELOW THE CLOUDS AND I THOUGHT I TURNED THE ENG HEAT BACK OFF (L HYD PUMPS ACTUALLY); I GLANCED UP TO CHK THAT THE VALVES HAD CLOSED AND NOTICED THAT THE LIGHTS ILLUMINATED TO THE L OF MY HAND AND I PROCEEDED TO TURN OFF THE ENG ANTI-ICE (R HYD PUMPS). IN THE SECONDS TO FOLLOW I THOUGHT I LOST MY VNAV PATH AS I WAS NOW CLRED TO 11000 FT. THE AIRPLANE WAS NOW ABSENT HYDS AND WAS NOSING DOWN AND ACCELERATING. I WAS CONCERNED ABOUT GETTING MY VNAV PATH BACK AS THE CAPT QUICKLY AND ACCURATELY RECOGNIZED A FLT CTL PROB AND HE PUNCHED OFF THE AUTOPLT. IN THE PROCESS OF SIMULTANEOUSLY MANUALLY RAISING THE PITCH AND TURNING THE HYDS BACK ON; I INDUCED A MODERATE TURB. I WILL NEVER MOVE AN OVERHEAD SWITCH AGAIN WITHOUT FIRST CONFIRMING VISUALLY I HAVE INDEED GRABBED THE CORRECT SWITCHES.

Data retrieved from NASA's ASRS site as of January 2009 and automatically converted to unabbreviated mixed upper/lowercase text. This report is for informational purposes with no guarantee of accuracy. See NASA's ASRS site for official report.