Narrative:

During climb through 26800' in moderate turbulence and icing conditions, I was on the P/a advising passenger of turbulence. As I returned from the P/a I first noticed the annunciator flight control light illuminated followed by low hydraulic system B pressure. I advised the captain and suggested the checklist. He replied 'request 26000',' and accomplished the appropriate checklist. As I was accomplishing the checklist I heard the altitude horn and observed that our altitude appeared to be 200-300' low and advised the captain. He corrected and flight resumed. The captain had determined during the course he had turned off the hydraulic B pumps (electric) instead of the engine anti-ice valve control switches, which are located directly above the B pumps and are the same type switches. I recommend the switch knobs on either system be replaced with a different shape. Callback conversation with reporter revealed the following: reporter advised type of aircraft and that on the later models presently being built, the problem has been resolved. Is not a general problem as far as he knows, but has heard other flight crew have done the same thing. Suggests a guard be placed over the B pumps in the on position. Feels strongly the condition could be corrected relatively easily.

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Original NASA ASRS Text

Title: LOST B HYDRAULIC SYSTEM WHEN CAPT INADVERTENTLY TURNED OFF B ELECTRIC SWITCHES WHEN HE WAS ATTEMPTING TO DEACTIVATE ENGINE ANTI ICE SYSTEM.

Narrative: DURING CLB THROUGH 26800' IN MODERATE TURB AND ICING CONDITIONS, I WAS ON THE P/A ADVISING PAX OF TURB. AS I RETURNED FROM THE P/A I FIRST NOTICED THE ANNUNCIATOR FLT CONTROL LIGHT ILLUMINATED FOLLOWED BY LOW HYD SYS B PRESSURE. I ADVISED THE CAPT AND SUGGESTED THE CHKLIST. HE REPLIED 'REQUEST 26000',' AND ACCOMPLISHED THE APPROPRIATE CHKLIST. AS I WAS ACCOMPLISHING THE CHKLIST I HEARD THE ALT HORN AND OBSERVED THAT OUR ALT APPEARED TO BE 200-300' LOW AND ADVISED THE CAPT. HE CORRECTED AND FLT RESUMED. THE CAPT HAD DETERMINED DURING THE COURSE HE HAD TURNED OFF THE HYD B PUMPS (ELECTRIC) INSTEAD OF THE ENG ANTI-ICE VALVE CTL SWITCHES, WHICH ARE LOCATED DIRECTLY ABOVE THE B PUMPS AND ARE THE SAME TYPE SWITCHES. I RECOMMEND THE SWITCH KNOBS ON EITHER SYS BE REPLACED WITH A DIFFERENT SHAPE. CALLBACK CONVERSATION WITH RPTR REVEALED THE FOLLOWING: RPTR ADVISED TYPE OF ACFT AND THAT ON THE LATER MODELS PRESENTLY BEING BUILT, THE PROB HAS BEEN RESOLVED. IS NOT A GENERAL PROB AS FAR AS HE KNOWS, BUT HAS HEARD OTHER FLT CREW HAVE DONE THE SAME THING. SUGGESTS A GUARD BE PLACED OVER THE B PUMPS IN THE ON POS. FEELS STRONGLY THE CONDITION COULD BE CORRECTED RELATIVELY EASILY.

Data retrieved from NASA's ASRS site as of August 2007 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.