Narrative:

Evening crew brought over aircraft approximately XA00. I; along with 2 other mechanics; finished pre-dock functions; put the airplane in hangar; and helped hook up ground power by XB00; at which time the mechanics began the scheduled 'C' check. As I was walking by the nose of the aircraft at approximately XB30; a mechanic asked if anyone was in the cockpit. I asked him what he needed. He replied that the leads wanted the flaps out electric. I said that I would go up if a lead would clear the aircraft. A lead gave me the thumbs up; visually; as I waited at the forward entry door. I entered the cockpit and checked to make sure the standby rudder breaker was out and collared. I set the alternate flap switch to standby; listened for standby pump to not start. I set up/down switch to 'down.' I monitored flap indicator as flap trailing edge moved towards 1 degree. I moved the flap handle from 0 degrees to 40 degrees to relieve tension on flap motor. When I heard a noise like a large ladder falling to the floor; I immediately: 1) set the up/down switch to 'off;' 2) switched the alternate flap switch off; 3) moved the flap handle to 1 degree to match flap position; 4) heard someone yell to turn hydraulics off and immediately did so. The kruger flaps deployed and damaged the inboard core cowls on #1 and #2 engines.

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Original NASA ASRS Text

Title: A B737-300 INCURRED DAMAGE TO THE INBOARD COWLING ON #1 AND #2 ENGS WHEN THE LEADING EDGE DEVICES WERE EXTENDED WITH THE ENG COWLING OPEN.

Narrative: EVENING CREW BROUGHT OVER ACFT APPROX XA00. I; ALONG WITH 2 OTHER MECHS; FINISHED PRE-DOCK FUNCTIONS; PUT THE AIRPLANE IN HANGAR; AND HELPED HOOK UP GND PWR BY XB00; AT WHICH TIME THE MECHS BEGAN THE SCHEDULED 'C' CHK. AS I WAS WALKING BY THE NOSE OF THE ACFT AT APPROX XB30; A MECH ASKED IF ANYONE WAS IN THE COCKPIT. I ASKED HIM WHAT HE NEEDED. HE REPLIED THAT THE LEADS WANTED THE FLAPS OUT ELECTRIC. I SAID THAT I WOULD GO UP IF A LEAD WOULD CLR THE ACFT. A LEAD GAVE ME THE THUMBS UP; VISUALLY; AS I WAITED AT THE FORWARD ENTRY DOOR. I ENTERED THE COCKPIT AND CHKED TO MAKE SURE THE STANDBY RUDDER BREAKER WAS OUT AND COLLARED. I SET THE ALTERNATE FLAP SWITCH TO STANDBY; LISTENED FOR STANDBY PUMP TO NOT START. I SET UP/DOWN SWITCH TO 'DOWN.' I MONITORED FLAP INDICATOR AS FLAP TRAILING EDGE MOVED TOWARDS 1 DEG. I MOVED THE FLAP HANDLE FROM 0 DEGS TO 40 DEGS TO RELIEVE TENSION ON FLAP MOTOR. WHEN I HEARD A NOISE LIKE A LARGE LADDER FALLING TO THE FLOOR; I IMMEDIATELY: 1) SET THE UP/DOWN SWITCH TO 'OFF;' 2) SWITCHED THE ALTERNATE FLAP SWITCH OFF; 3) MOVED THE FLAP HANDLE TO 1 DEG TO MATCH FLAP POS; 4) HEARD SOMEONE YELL TO TURN HYDS OFF AND IMMEDIATELY DID SO. THE KRUGER FLAPS DEPLOYED AND DAMAGED THE INBOARD CORE COWLS ON #1 AND #2 ENGS.

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.