Narrative:

FL330; 255 KIAS. I was the captain/pilot monitoring and was reaching down to get an advanced ATIS and field conditions report via ACARS. Just as my hand was coming up to the CDU; ATC issued a direct clearance. Since my hand was already on the CDU; I told the first officer (PF) that I would input the course change to the FMC; and acknowledged the clearance with center. The PF verified the change; which I then executed. As I was leaning back into my seat and retracting my hand back and up from manipulating the CDU; I accidentally and inadvertently brushed the flap lever with the fleshy part of my thumb where it joins the wrist. The flap lever must not have been fully seated; as it moved to flap position 1. I never felt the flap lever or noticed that it had moved. We felt aerodynamic buffet; and my first thought was that we had a mach overspeed or had encountered an unforecast mountain wave. I immediately moved my hands to the throttles and looked at the airspeed indicator. The PF said something to the effect of; 'you extended the flaps;' and immediately put the flap lever to the up position. The trailing edge flaps had moved quickly and symmetrically to flaps 1 degree; and we noted an amber leading edge flaps transit light. As soon as the flap handle was repositioned to flaps up; the trailing edge flaps moved to up and the leading edge flaps transit light extinguished. The overhead leading edge devices annunciator panel showed all leading edge flaps and slats fully retracted. We estimate that the flap handle was out of the up position for approximately 5 seconds. It was only due to the PF's attention and the fact that we were in the process of coordinating the course change (both pilots were fully engaged in operating the aircraft) that the flap handle was out of the correct position for such a short period of time. The 'B' autoplt was engaged the entire time; and there was no roll or yaw. After the flaps retracted; the buffet ceased. We referred to the QRH to see if any of the flap checklists (and notes) could provide us with any guidance. We immediately ACARS'ed dispatch to notify them of the flap 1 degree overspeed and that I had inadvertently violated the airframe limitation of extending the flaps above FL200. We wanted to arrange for maintenance to inspect the aircraft. We exchanged numerous messages with dispatch/maintenance control. During confign for the landing; we paused at flap position 1 degree; 2 degrees; 5 degrees; 10 degrees 15 degrees; 25 degrees; and 30 degrees and noted all forward and overhead indications normal; with no roll. After landing; the flap retraction was normal. On the ground; I coordination a logbook entry with dispatch/maintenance control. Maintenance inspected the aircraft; cleared the logbook entry; and returned the aircraft to service. I also talked to an assistant chief pilot before making the logbook entry. He called our system chief pilot for further confirmation that it was ok to continue the sequence; and to get a second opinion verifying that we had addressed all conceivable issues. We departed 5 mins late for an uneventful flight to our destination. Believe me; this was an inadvertent error on my part; for which I am truly embarrassed. I want to thank my first officer; dispatch; maintenance; and flight operations management pilots for their support and professional assistance. 1) know where your hands are! This is the first time I have inadvertently actuated a cockpit control and I am going to make sure it is the last time. 2) make sure the flap handle is positively seated in each position. The flap handle and throttles on this 300 were very stiff; which should have cued me to verify that the flap handle was fully seated in the up position. When fully seated; the flap handle should not move when it is merely brushed by either pilot. I do not know if this type of incident has happened before in our classic fleet; but I can assure you that is possible for it to happen again. Even a very conscientious pilot can make this error. I would venture to say that this combined human factors/human engineering error has never occurred in the newer fleet types.

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Original NASA ASRS Text

Title: B737 FLT CREW REPORTS INADVERTENT FLAP EXTENSION IN CRUISE AT FL330.

Narrative: FL330; 255 KIAS. I WAS THE CAPT/PLT MONITORING AND WAS REACHING DOWN TO GET AN ADVANCED ATIS AND FIELD CONDITIONS RPT VIA ACARS. JUST AS MY HAND WAS COMING UP TO THE CDU; ATC ISSUED A DIRECT CLRNC. SINCE MY HAND WAS ALREADY ON THE CDU; I TOLD THE FO (PF) THAT I WOULD INPUT THE COURSE CHANGE TO THE FMC; AND ACKNOWLEDGED THE CLRNC WITH CTR. THE PF VERIFIED THE CHANGE; WHICH I THEN EXECUTED. AS I WAS LEANING BACK INTO MY SEAT AND RETRACTING MY HAND BACK AND UP FROM MANIPULATING THE CDU; I ACCIDENTALLY AND INADVERTENTLY BRUSHED THE FLAP LEVER WITH THE FLESHY PART OF MY THUMB WHERE IT JOINS THE WRIST. THE FLAP LEVER MUST NOT HAVE BEEN FULLY SEATED; AS IT MOVED TO FLAP POS 1. I NEVER FELT THE FLAP LEVER OR NOTICED THAT IT HAD MOVED. WE FELT AERODYNAMIC BUFFET; AND MY FIRST THOUGHT WAS THAT WE HAD A MACH OVERSPEED OR HAD ENCOUNTERED AN UNFORECAST MOUNTAIN WAVE. I IMMEDIATELY MOVED MY HANDS TO THE THROTTLES AND LOOKED AT THE AIRSPD INDICATOR. THE PF SAID SOMETHING TO THE EFFECT OF; 'YOU EXTENDED THE FLAPS;' AND IMMEDIATELY PUT THE FLAP LEVER TO THE UP POS. THE TRAILING EDGE FLAPS HAD MOVED QUICKLY AND SYMMETRICALLY TO FLAPS 1 DEG; AND WE NOTED AN AMBER LEADING EDGE FLAPS TRANSIT LIGHT. AS SOON AS THE FLAP HANDLE WAS REPOSITIONED TO FLAPS UP; THE TRAILING EDGE FLAPS MOVED TO UP AND THE LEADING EDGE FLAPS TRANSIT LIGHT EXTINGUISHED. THE OVERHEAD LEADING EDGE DEVICES ANNUNCIATOR PANEL SHOWED ALL LEADING EDGE FLAPS AND SLATS FULLY RETRACTED. WE ESTIMATE THAT THE FLAP HANDLE WAS OUT OF THE UP POS FOR APPROX 5 SECONDS. IT WAS ONLY DUE TO THE PF'S ATTN AND THE FACT THAT WE WERE IN THE PROCESS OF COORDINATING THE COURSE CHANGE (BOTH PLTS WERE FULLY ENGAGED IN OPERATING THE ACFT) THAT THE FLAP HANDLE WAS OUT OF THE CORRECT POS FOR SUCH A SHORT PERIOD OF TIME. THE 'B' AUTOPLT WAS ENGAGED THE ENTIRE TIME; AND THERE WAS NO ROLL OR YAW. AFTER THE FLAPS RETRACTED; THE BUFFET CEASED. WE REFERRED TO THE QRH TO SEE IF ANY OF THE FLAP CHKLISTS (AND NOTES) COULD PROVIDE US WITH ANY GUIDANCE. WE IMMEDIATELY ACARS'ED DISPATCH TO NOTIFY THEM OF THE FLAP 1 DEG OVERSPEED AND THAT I HAD INADVERTENTLY VIOLATED THE AIRFRAME LIMITATION OF EXTENDING THE FLAPS ABOVE FL200. WE WANTED TO ARRANGE FOR MAINT TO INSPECT THE ACFT. WE EXCHANGED NUMEROUS MESSAGES WITH DISPATCH/MAINT CTL. DURING CONFIGN FOR THE LNDG; WE PAUSED AT FLAP POS 1 DEG; 2 DEGS; 5 DEGS; 10 DEGS 15 DEGS; 25 DEGS; AND 30 DEGS AND NOTED ALL FORWARD AND OVERHEAD INDICATIONS NORMAL; WITH NO ROLL. AFTER LNDG; THE FLAP RETRACTION WAS NORMAL. ON THE GND; I COORD A LOGBOOK ENTRY WITH DISPATCH/MAINT CTL. MAINT INSPECTED THE ACFT; CLRED THE LOGBOOK ENTRY; AND RETURNED THE ACFT TO SVC. I ALSO TALKED TO AN ASSISTANT CHIEF PLT BEFORE MAKING THE LOGBOOK ENTRY. HE CALLED OUR SYS CHIEF PLT FOR FURTHER CONFIRMATION THAT IT WAS OK TO CONTINUE THE SEQUENCE; AND TO GET A SECOND OPINION VERIFYING THAT WE HAD ADDRESSED ALL CONCEIVABLE ISSUES. WE DEPARTED 5 MINS LATE FOR AN UNEVENTFUL FLT TO OUR DEST. BELIEVE ME; THIS WAS AN INADVERTENT ERROR ON MY PART; FOR WHICH I AM TRULY EMBARRASSED. I WANT TO THANK MY FO; DISPATCH; MAINT; AND FLT OPS MGMNT PLTS FOR THEIR SUPPORT AND PROFESSIONAL ASSISTANCE. 1) KNOW WHERE YOUR HANDS ARE! THIS IS THE FIRST TIME I HAVE INADVERTENTLY ACTUATED A COCKPIT CTL AND I AM GOING TO MAKE SURE IT IS THE LAST TIME. 2) MAKE SURE THE FLAP HANDLE IS POSITIVELY SEATED IN EACH POS. THE FLAP HANDLE AND THROTTLES ON THIS 300 WERE VERY STIFF; WHICH SHOULD HAVE CUED ME TO VERIFY THAT THE FLAP HANDLE WAS FULLY SEATED IN THE UP POS. WHEN FULLY SEATED; THE FLAP HANDLE SHOULD NOT MOVE WHEN IT IS MERELY BRUSHED BY EITHER PLT. I DO NOT KNOW IF THIS TYPE OF INCIDENT HAS HAPPENED BEFORE IN OUR CLASSIC FLEET; BUT I CAN ASSURE YOU THAT IS POSSIBLE FOR IT TO HAPPEN AGAIN. EVEN A VERY CONSCIENTIOUS PLT CAN MAKE THIS ERROR. I WOULD VENTURE TO SAY THAT THIS COMBINED HUMAN FACTORS/HUMAN ENGINEERING ERROR HAS NEVER OCCURRED IN THE NEWER FLEET TYPES.

Data retrieved from NASA's ASRS site as of May 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.