Narrative:

Upon selecting flaps 1 degree for landing; we received the 'leading edge disagreement' light on the forward instrument panel along with the associated EICAS message; 'leading edge slat disagreement.' at that time; I notified ATC we were not ready to commence the approach and I referenced the QRH to perform the 'leading edge slat disagreement -757' procedure. Upon execution of the procedure; the leading edge slats and trailing edge flaps extended normally using the alternate slat/flap system and we commenced the approach and landed. After arriving at the gate; aircraft maintenance was notified and the mechanical discrepancy was entered in the aircraft logbook. While stowing my QRH; it occurred to me that the 'leading edge slat disagreement' procedure is an emergency procedure. With that information; I realized that an emergency should have been declared with ATC for the QRH procedure that I just performed. After further review of the QRH procedure; I determined that I had landed with a flap setting that was greater than what was called for in the given situation; but one that is appropriate for normal slat/flap operations. During this event; by interpreting the procedure incorrectly; and selecting this inappropriate landing flap setting for the given situation; I did not think that declaring an emergency was necessary. As captain; and pilot monitoring; I take full and sole responsibility for all of the errors that occurred during the execution of this procedure. I incorrectly interpreted the QRH procedure; made all of the selections of the associated switches and flap positions; and failed to declare an emergency for the given situation.

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Original NASA ASRS Text

Title: B757 flight crew reports LE SLAT DISAGREE during approach. Crew accomplishes QRH procedure and lands with full flaps and slats using the ALTN FLAP and SLAT selector switches.

Narrative: Upon selecting flaps 1 degree for landing; we received the 'Leading Edge Disagreement' light on the forward instrument panel along with the associated EICAS message; 'Leading Edge Slat Disagreement.' At that time; I notified ATC we were not ready to commence the approach and I referenced the QRH to perform the 'Leading Edge Slat Disagreement -757' procedure. Upon execution of the procedure; the Leading Edge Slats and Trailing Edge Flaps extended normally using the alternate Slat/Flap system and we commenced the approach and landed. After arriving at the gate; aircraft maintenance was notified and the mechanical discrepancy was entered in the aircraft logbook. While stowing my QRH; it occurred to me that the 'Leading Edge Slat Disagreement' procedure is an emergency procedure. With that information; I realized that an emergency should have been declared with ATC for the QRH procedure that I just performed. After further review of the QRH procedure; I determined that I had landed with a flap setting that was greater than what was called for in the given situation; but one that is appropriate for normal slat/flap operations. During this event; by interpreting the procedure incorrectly; and selecting this inappropriate landing flap setting for the given situation; I did not think that declaring an emergency was necessary. As Captain; and Pilot Monitoring; I take full and sole responsibility for all of the errors that occurred during the execution of this procedure. I incorrectly interpreted the QRH procedure; made all of the selections of the associated switches and flap positions; and failed to declare an emergency for the given situation.

Data retrieved from NASA's ASRS site as of April 2012 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.