Narrative:

On final approach to phx runway 26, we conducted the before landing checklist and noticed the leading edge flaps 'green light' was not illuminated and the amber 'transit' light was illuminated. This is consistent with a known discrepancy which was appropriately documented, deferred and placarded in accordance with company MEL procedures. The aft overhead panel indicated that all flap leading edge devices were in fact 'green.' therefore, we continued the visual approach and landing. Landing, rollout, and taxi-in were uneventful. However, the amber light and subsequent verification of the leading edge device status lights on the aft overhead panel proved to be a distraction just about the time we were receiving a landing clearance from the phx ATC. I am almost certain we received and read back the appropriate landing clearance, yet the captain was not sure after the fact and brought this point up on postflt discussion. In retrospect, it is possible we landing without clearance. The 'triggers' that set this discussion in motion include: the captain advised me that he didn't turn on the outboard landing lights (he indicated he uses that as a verification technique). Phx tower seemed confused as to our location on the airport after the landing rollout and exit from the active runway (they eventually directed us to join charlie eastbound and contact north ground). Although there was no indication from the phx ATC personnel as to a possible deviation on the part of either party (ie, no request to call the tower upon arrival), it is still possible we landing without clearance due to the distraction in dealing with the verification of the leading edge device indicators. Human factors involved in this event include a long flight (4 hours 35 mins) and the end of a 4 day morning pairing, early morning wake-up on the east coast (mht) for 2 pilots who live in the mountain standard time zone, and the aforementioned distraction during flap selection in a critical phase of flight. It is always good practice for both pilots to verbally announce the landing clearance, and I have made a habit of doing this based on previous requirements at other carriers. For example, at my last carrier, the 1000 ft callouts went like this: PF --

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Original NASA ASRS Text

Title: A B737-300 FLT CREW CITE THE POSSIBILITY OF A RWY INCURSION AFTER THEY MAY HAVE LWOC ON RWY 26 DURING A NIGHT OP AT PHX, AZ.

Narrative: ON FINAL APCH TO PHX RWY 26, WE CONDUCTED THE BEFORE LNDG CHKLIST AND NOTICED THE LEADING EDGE FLAPS 'GREEN LIGHT' WAS NOT ILLUMINATED AND THE AMBER 'TRANSIT' LIGHT WAS ILLUMINATED. THIS IS CONSISTENT WITH A KNOWN DISCREPANCY WHICH WAS APPROPRIATELY DOCUMENTED, DEFERRED AND PLACARDED IN ACCORDANCE WITH COMPANY MEL PROCS. THE AFT OVERHEAD PANEL INDICATED THAT ALL FLAP LEADING EDGE DEVICES WERE IN FACT 'GREEN.' THEREFORE, WE CONTINUED THE VISUAL APCH AND LNDG. LNDG, ROLLOUT, AND TAXI-IN WERE UNEVENTFUL. HOWEVER, THE AMBER LIGHT AND SUBSEQUENT VERIFICATION OF THE LEADING EDGE DEVICE STATUS LIGHTS ON THE AFT OVERHEAD PANEL PROVED TO BE A DISTR JUST ABOUT THE TIME WE WERE RECEIVING A LNDG CLRNC FROM THE PHX ATC. I AM ALMOST CERTAIN WE RECEIVED AND READ BACK THE APPROPRIATE LNDG CLRNC, YET THE CAPT WAS NOT SURE AFTER THE FACT AND BROUGHT THIS POINT UP ON POSTFLT DISCUSSION. IN RETROSPECT, IT IS POSSIBLE WE LWOC. THE 'TRIGGERS' THAT SET THIS DISCUSSION IN MOTION INCLUDE: THE CAPT ADVISED ME THAT HE DIDN'T TURN ON THE OUTBOARD LNDG LIGHTS (HE INDICATED HE USES THAT AS A VERIFICATION TECHNIQUE). PHX TWR SEEMED CONFUSED AS TO OUR LOCATION ON THE ARPT AFTER THE LNDG ROLLOUT AND EXIT FROM THE ACTIVE RWY (THEY EVENTUALLY DIRECTED US TO JOIN CHARLIE EBOUND AND CONTACT N GND). ALTHOUGH THERE WAS NO INDICATION FROM THE PHX ATC PERSONNEL AS TO A POSSIBLE DEV ON THE PART OF EITHER PARTY (IE, NO REQUEST TO CALL THE TWR UPON ARR), IT IS STILL POSSIBLE WE LWOC DUE TO THE DISTR IN DEALING WITH THE VERIFICATION OF THE LEADING EDGE DEVICE INDICATORS. HUMAN FACTORS INVOLVED IN THIS EVENT INCLUDE A LONG FLT (4 HRS 35 MINS) AND THE END OF A 4 DAY MORNING PAIRING, EARLY MORNING WAKE-UP ON THE EAST COAST (MHT) FOR 2 PLTS WHO LIVE IN THE MOUNTAIN STANDARD TIME ZONE, AND THE AFOREMENTIONED DISTR DURING FLAP SELECTION IN A CRITICAL PHASE OF FLT. IT IS ALWAYS GOOD PRACTICE FOR BOTH PLTS TO VERBALLY ANNOUNCE THE LNDG CLRNC, AND I HAVE MADE A HABIT OF DOING THIS BASED ON PREVIOUS REQUIREMENTS AT OTHER CARRIERS. FOR EXAMPLE, AT MY LAST CARRIER, THE 1000 FT CALLOUTS WENT LIKE THIS: PF --

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