Narrative:

This is the first time I have made this mistake. After reading all of the previous reports about this, I thought it couldn't happen to me. I was wrong. We were cleared for a visual approach to runway 36L by dfw approach control after the controller referenced traffic we were following as 'a saab 4 mi ahead' (which we did not have in sight, although we had reported the airport in sight). He then told us to slow to 170 KTS to the marker. The captain called for 'flaps 11 degrees' and then 'flaps 15 degrees' in order to slow down. At the same time, the controller started talking to an 'air carrier Y flight' which it sounded like was on a left base for runway 36L. Since we didn't have our traffic in sight, I deliberately delayed switching to tower frequency because I thought the air carrier Y flight was the saab that we were following, and that he was going to turn base to final in front of us. I was trying to gather situational awareness to get the traffic in sight. Next, at least 5 things happened simultaneously. First, we reached the marker. Second, we intercepted the GS. Third, I realized that the air carrier flight was not the saab we were following and that the air carrier Y flight was on a base leg to follow us. Fourth, the captain called for 'gear down' and I focused my attention on finishing the landing checklist and making required callouts. Fifth, I saw the saab inside the airfield boundary just short of the runway. I was concerned that the saab might not clear the runway before we landed, so I was monitoring him (he was hard to see) as well as scanning the entire length of the runway for crossing traffic. The first time we realized we had not switched to tower frequency was after we cleared the runway. We were monitoring 121.5 on VHF #2. At no time did we hear any xmissions on that frequency, if that is relevant. I was the PNF and was responsible for working the radios, therefore the failure to switch to tower frequency was entirely my fault. The approach controller did his job in a perfectly professional manner, as did the captain. They were not responsible for my mistake in any way. It was simply my fault, period. Having said that, I feel that a few words of explanation would be prudent in the interest of safety. I remember a presentation at my air carrier's ground school that depicted the multiple 'layers of protection' in our flying procedures as slices of swiss cheese. The philosophy was that with enough layers in place, hopefully the holes could not line up and allow something to fall all the way through. Great philosophy. The point here is that there have been enough occurrences of this same problem to clearly indicate that this is an area where something is continually falling all the way through. It is apparent that there simply are not enough layers of protection to prevent people from inadvertently landing without clearance following a visual approach. Under certain circumstances, that could certainly be disastrous. Under current procedures, the approach controller is not required to tell us to switch to tower frequency after clearing us for a visual approach. Switching frequencys while airborne without being handed off is certainly an unusual occurrence in the IFR flying environment that we experience in part 121 operations. I would say that, within the context of our normal environment, that qualifies as a very non-standard procedure. As I described above, all of this takes place during a very critical phase of flight, within 1500 ft of the ground when numerous critical tasks are being performed simultaneously. What would be so difficult about changing the controller's procedures to require them to say 'contact the tower,' ie, use the standard handoff procedure to remind us, when they are finished talking to us? That would provide a final layer of protection while we are doing other things like intercepting the localizer, intercepting the GS, changing configns, changing airspds, changing radio frequencys, monitoring crossing altitudes, looking for traffic, making callouts, visually clearing the runway, correcting for xwinds, watching for windshear, and landing an airplane. I am not a controller and I realize that they may have valid reasons for the current procedure, but we sure could use their help if it is available.

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Original NASA ASRS Text

Title: AN MD80 FLT CREW LANDS AT DFW WITHOUT A CLRNC.

Narrative: THIS IS THE FIRST TIME I HAVE MADE THIS MISTAKE. AFTER READING ALL OF THE PREVIOUS RPTS ABOUT THIS, I THOUGHT IT COULDN'T HAPPEN TO ME. I WAS WRONG. WE WERE CLRED FOR A VISUAL APCH TO RWY 36L BY DFW APCH CTL AFTER THE CTLR REFED TFC WE WERE FOLLOWING AS 'A SAAB 4 MI AHEAD' (WHICH WE DID NOT HAVE IN SIGHT, ALTHOUGH WE HAD RPTED THE ARPT IN SIGHT). HE THEN TOLD US TO SLOW TO 170 KTS TO THE MARKER. THE CAPT CALLED FOR 'FLAPS 11 DEGS' AND THEN 'FLAPS 15 DEGS' IN ORDER TO SLOW DOWN. AT THE SAME TIME, THE CTLR STARTED TALKING TO AN 'ACR Y FLT' WHICH IT SOUNDED LIKE WAS ON A L BASE FOR RWY 36L. SINCE WE DIDN'T HAVE OUR TFC IN SIGHT, I DELIBERATELY DELAYED SWITCHING TO TWR FREQ BECAUSE I THOUGHT THE ACR Y FLT WAS THE SAAB THAT WE WERE FOLLOWING, AND THAT HE WAS GOING TO TURN BASE TO FINAL IN FRONT OF US. I WAS TRYING TO GATHER SITUATIONAL AWARENESS TO GET THE TFC IN SIGHT. NEXT, AT LEAST 5 THINGS HAPPENED SIMULTANEOUSLY. FIRST, WE REACHED THE MARKER. SECOND, WE INTERCEPTED THE GS. THIRD, I REALIZED THAT THE ACR FLT WAS NOT THE SAAB WE WERE FOLLOWING AND THAT THE ACR Y FLT WAS ON A BASE LEG TO FOLLOW US. FOURTH, THE CAPT CALLED FOR 'GEAR DOWN' AND I FOCUSED MY ATTN ON FINISHING THE LNDG CHKLIST AND MAKING REQUIRED CALLOUTS. FIFTH, I SAW THE SAAB INSIDE THE AIRFIELD BOUNDARY JUST SHORT OF THE RWY. I WAS CONCERNED THAT THE SAAB MIGHT NOT CLR THE RWY BEFORE WE LANDED, SO I WAS MONITORING HIM (HE WAS HARD TO SEE) AS WELL AS SCANNING THE ENTIRE LENGTH OF THE RWY FOR XING TFC. THE FIRST TIME WE REALIZED WE HAD NOT SWITCHED TO TWR FREQ WAS AFTER WE CLRED THE RWY. WE WERE MONITORING 121.5 ON VHF #2. AT NO TIME DID WE HEAR ANY XMISSIONS ON THAT FREQ, IF THAT IS RELEVANT. I WAS THE PNF AND WAS RESPONSIBLE FOR WORKING THE RADIOS, THEREFORE THE FAILURE TO SWITCH TO TWR FREQ WAS ENTIRELY MY FAULT. THE APCH CTLR DID HIS JOB IN A PERFECTLY PROFESSIONAL MANNER, AS DID THE CAPT. THEY WERE NOT RESPONSIBLE FOR MY MISTAKE IN ANY WAY. IT WAS SIMPLY MY FAULT, PERIOD. HAVING SAID THAT, I FEEL THAT A FEW WORDS OF EXPLANATION WOULD BE PRUDENT IN THE INTEREST OF SAFETY. I REMEMBER A PRESENTATION AT MY ACR'S GND SCHOOL THAT DEPICTED THE MULTIPLE 'LAYERS OF PROTECTION' IN OUR FLYING PROCS AS SLICES OF SWISS CHEESE. THE PHILOSOPHY WAS THAT WITH ENOUGH LAYERS IN PLACE, HOPEFULLY THE HOLES COULD NOT LINE UP AND ALLOW SOMETHING TO FALL ALL THE WAY THROUGH. GREAT PHILOSOPHY. THE POINT HERE IS THAT THERE HAVE BEEN ENOUGH OCCURRENCES OF THIS SAME PROB TO CLRLY INDICATE THAT THIS IS AN AREA WHERE SOMETHING IS CONTINUALLY FALLING ALL THE WAY THROUGH. IT IS APPARENT THAT THERE SIMPLY ARE NOT ENOUGH LAYERS OF PROTECTION TO PREVENT PEOPLE FROM INADVERTENTLY LNDG WITHOUT CLRNC FOLLOWING A VISUAL APCH. UNDER CERTAIN CIRCUMSTANCES, THAT COULD CERTAINLY BE DISASTROUS. UNDER CURRENT PROCS, THE APCH CTLR IS NOT REQUIRED TO TELL US TO SWITCH TO TWR FREQ AFTER CLRING US FOR A VISUAL APCH. SWITCHING FREQS WHILE AIRBORNE WITHOUT BEING HANDED OFF IS CERTAINLY AN UNUSUAL OCCURRENCE IN THE IFR FLYING ENVIRONMENT THAT WE EXPERIENCE IN PART 121 OPS. I WOULD SAY THAT, WITHIN THE CONTEXT OF OUR NORMAL ENVIRONMENT, THAT QUALIFIES AS A VERY NON-STANDARD PROC. AS I DESCRIBED ABOVE, ALL OF THIS TAKES PLACE DURING A VERY CRITICAL PHASE OF FLT, WITHIN 1500 FT OF THE GND WHEN NUMEROUS CRITICAL TASKS ARE BEING PERFORMED SIMULTANEOUSLY. WHAT WOULD BE SO DIFFICULT ABOUT CHANGING THE CTLR'S PROCS TO REQUIRE THEM TO SAY 'CONTACT THE TWR,' IE, USE THE STANDARD HDOF PROC TO REMIND US, WHEN THEY ARE FINISHED TALKING TO US? THAT WOULD PROVIDE A FINAL LAYER OF PROTECTION WHILE WE ARE DOING OTHER THINGS LIKE INTERCEPTING THE LOC, INTERCEPTING THE GS, CHANGING CONFIGNS, CHANGING AIRSPDS, CHANGING RADIO FREQS, MONITORING XING ALTS, LOOKING FOR TFC, MAKING CALLOUTS, VISUALLY CLRING THE RWY, CORRECTING FOR XWINDS, WATCHING FOR WINDSHEAR, AND LNDG AN AIRPLANE. I AM NOT A CTLR AND I REALIZE THAT THEY MAY HAVE VALID REASONS FOR THE CURRENT PROC, BUT WE SURE COULD USE THEIR HELP IF IT IS AVAILABLE.

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.