Narrative:

Our event started with receipt of the flight release which had a D maintenance item which stated right aileron trim needed for landing. No logbook reference was available to determine how much trim was needed so we had to trust that the previous trim problem was within maintenance deferral limits. It was my turn to fly. We had a direct crosswind upon landing and we were very busy on the short leg. I did not notice how much; if any; right aileron trim I was using after flap extension. On the next leg; the captain flew. He noticed significant right aileron trim was needed after extending flaps for landing. On the landing rollout; the automatic spoilers only extended 1/2 way and subsequently generated an automatic speed brake caution message. At the gate; the captain entered the maintenance discrepancy into the logbook. Per normal procedures; the frm was consulted when completing the logbook entry. The captain showed me that one of the first questions the frm asked regarding the speed brake deferral -- was there significant airplane roll? This frm question introduced us to the possibility that the roll we experienced on landing could be associated with spoiler float. This left a question in both our minds as to whether or not the aileron trim deferral and the automatic speed brake issue could possibly be related. My captain consulted with maintenance and the resulting write-up detailed the automatic spoiler problem and also included detail of the possibility of spoiler float. As luck would have it; our outbound flight was assigned to the same aircraft. Our expectations were for maintenance to address our concern of spoiler float. Upon receiving the flight release we noticed that the only obvious maintenance action was that they deferred the automatic speed brakes. This did not adequately address the spoiler float issue; so we then brought this to the attention of the chief pilot on duty. During a conference call with the chief pilot and maintenance; we learned that the initial trim write-up occurred late april and specified that 2 units of aileron trim were needed by the crew and noted in the write-up. We also learned that 2 units was the maximum amount of trim allowed to defer per the associated maintenance procedure. We proceeded to the airplane to have a face-to-face with maintenance and determine if they tested for the possibility of spoiler float. They had not; so we requested that an acp come to the airplane. The acp did not think spoiler float was a concern. According to him; if it was spoiler float; we would have received a spoiler caution message. Since the roll occurred when flaps were extended past 20 degrees (per previous write-up; I am not sure what flap setting introduced the roll) he believed it could be a problem with the leading edge slats extending for landing. The acp said time did not allow for them to check the spoilers and that if we flew it to ZZZ they would check the spoilers there. The captain and I discussed our comfort level with the airplane. Considering the urging of the acp; the fact that we flew the airplane inbound and knew what to expect upon landing and that we could not definitely prove it was a spoiler float problem; we accepted the airplane. As a side note; maintenance made repeated mention that we should have been provided with a paper to document trim settings for each flight leg; he believed this was part of the deferral. We explained to him that we did not receive this paperwork and then he said it isn't required for each leg. Upon landing (my leg); the captain noted the aileron trim required was between 2 and 4 units and for the most part steady at 3 units. This information was then entered into the logbook. After speaking with maintenance upon deplaning; we learned that 3 unit displacement allows deferral for a 30 day period and their intentions were to turn this airplane outbound with that new deferral. This gave me the impression that they were not going to check for spoiler float as promised by the chief pilot. My captain then contacted the union to discuss our concerns and later briefed me that the airplane had been removed from service. In summary; I have 3 concerns with the events that occurred: the aileron trim deferral provided us with no specific information as to the amount of trim required; we had no way of referencing the previous write-up. I understand the maintenance manual was written by people with exponentially more B757 knowledge than myself. However; I believe that a significant requirement for aileron trim should not be allowed to be deferred. Low level roll is never a desirable trait of an airplane I fly. When armed with specific knowledge of past write-ups the normal approach and landing was manageable. I would be concerned that if this problem existed with some type of engine malfunction; control inputs required would be those that crews have not been subjected to in simulator training (I've never had a simulator session with engine out procedures and aileron trim requirements upon flap extension). Lastly; the frm referenced the possibility of spoiler float; and because of that; we entered that information into the logbook. We were disappointed that the airplane was returned to service without at least verifying the proper operation of the spoilers.

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Original NASA ASRS Text

Title: B757 FLT CREW ACCEPTS ACFT WITH MEL FOR ROLL INDUCED AS FLAPS ARE EXTENDED FOR LANDING; REQUIRING 2 UNITS OF AILERON TRIM.

Narrative: OUR EVENT STARTED WITH RECEIPT OF THE FLT RELEASE WHICH HAD A D MAINT ITEM WHICH STATED R AILERON TRIM NEEDED FOR LNDG. NO LOGBOOK REF WAS AVAILABLE TO DETERMINE HOW MUCH TRIM WAS NEEDED SO WE HAD TO TRUST THAT THE PREVIOUS TRIM PROB WAS WITHIN MAINT DEFERRAL LIMITS. IT WAS MY TURN TO FLY. WE HAD A DIRECT XWIND UPON LNDG AND WE WERE VERY BUSY ON THE SHORT LEG. I DID NOT NOTICE HOW MUCH; IF ANY; R AILERON TRIM I WAS USING AFTER FLAP EXTENSION. ON THE NEXT LEG; THE CAPT FLEW. HE NOTICED SIGNIFICANT R AILERON TRIM WAS NEEDED AFTER EXTENDING FLAPS FOR LNDG. ON THE LNDG ROLLOUT; THE AUTO SPOILERS ONLY EXTENDED 1/2 WAY AND SUBSEQUENTLY GENERATED AN AUTO SPD BRAKE CAUTION MESSAGE. AT THE GATE; THE CAPT ENTERED THE MAINT DISCREPANCY INTO THE LOGBOOK. PER NORMAL PROCS; THE FRM WAS CONSULTED WHEN COMPLETING THE LOGBOOK ENTRY. THE CAPT SHOWED ME THAT ONE OF THE FIRST QUESTIONS THE FRM ASKED REGARDING THE SPD BRAKE DEFERRAL -- WAS THERE SIGNIFICANT AIRPLANE ROLL? THIS FRM QUESTION INTRODUCED US TO THE POSSIBILITY THAT THE ROLL WE EXPERIENCED ON LNDG COULD BE ASSOCIATED WITH SPOILER FLOAT. THIS LEFT A QUESTION IN BOTH OUR MINDS AS TO WHETHER OR NOT THE AILERON TRIM DEFERRAL AND THE AUTO SPD BRAKE ISSUE COULD POSSIBLY BE RELATED. MY CAPT CONSULTED WITH MAINT AND THE RESULTING WRITE-UP DETAILED THE AUTO SPOILER PROB AND ALSO INCLUDED DETAIL OF THE POSSIBILITY OF SPOILER FLOAT. AS LUCK WOULD HAVE IT; OUR OUTBOUND FLT WAS ASSIGNED TO THE SAME ACFT. OUR EXPECTATIONS WERE FOR MAINT TO ADDRESS OUR CONCERN OF SPOILER FLOAT. UPON RECEIVING THE FLT RELEASE WE NOTICED THAT THE ONLY OBVIOUS MAINT ACTION WAS THAT THEY DEFERRED THE AUTO SPD BRAKES. THIS DID NOT ADEQUATELY ADDRESS THE SPOILER FLOAT ISSUE; SO WE THEN BROUGHT THIS TO THE ATTN OF THE CHIEF PLT ON DUTY. DURING A CONFERENCE CALL WITH THE CHIEF PLT AND MAINT; WE LEARNED THAT THE INITIAL TRIM WRITE-UP OCCURRED LATE APRIL AND SPECIFIED THAT 2 UNITS OF AILERON TRIM WERE NEEDED BY THE CREW AND NOTED IN THE WRITE-UP. WE ALSO LEARNED THAT 2 UNITS WAS THE MAX AMOUNT OF TRIM ALLOWED TO DEFER PER THE ASSOCIATED MAINT PROC. WE PROCEEDED TO THE AIRPLANE TO HAVE A FACE-TO-FACE WITH MAINT AND DETERMINE IF THEY TESTED FOR THE POSSIBILITY OF SPOILER FLOAT. THEY HAD NOT; SO WE REQUESTED THAT AN ACP COME TO THE AIRPLANE. THE ACP DID NOT THINK SPOILER FLOAT WAS A CONCERN. ACCORDING TO HIM; IF IT WAS SPOILER FLOAT; WE WOULD HAVE RECEIVED A SPOILER CAUTION MESSAGE. SINCE THE ROLL OCCURRED WHEN FLAPS WERE EXTENDED PAST 20 DEGS (PER PREVIOUS WRITE-UP; I AM NOT SURE WHAT FLAP SETTING INTRODUCED THE ROLL) HE BELIEVED IT COULD BE A PROB WITH THE LEADING EDGE SLATS EXTENDING FOR LNDG. THE ACP SAID TIME DID NOT ALLOW FOR THEM TO CHK THE SPOILERS AND THAT IF WE FLEW IT TO ZZZ THEY WOULD CHK THE SPOILERS THERE. THE CAPT AND I DISCUSSED OUR COMFORT LEVEL WITH THE AIRPLANE. CONSIDERING THE URGING OF THE ACP; THE FACT THAT WE FLEW THE AIRPLANE INBOUND AND KNEW WHAT TO EXPECT UPON LNDG AND THAT WE COULD NOT DEFINITELY PROVE IT WAS A SPOILER FLOAT PROB; WE ACCEPTED THE AIRPLANE. AS A SIDE NOTE; MAINT MADE REPEATED MENTION THAT WE SHOULD HAVE BEEN PROVIDED WITH A PAPER TO DOCUMENT TRIM SETTINGS FOR EACH FLT LEG; HE BELIEVED THIS WAS PART OF THE DEFERRAL. WE EXPLAINED TO HIM THAT WE DID NOT RECEIVE THIS PAPERWORK AND THEN HE SAID IT ISN'T REQUIRED FOR EACH LEG. UPON LNDG (MY LEG); THE CAPT NOTED THE AILERON TRIM REQUIRED WAS BTWN 2 AND 4 UNITS AND FOR THE MOST PART STEADY AT 3 UNITS. THIS INFO WAS THEN ENTERED INTO THE LOGBOOK. AFTER SPEAKING WITH MAINT UPON DEPLANING; WE LEARNED THAT 3 UNIT DISPLACEMENT ALLOWS DEFERRAL FOR A 30 DAY PERIOD AND THEIR INTENTIONS WERE TO TURN THIS AIRPLANE OUTBOUND WITH THAT NEW DEFERRAL. THIS GAVE ME THE IMPRESSION THAT THEY WERE NOT GOING TO CHK FOR SPOILER FLOAT AS PROMISED BY THE CHIEF PLT. MY CAPT THEN CONTACTED THE UNION TO DISCUSS OUR CONCERNS AND LATER BRIEFED ME THAT THE AIRPLANE HAD BEEN REMOVED FROM SVC. IN SUMMARY; I HAVE 3 CONCERNS WITH THE EVENTS THAT OCCURRED: THE AILERON TRIM DEFERRAL PROVIDED US WITH NO SPECIFIC INFO AS TO THE AMOUNT OF TRIM REQUIRED; WE HAD NO WAY OF REFING THE PREVIOUS WRITE-UP. I UNDERSTAND THE MAINT MANUAL WAS WRITTEN BY PEOPLE WITH EXPONENTIALLY MORE B757 KNOWLEDGE THAN MYSELF. HOWEVER; I BELIEVE THAT A SIGNIFICANT REQUIREMENT FOR AILERON TRIM SHOULD NOT BE ALLOWED TO BE DEFERRED. LOW LEVEL ROLL IS NEVER A DESIRABLE TRAIT OF AN AIRPLANE I FLY. WHEN ARMED WITH SPECIFIC KNOWLEDGE OF PAST WRITE-UPS THE NORMAL APCH AND LNDG WAS MANAGEABLE. I WOULD BE CONCERNED THAT IF THIS PROB EXISTED WITH SOME TYPE OF ENG MALFUNCTION; CTL INPUTS REQUIRED WOULD BE THOSE THAT CREWS HAVE NOT BEEN SUBJECTED TO IN SIMULATOR TRAINING (I'VE NEVER HAD A SIMULATOR SESSION WITH ENG OUT PROCS AND AILERON TRIM REQUIREMENTS UPON FLAP EXTENSION). LASTLY; THE FRM REFED THE POSSIBILITY OF SPOILER FLOAT; AND BECAUSE OF THAT; WE ENTERED THAT INFO INTO THE LOGBOOK. WE WERE DISAPPOINTED THAT THE AIRPLANE WAS RETURNED TO SVC WITHOUT AT LEAST VERIFYING THE PROPER OP OF THE SPOILERS.

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.