Narrative:

I was the pilot flying and we were being vectored for a visual approach for runway xyc. There were gusty winds (20g30) with wind shear advisories in effect. I began configuring the airplane at 3000 ft with localizer intercept. At flaps 15 degrees; both the captain and I saw intermittent flashes of the master caution light but were not sure of the cause. Flaps were lowered to 22/ext and we received a steady master caution light with a resultant slat disag yellow box. There was no concurrent airplane controllability issues with the slat disag light. We requested a go around. Tower gave us a vector to 180 degrees and a climb to 4000 ft. I was still pilot flying as the captain assessed the situation; and pulled out the QRH. We followed the checklist as well as re-configured a second time to assess if this was a onetime event or if the slat disag light would return. It repeated the exact same sequence that it did when I was configuring on final to runway xyc. Flaps 15; intermittent master caution light; followed by flaps 22/ext steady caution light and slat disag light. The checklist was a little confusing as it was driving us to a flaps 22/ext landing which didn't make sense to us since the slat disag illuminated at flaps 22; so the captain asked that I back her up by reading the checklist and confirming that was in fact what the checklist said. I transferred control of the airplane to her and also came to the same conclusion that she did. We had a check airman on board and he also backed us up on the checklist. We all agreed that a flaps 22/ret landing was the checklist that needed to be done instead since the slat disag light illuminated steady at flaps 22; so we complied with the QRH and did those procedures. We [advised] ATC; asked for runway xyr as it is the longest runway; used the tables to determine vref/vapp. We were at 320000 pounds landing weight and the takeoff and landing performance assessment (talpa) codes for runway xyr were 5/5/5 (wet). We determined our landing rollout distance to be approximately 9500 or so. Vref was 188. Vapp 192. We discussed the sight picture of a flaps 22 landing and the increased rate of descent that would be normal for that type of landing. We discussed a go around in the event of wind shear and a go around in the event of an unstable approach (two different procedures). The captain brought the jump seater up to the cockpit who was an off duty mechanic to see if he had anything to add. The line check airman was also integral to our discussions and checklist application and was a huge asset to our cockpit teamwork. Landing was uneventful. We taxied clear of runway xyr then hold short of runway xyc. We were then cleared across xyc to the ramp. The fire trucks followed us to the gate. Sensor failure of the slats.not really sure that this is an applicable section. Stuff breaks; wears out and gets dirty. That is life. However; the slat disag checklist should be cleaned up just a little; to perhaps include a potential sensor failure option.

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Original NASA ASRS Text

Title: MD11 flight crew reported a slat disagree indication; they followed the QRH and landed with a reduced flap configuration and high approach speed. Post flight analysis showed it was a sensor problem which the QRH did not address.

Narrative: I was the pilot flying and we were being vectored for a visual approach for Runway XYC. There were gusty winds (20G30) with wind shear advisories in effect. I began configuring the airplane at 3000 ft with localizer intercept. At flaps 15 degrees; both the Captain and I saw intermittent flashes of the master caution light but were not sure of the cause. Flaps were lowered to 22/EXT and we received a steady master caution light with a resultant SLAT DISAG yellow box. There was no concurrent airplane controllability issues with the SLAT DISAG light. We requested a go around. Tower gave us a vector to 180 degrees and a climb to 4000 ft. I was still pilot flying as the Captain assessed the situation; and pulled out the QRH. We followed the checklist as well as re-configured a second time to assess if this was a onetime event or if the SLAT DISAG light would return. It repeated the exact same sequence that it did when I was configuring on final to RWY XYC. Flaps 15; intermittent master caution light; followed by Flaps 22/EXT steady caution light and SLAT DISAG light. The checklist was a little confusing as it was driving us to a Flaps 22/EXT landing which didn't make sense to us since the SLAT DISAG illuminated at flaps 22; so the captain asked that I back her up by reading the checklist and confirming that was in fact what the checklist said. I transferred control of the airplane to her and also came to the same conclusion that she did. We had a check airman on board and he also backed us up on the checklist. We all agreed that a flaps 22/RET landing was the checklist that needed to be done instead since the SLAT DISAG light illuminated steady at flaps 22; so we complied with the QRH and did those procedures. We [advised] ATC; asked for RWY XYR as it is the longest runway; used the tables to determine Vref/Vapp. We were at 320000 LBS landing weight and the Takeoff and Landing Performance Assessment (TALPA) codes for RWY XYR were 5/5/5 (WET). We determined our landing rollout distance to be approximately 9500 or so. Vref was 188. Vapp 192. We discussed the sight picture of a flaps 22 landing and the increased rate of descent that would be normal for that type of landing. We discussed a go around in the event of wind shear and a go around in the event of an unstable approach (two different procedures). The captain brought the jump seater up to the cockpit who was an off duty mechanic to see if he had anything to add. The Line Check Airman was also integral to our discussions and checklist application and was a huge asset to our cockpit teamwork. Landing was uneventful. We taxied clear of RWY XYR then hold short of RWY XYC. We were then cleared across XYC to the ramp. The fire trucks followed us to the gate. Sensor failure of the SLATS.Not really sure that this is an applicable section. Stuff breaks; wears out and gets dirty. That is life. However; the SLAT DISAG checklist should be cleaned up just a little; to perhaps include a potential sensor failure option.

Data retrieved from NASA's ASRS site 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.