Narrative:

While in cruise at FL390; got a 'le edge slat asym' EICAS message and caution beeper; but no discreet leading edge lights. Both flap indicators were symmetrically halfway between up and 1. No vibration or buffeting; aircraft altitude excursion; or noticeable autopilot compensation was noted. We accomplished QRH procedure up to actually extending te flaps via alternate system. QRH noted to observe airspeed limitations; which would be 240 KIAS for flaps 1 (we were indicating partially extended). However; in the aircraft limitations section is a maximum altitude limitation of FL200 for flap extension; which the first officer pointed out shortly after QRH items accomplished. I'd reduced speed from 247 KIAS to 240 KIAS or less. Flap handle was verified to be in the up position. As QRH made no mention of altitude; I accomplished descent near normal top of descent at a rate consistent with idle 240 KIAS. In terminal area; positioning flap handle to 1; then 5 did not produce any flap extension; so accomplished alternate flap extension procedure to flaps 20 as called for. Alternate extension worked normally; no issues landing; post flight inspection revealed inboard leading edge flaps were symmetrically extended 1/3 - ½ extension; no apparent damage. In retrospect; there appears to be a gap in QRH in that it makes no mention of altitude or covers situation I faced. Obviously; would not intentionally extend/operate flaps above FL200; but absence of discrete light (leading edge) made me think indication anomaly. My situation was benign that there were plenty of airports; but would going down to FL200 halfway across ocean be called for?

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Original NASA ASRS Text

Title: B767 Captain experienced a LE Slat Asym EICAS message at FL390 but no discrete LE lights with flap handle in the retracted position. A QRH procedure was attempted before recalling that flaps are not to be extended above FL200. A flap 20 landing ensued at destination using the alternate flap selector.

Narrative: While in cruise at FL390; got a 'LE Edge Slat Asym' EICAS message and caution beeper; but no discreet leading edge lights. Both flap indicators were symmetrically halfway between UP and 1. No vibration or buffeting; aircraft altitude excursion; or noticeable autopilot compensation was noted. We accomplished QRH procedure up to actually extending TE flaps via Alternate System. QRH noted to observe airspeed limitations; which would be 240 KIAS for flaps 1 (we were indicating partially extended). However; in the aircraft limitations section is a maximum altitude limitation of FL200 for flap extension; which the First Officer pointed out shortly after QRH items accomplished. I'd reduced speed from 247 KIAS to 240 KIAS or less. Flap handle was verified to be in the UP position. As QRH made no mention of altitude; I accomplished descent near normal top of descent at a rate consistent with idle 240 KIAS. In terminal area; positioning flap handle to 1; then 5 did not produce any flap extension; so accomplished alternate flap extension procedure to flaps 20 as called for. Alternate extension worked normally; no issues landing; post flight inspection revealed inboard leading edge flaps were symmetrically extended 1/3 - ½ extension; no apparent damage. In retrospect; there appears to be a gap in QRH in that it makes no mention of altitude or covers situation I faced. Obviously; would not intentionally extend/operate flaps above FL200; but absence of discrete light (leading edge) made me think indication anomaly. My situation was benign that there were plenty of airports; but would going down to FL200 halfway across ocean be called for?

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.