Narrative:

Cleared to take off [las 25R] while the non-heavy aircraft in front of us had yet to rotate. Captain was non flying pilot while the first officer was the pilot flying. At 400 feet above the ground; the aircraft encountered the wake turbulence from the preceding 737 and rolled rapidly to the right. I observed the first officer make corrective attempts with the flight controls; while the aircraft continued to roll right. When aircraft control was regained; we were about 10 degrees right of runway centerline. A slight left turn was initiated to return to the departure path; when it was noticed that both FMS units had gone into 'map fail'. ATC was notified that we had lost our ability to navigate and a heading was requested while we attempted to reconfigure the FMS. The FMS came back on line shortly thereafter and we continued to our destination without further issue. The event occurred because of the [las] airport departure procedure for runway 25R. As the preceding airplane is rolling; las tower asks if we have the traffic rolling in sight; and when we say we do; they clear us for take off. While the FAA has outlined wake turbulence separation between different weight classes or aircraft type; it is clear that aircraft of similar type can cause serious wake turbulence problems to one another. Turn on a radio; listen and watch; as airplanes are launched off of 25R. You'll hear airplanes that have just lifted off complain about encountering wake turbulence very low to the ground; and you'll see airplanes rolling sharply in one direction or the other. This is a very dangerous situation that needs to be addressed. While I understand the need to get departures out quickly; this is an accident waiting to happen.

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Original NASA ASRS Text

Title: An air carrier Captain reported encountering wake vortex from a preceding LAS departure when he was cleared for takeoff before the other aircraft was airborne. The reporter criticized the Tower procedure.

Narrative: Cleared to take off [LAS 25R] while the non-heavy aircraft in front of us had yet to rotate. Captain was Non Flying Pilot while the First Officer was the Pilot Flying. At 400 feet above the ground; the aircraft encountered the wake turbulence from the preceding 737 and rolled rapidly to the right. I observed the First Officer make corrective attempts with the flight controls; while the aircraft continued to roll right. When aircraft control was regained; we were about 10 degrees right of runway centerline. A slight left turn was initiated to return to the departure path; when it was noticed that both FMS units had gone into 'MAP FAIL'. ATC was notified that we had lost our ability to navigate and a heading was requested while we attempted to reconfigure the FMS. The FMS came back on line shortly thereafter and we continued to our destination without further issue. The event occurred because of the [LAS] airport departure procedure for runway 25R. As the preceding airplane is rolling; LAS Tower asks if we have the traffic rolling in sight; and when we say we do; they clear us for take off. While the FAA has outlined wake turbulence separation between different weight classes or aircraft type; it is clear that aircraft of similar type can cause serious wake turbulence problems to one another. Turn on a radio; listen and watch; as airplanes are launched off of 25R. You'll hear airplanes that have just lifted off complain about encountering wake turbulence very low to the ground; and you'll see airplanes rolling sharply in one direction or the other. This is a very dangerous situation that needs to be addressed. While I understand the need to get departures out quickly; this is an accident waiting to happen.

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.