The checklist will incorporate this according to the line no of the airframe and the SB status, that is why it appears in your revision and not all revisions, having said that, it is in Revision 17 onwards.
The symbol <> is still a mystery! This was the original question.
Just for info about the SB:
TAB LIMIT CYCLE OSCILLATION
The following procedures are applicable to all Model 737-
600/700/700C/800 airplanes prior to the incorporation of Boeing
Service Bulletin 737-55A1080, or the production equivalent,
incorporating stiffened elevator tabs.
An elevator tab Limit Cycle Oscillation (LCO) will be characterized
by a high frequency, possible severe vibration, originating in the
tail of the airplane, and emanating forward through the airframe
structure. LCO events have previously occurred at airspeeds greater
than 275 KIAS, and in an altitude range between 10,000 and 25,000
feet following ground deicing/anti-icing of the horizontal
stabilizer. This vibration may, or may not, be felt in the control
column. Cabin crew may be able to confirm the source of any
airframe vibrations. If LCO is suspected in flight, immediately
reduce airspeed (WITHOUT use of speed brakes, or changing aircraft
configuration) to 270 KIAS, or until the vibration ceases, whichever
indicated airspeed is lower.
DO NOT USE SPEED BRAKES FOR THE REMAINDER OF THE FLIGHT
Use of the speed brakes in other emergencies is at the discretion of
the flight crew. Remain at or below the indicated airspeed at which
the vibration ceased for the remainder of the flight, but do not
exceed 270 KIAS. Evaluate the need to land at the nearest
practicable airport. Landing airport selection should be based upon
consideration of all pertinent factors such as: weather, distance to
destination, range available at the reduced airspeed, maximum
landing weight, and possible airframe damage. Use of ground
spoilers during landing rollout is permitted.
Last edited by Avenger; 17th Feb 2011 at 06:48.