Source: www.unitedafa.org

The newest 737-900 aircraft, designated at the 73B, began scheduled service today.  Currently, there are a total of six (6) 737-900 aircraft (#3801-3806) that have been pre-scheduled and assigned to specific flight segments for the November schedule month and beyond.   

The addition of the 73B aircraft into the schedule has already begun to generate questions from Flight Attendants.  These aircraft have been incorporated into the schedules of s-UA Flight Attendants in the following way:

• These aircraft have been created as a specific sub-fleet of 737 aircraft and are designated as 73B.  This aircraft type is assigned only at s-UA and does not appear (nor can it be incorporated) in IDs or pairings built at s-CO on either a pre-scheduled or operational basis.
• The 73B equipment will be assigned aircraft numbers in the 38XX series.
• The equipment type for this aircraft will be designated as 73B in our IDs. 
• Initially, these aircraft will be flown by pilots from the s-CO subsidiary.
• These flights will have four (4) digit flight numbers in the range of flight numbers traditionally assigned to s-CO. 
• These aircraft will have a placard in the forward galley that will identify this aircraft for Flight Attendant work groups as the "United" or "73B" aircraft.
• FAA minimum staffing on these aircraft is four (4) Flight Attendants.  All domestic segments will be covered by a pre-scheduled base ID of three (3) Flight Attendants and one (1) XSC position to cover these required positions.  It can't be stressed strongly enough that there are no circumstances under which this aircraft can be dispatched for passenger service with less than four (4) Flight Attendants.
• Refer to the Flight Attendant Operations Manual for additional security information.

While there have been a number of reports of s-UA Flight Attendants being assigned to work s-CO aircraft and vice versa, it is important to understand that automation is in place to prevent such instances.  We strongly recommend that you secure a copy of your ID (and any subsequent reassignment) to ensure that the computer work has been done so that the automation that is in place will ensure only Flight Attendants on the United System Seniority list are assigned to work s-UA aircraft.