Date: 201404
Local time of day: 1801-2400
Location: PHX.Airport, AZ
Light: Daylight
Aircraft: Widebody; Low Wing; 2 Turbojet Eng
Operator: Air Carrier
Operating under: Part 121
Flight plan: IFR
Mission: Passenger
Flight phase: Taxi
Airspace: Class B PHX
ATC / advisory: Tower PHX
Reporter organization: Government
Reporter function: Ground
Reporter qualification: Air Traffic Control Fully Certified
Human factors: Communication Breakdown; Confusion
Anomaly: ATC Issue All Types; Conflict Ground Conflict; Less Severe; Deviation / Discrepancy - Procedural Published Material / Policy; Ground Incursion Taxiway
Detector: Person Air Traffic Control
When detected: Taxi
Contributing factors: Airport; Procedure; Company Policy
Primary problem: Procedure

Narrative: Over the past few months; we have had several memorandums issued regarding the use of Taxiway Romeo with respect to the adjacent ramp Taxi-lane Quebec and aircraft therein. The most recent was issued on [Specified date]. This memo requires us in the Tower to coordinate with Ramp Tower prior to using our Taxiway Romeo due to the amount of different painted lead-in lines as well as aircraft parking on Taxi-lane Quebec. Specifically the last paragraph mentions; 'Additionally Taxiway Romeo; north of transfer point green; must not be used by aircraft larger than a [Large Transport] with winglets; unless coordination is completed with Ramp Tower to suspend operations on alternate blue Q.' As Aircraft X without winglets taxied down Romeo; my FLM came over and asked if I had coordinated with the Ramp Tower; in which I had not. I was then informed that the most recent change now requires us to coordinate with the Ramp Tower prior to an aircraft bigger than a [Large Transport] uses Romeo. After reviewing the past and most current memos; my FLM and I both agreed that Aircraft X did not have winglets; and therefore I may or may not have violated the new Memorandum per its wording and subjectivity. We also agreed that there have been many back and forth changes to who and how each (FAA Tower and Ramp Tower) has to be notified prior to Romeo being used and the chance for confusion because of that is great. In the past; the Ramp Tower was to notify us if a [Large Transport] was pushed onto Quebec so as to prevent Romeo from being used by any aircraft adjacent to it. Now it appears we can't use our own taxiway without asking permission from the Ramp Tower for anything bigger than a [Large Transport] 'with winglets.' Furthermore; I don't recall there being a difference in aircraft group numbers between an aircraft of the same type with or without winglets. The wording in the memo can be construed in a way that causes confusion as it can be taken that an aircraft that doesn't have winglets isn't part of the criteria. It is not safe or a good practice to have the use of our taxiways be dependent upon coordination with a user. In this instance; the movement of one Airline is dependent upon the permission of a competing airline; this being the Ramp Tower; who can; according to the structure of the current memo; arbitrarily delay a flight for reasons unknown to the Tower. We cannot see the official 'green' spot or Taxiway Quebec from our Tower Cab to verify if there is an aircraft that prevents or creates a restriction on Romeo. The number of changes of procedures; governed by memorandums; has been; to say the least; extremely numerous in regards to the restriction on Taxiway Romeo and Taxi-lane Quebec. Each new change has a new procedure and way of governing temporarily how aircraft move on the surface. As outlined in the description of the event; our current memo restricts the movement of aircraft by a specific user's 'yes' or 'no' and not by the actual traffic. It should be our determination in the Tower Cab on rather or not if we can use a taxiway and its restrictions. The current memo needs to be replaced permanently with an LOA that can't be changed on a frequent basis. Until that occurs; the existing LOA needs to be changed with one that requires the Ramp Tower to simply advise the Tower if there is a trigger present to cause a restriction on Romeo so that we in the Tower can move aircraft accordingly; versus asking the Ramp Tower on the fly if a specific aircraft can use a taxiway. I would also recommend that the Tower be equipped with a TV monitor of Taxi-lane Quebec so that we can see Taxi-lane Quebec for ourselves to assist in the movement of traffic. There is already such a system in existence that is used by the Ramp Tower for all of their gates and taxi-lanes.




Synopsis: PHX Ground Controller reports of unclear LOA between Ramp Tower and Control Tower on use of a specific taxiway.