Flight crew declared emergency due aircraft control problems while on final approach. TRACON Controller issued priority sequencing to the emergency aircraft; but was instructed by Supervisor to change the sequence and make the emergency aircraft follow another aircraft.

Narrative

I was working the Arrival RADAR positions combined. I took a hand off on Aircraft X descending to 5;000 per SOP. I took another hand off descending to 5;000. At the time it appeared that the aircraft were going to be a tie on a 15 mile final; so I decided to make Aircraft Y first by assigning them a 360 heading to get them in front of Aircraft X. While still in an adjacent airspace Aircraft Y stated that they were having flight control issues and needed to 'circle around out here to run the checklist'. I coordinated with the adjacent sector and they said that Aircraft Y was my control. I was about to issue box vectors to Aircraft Y but they then stated that they were having 'rudder fail 1 and 2 messages; we need priority to the airport; and roll the trucks'. Having been an airline pilot myself; I grasped the reality of the situation and cleared them direct to the airport. At the same time I hollered for the Supervisor to come over to my sector so I could alert him to the situation. While I told him what was going on; I issued Aircraft X a 090 heading to fall in behind Aircraft Y. I received the necessary information (souls; fuel; etc) and passed them along to the Supervisor. My plan was to run Aircraft Y into the airport first since they had a possible flight control failure. In my book this ranks right up there along with fire and fuel starvation. Aircraft X would have to hold as the runway would be closed once Aircraft Y landed; but that is a minor inconvenience. I issued Aircraft Y clearance to 3;000 FT and to report the field in sight for the visual approach. At this point the Supervisor told me to make Aircraft X number one for the airport since the runway would be closing and they would be delayed. I asked him if that was what he really wanted me to do; knowing full well that I didn't want to unnecessarily vector an airplane that may or may not have directional control. He stated again to make Aircraft X number one; and I issued instructions as such. I had to issue Aircraft X direct to the airport and maintain maximum forward speed to a 5 mile final. Aircraft Y on the other hand was on a 010 heading direct to the airport; and subsequently I had to give them a left turn heading 320 and reduce speed to 210 KTS; and advised that they were now number two to follow a Dash 8. Making an aircraft with questionable controllability do a 90 degree turn while reducing airspeed made me feel uncomfortable; and apparently the flight crew thought so as well when they then stated 'Are we still receiving priority to the airport'? I stated for the record 'I was told to put another airplane in before you. These are vectors for sequence'. I had to vector the Aircraft Y to a 15 mile final as to allow room behind Aircraft X; who was on an 8 mile final; cleared for the visual approach to the runway best forward speed to a 5 mile final; and talking to the Tower. At that point; I turned Aircraft Y to a 050 heading; and reduced their speed to 170 KTS (another 90 degree turn). Spacing was sufficient behind Aircraft X; and I cleared them for a visual approach to the runway with a speed restriction of 170 KTS to a 5 mile final to account for compression. Aircraft Y landed without incident and taxied to the ramp. Please note that during all the vectoring that no separation was ever lost between the two aircraft. Recommendation; I would like to use this section to discuss what I view as a significant safety hazard that occurred during the aforementioned narrative. As you may be able to discern; as the Radar Controller; I had every intention to make Aircraft Y number 1 for the airport. As a former airline pilot; I know what a major issue a loss of flight controls is; and that ranks very highly on the scale of in-flight emergencies. When I issued Aircraft Y direct to the airport; I did not want them to have to turn a lot because they may not have been able to do so; resulting in loss of control of the aircraft. I was; quite frankly; flabbergasted beyondbelief when the Supervisor told me to make an emergency aircraft number 2 for the airport. Making Aircraft Y do two 90 degree turns with simultaneous speed reductions just to get behind another aircraft is not what a flight crew with a controllability issue needs or wants at any point. If Aircraft Y was allowed to continue as number one; the most they would have needed to do was a shallow 30 degree turn to line up with the runway. Aircraft X would have had to hold for 5 or 10 minutes while the runway inspection was completed; but I was not that busy where I couldn't allow that. If worse came to worse; say; the weather was IFR; and Aircraft X had to divert to another airport; so what - as long as the emergency aircraft gets on the ground safely; that is the important thing. I believe our facility did the crew and passengers on that aircraft a dangerous disservice by making them follow the Dash 8. I believe a serious safety event was created as a result of the Supervisor's direction to make Aircraft Y number two for the airport. I; as well as the flight crew; had no idea if they could make those kinds of turns. As it turned out; they were able; but why would ATC want to put a flight crew in a position to test the limits of questionable control authority? What if they had lost their rudder; and couldn't do what I was told to do by the Supervisor? If that airplane lost control and crashed merely because I was told to make them number two; does that meet the .65 requirement of providing maximum assistance to an aircraft in distress? I spoke with the Supervisor the next day (today) as I am very distressed and concerned about the decision to vector Aircraft Y around. He more or less told me that was the decision he had made; and that was that. Be that as it may; it displayed to me an utter disregard for the safety of flight of Aircraft Y. I am not trying to get the Supervisor in trouble; I am merely ensuring my concerns about safety of flight are heard by the appropriate parties in case this happens in the future.