Regional Jet 200 ER/LR (CRJ200)
Air Traffic Control Fully Certified
Confusion; Communication Breakdown
ATC Issue All Types; Deviation / Discrepancy - Procedural Clearance; Deviation / Discrepancy - Procedural Published Material / Policy
General None Reported / Taken
Human Factors; Company Policy
Flight ABCD and Flight ABGD taxied out for departure within minutes of each other at SLC. I believe one was a CRJ900 and one was a CRJ200. I am reasonably sure that I used the right call sign but the flight strips were right next to each other in the bay and I apparently grabbed the wrong one. The aircraft got down to the end and the Local Controller departed the aircraft and it wasn't until after the aircraft tagged up that he/she realized that he/she had the wrong strip. It wasn't a dangerous situation this time; however it could have been because we routinely use visual separation between aircraft. It could have been a same route situation and we could have been expecting different routes and been applying visual. The similar sounding call signs and the darkness were the main culprits. I believe I would have caught the problem had it been daytime because I would have noticed the difference. Later on in the session there was another situation between Flight ACBD and Flight ADBC on the same departures respectively. We handled those without incident but it's another example of the problem we have with airline call signs. I also may have caught the first situation had I been a little less busy; the departure push was just starting; so when the original aircraft taxied; I wasn't busy; but I got busy just after that.
SLC Controller described an unsafe condition when two same company aircraft with similar sounding four digit flight numbers were confused with regard to routing's issued.