Date: 201306
Local time of day: 1201-1800
Location: E10.TRACON, CA
Aircraft: B717 (Formerly MD-95)
Operator: Air Carrier
Operating under: Part 121
Flight plan: IFR
Flight phase: Cruise
ATC / advisory: TRACON E10
Reporter organization: Government
Reporter function: Departure
Human factors: Situational Awareness; Communication Breakdown
Second reporter function: Instructor; Departure
Anomaly: ATC Issue All Types; Airspace Violation All Types; Deviation / Discrepancy - Procedural Published Material / Policy
Contributing factors: Procedure; Human Factors; Aircraft
Primary problem: Human Factors

Narrative: I was assigned the sector after returning from a break. I plugged in to receive the briefing from the Trainee and Trainer working the position. They completed the brief (or so we thought) on the sector and began the task of them unplugging from the sector so I could plug into the sector. They were plugging into the handoff position to complete their two minute overlap. When I looked up at the sector again is when I noticed there was an IFR tag within [a Restricted Area]. It was [Flight XXX] and it showed we owned the tag. So I asked; 'Who's this guy?' As it's common for aircraft to accidentally squawk another aircraft's code; my first thought was that was what was happening. But when the Trainer jumped on the line to [the controlling sector] so quickly I realized that it was an actual IFR aircraft they had released off of XXX (heading 350 climbing to 120) but never heard from. I quickly told the aircraft to turn left heading 220 immediately. The aircraft responded and I was able to get the aircraft back out of [the Restricted Area] quickly and without incident. There were no military participants in the area. Once [the flight] was clear of [the Restricted Area] we were able to get the aircraft on course. Before shipping the aircraft to [Center]; I asked [the flight] if they'd had any problems trying to reach us and the aircraft responded saying that they didn't hear anything for them until I told them to turn left immediately. I then shipped [the flight] to [Center] without further incident. The incident happened so quickly that I hadn't had time to review my strips to see that someone had been released off of XXX but that I wasn't briefed on it. However; when the data tag populated the Trainer and Trainee instantly knew who it was. After reviewing the tapes and the radar data; we were only receiving a primary target until about 1 mile outside the Restricted Area and that was when [the flight's] beacon code popped up and then the data tag popped up on the boundary of [the Restricted Area]. Apparently the pilot had checked on but was mistaken for another aircraft and the instructions given mirrored what [the flight] had been given on release off of XXX. The pilot didn't use his call sign but readback the other aircraft's instructions. The other aircraft verified that was for them and the Trainer and Trainee confirmed it was as they didn't see a data tag off of XXX. The pilot didn't make any further transmissions and never questioned whether he was allowed to enter the Restricted Area or when he could expect on course. I recommend that before receiving a relief briefing that I review all of the strips so if there is a strip on an aircraft but it's not discussed during the brief that I can then ask about the aircraft to ensure I receive a full briefing. I would also recommend that the Trainee and Trainer do the same before giving the briefing so they can make sure they are giving a complete relief briefing. I would recommend that if a pilot is departing off of XXX they need to be aware of the surrounding airspace (Restricted Areas) and question whether or not they should be entering a restricted area. I think that the pilot also should have used his callsign reading back the altimeter and altitude which would have alerted the Trainer and Trainee that their departure had departed but that they weren't receiving a transponder. Also; once the other aircraft confirmed those instructions were for them and the controller's confirmed it was; the pilot should have advised that he was the one that acknowledged those instructions the first time and wanted to confirm what he needed to be doing.


Second narrative: No additional information.


Synopsis: During a break briefing; the relieving Air Traffic Controller as well as the Trainer and Trainee were surprised to observe the tag for an IFR aircraft appear within a Restricted Area. The crew had not adequately established communication and the aircraft's transponder beacon had not been observed sooner for an unknown reason. The aircraft was provided a heading out of the Restricted Area and handed off to another sector.