Date: 201810
Local time of day: 1201-1800
Location: ZLA.ARTCC, CA
Aircraft: Fighter
Operator: Military
Operating under: Part 91
Flight plan: IFR
Mission: Training
Flight phase: Cruise
Airspace: Class A ZLA; Class E ZLA
ATC / advisory: Center ZLA
Reporter organization: Government
Reporter function: Enroute; Supervisor / CIC
Reporter qualification: Air Traffic Control Fully Certified
Human factors: Time Pressure; Situational Awareness; Confusion; Communication Breakdown; Workload
Anomaly: Aircraft Equipment Problem Critical; Airspace Violation All Types; Deviation - Altitude Excursion From Assigned Altitude; Deviation - Track / Heading All Types; Deviation / Discrepancy - Procedural Clearance
Detector: Person Air Traffic Control
When detected: In-flight
Result: Air Traffic Control Issued Advisory / Alert; Air Traffic Control Provided Assistance; Flight Crew Landed in Emergency Condition; Flight Crew Requested ATC Assistance / Clarification; Flight Crew Returned To Departure Airport
Contributing factors: Aircraft; Human Factors
Primary problem: Human Factors

Narrative: The situation was very confusing and complex; and I am still unclear to what all happened. The Aircraft involved were a flight of [military] jet fighters and one of the aircraft had an emergency and wanted to return to base. The controllers initiated flight break up procedures with the flight lead; and issued the new beacon code to the distressed aircraft. I observed this action; but never saw any aircraft squawk the new code. The controller repeatedly tried to get aircraft to squawk the new code; both over the air and through the Flight leader. The last known intention of the distressed aircraft was they needed to descend immediately to below 10;000 feet or so. I then walked over to the low sector controller and I observed that he was also trying to get the [military aircraft] to answer up and squawk the new code. No Answer. Simultaniously; another aircraft in the flight wanted to return to base as well (non emergency) and that aircraft took the original squawk. The second aircraft was identified (believed to be the emergency) and was worked back to base. It turns out; that the actual emergency aircraft 'dumped' it down all the way from 27;000 feet through Low altitude sectors airspace and even through a TRACON's airspace and leveled at 8;000 feet and penetrated through destination airport approach airspace. I reported the confusing situation to my Operations Manager at the front desk. I contacted the TRACON Manager and asked if they worked or observed the distressed [military aircraft] and if there were any separation violations. They said no. I called the base TRACON Supervisor and asked if they heard from the [military aircraft]. They said they were in contact with the aircraft and that his landing safely will be assured with no other issues. The aircraft broke formation; did not come up on frequency; or take assigned squawk; descended through class A airspace from FL270 to 8000 feet. As stated; very quick; and confusing. No separation issues except for airspace.




Synopsis: ZLA Center Supervisor reported a distressed military aircraft broke formation and descended through other facilities airspace returning to the departure airport without clearance or communication with the Center.