EMB ERJ 170/175 ER/LR
Air Traffic Control Fully Certified
Air Traffic Control Time Certified In Pos 1 (yrs) 11.0
Situational Awareness; Troubleshooting
ATC Issue All Types; Aircraft Equipment Problem Less Severe; Airspace Violation All Types; Deviation - Track / Heading All Types; Deviation / Discrepancy - Procedural Clearance; Deviation / Discrepancy - Procedural Published Material / Policy
Air Traffic Control Issued Advisory / Alert; Air Traffic Control Issued New Clearance; Flight Crew Became Reoriented; Flight Crew FLC Overrode Automation; Flight Crew Requested ATC Assistance / Clarification; Flight Crew Overcame Equipment Problem
Chart Or Publication; Airspace Structure; Aircraft; Human Factors
Restricted area was active 28;000 feet and below. Aircraft X was in Sector 37 and he had not checked on yet. As I saw his altitude descending; since he hadn't checked on yet; I asked Sector 37 why aircraft was descending; and did he still have aircraft? Sector 37 had already shipped him; so I checked to see if he was on my frequency; and told aircraft to climb and maintain 29;000 feet for restricted airspace. He responded; and then I asked him what his previous clearance was. He stated it was 'to cross SALYY at FL290; then descend via the ANJLL 1 arrival.' He stated his FMS did not work properly. This seems to be an ongoing FMS issue with pilots on the descent via on the ANJll1. They are not following our instructions to keep them clear of military airspace because of their FMS issue. They even have trouble checking on with the verbiage to cross SALYY at FL290 then descend via. This is very dangerous and it is a problem that needs to be fixed.I would recommend for this restriction to cross SALYY at or above FL290 be on the STAR and have Sector 37 have them maintain the top of the restricted airspace which today would be FL290. Then once they pass restricted airspace; give the aircraft the 'descend via'. It is better for the pilots and the controllers to not have to repeat the SALYY restriction to them a million times because it is time consuming. You can get extremely busy with all the repetition; and is obviously a pilot FMS issue as well. It needs to be fixed ASAP before another incident occurs. It happened yesterday as well with another controller and pilot.
Upon descent on the STAR we were given the clearance to descend via except cross a fix at 29;000 feet. I was the pilot flying and entered FL290 as a hard altitude for the fix into the FMS and 12;000 feet into the altitude alerter and activated VNAV. My First Officer and I had already verified all the speed and altitude restrictions on the arrival as part of the briefing before the arrival. As the aircraft descended via VNAV the First Officer and I noticed we were descending below FL290 before the fix crossing restriction. I immediately switched to Flight Path Angle (FPA) mode and climbed back to the restricted altitude as ATC inquired about our clearance.The deviation was approximately 1;000 feet. As we were trying to figure out what happened we noticed that the FMS had deleted all speeds and altitude restrictions on the entire arrival. After we leveled out the First Officer helped read out the speed and altitudes on the arrival and I reentered them manually in the FMS and reselected VNAV. A few minutes later we noticed the FMS again deleted the speeds and altitudes on the arrival. This time however we were able to catch it before any further deviations occurred.From this point on I flew the arrival in manual speeds and green FPA modes entirely manual as I no longer had any trust in the FMS. At this point I was task saturated trying to make the many speed and altitude restrictions as my First Officer worked on again trying to reload the arrival. At the approach phase the FMS seemed to work so I went back to the automation for the ILS Approach. Upon arrival I wrote up the anomaly.I have no idea how or why it kept deleting speed and altitude restrictions. Contributing factors included high work load environment exactly at the same time as the deviation. I have learned to not rely on VNAV and how important it is to verify the VNAV is actually doing what you have programed.
A center controller and flight crew reported an aircraft did not comply with a crossing restriction and descended into restricted airspace.