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ZLA center controller reported an A320descended into military restricted airspace due to a software flaw in the aircraft FMS.
| Attributes | |
| ACN | 1526257 |
| Time | |
| Date | 201803 |
| Local Time Of Day | 0001-0600 |
| Place | |
| Locale Reference | ZLA.ARTCC |
| State Reference | CA |
| Environment | |
| Light | Night |
| Aircraft 1 | |
| Make Model Name | A320 |
| Operating Under FAR Part | Part 121 |
| Flight Phase | Descent |
| Flight Plan | IFR |
| Person 1 | |
| Function | Enroute |
| Qualification | Air Traffic Control Fully Certified |
| Events | |
| Anomaly | ATC Issue All Types Airspace Violation All Types Deviation - Altitude Excursion From Assigned Altitude Deviation - Procedural Clearance Deviation - Procedural Published Material / Policy |
Narrative:
[Aircraft] checked in on the [RNAV] arrival over [a restricted area] at FL240 with clearance to descend via. [The restricted area] is active surface to 23;000 feet. The first restriction was a number of miles ahead with an altitude window FL300-FL240. [Aircraft] is at the bottom of the restriction. He should not begin his descent until after the fix ahead. I noticed the altitude change to FL238. I verified he was level at FL240. He answered in the affirmative and I then watched him descend to FL237. I told him to stop his descent; climb and maintain FL240 and issued the brasher statement. The pilot complied.airbus aircraft have had this problem since day 1 of the descend via program. If the aircraft is at the bottom of the altitude window and the aircraft presses descend via in the FMS; the FMS will delete the [first] restriction and begin the descent. I have seen this on multiple occasions; not once or twice. At least five times if not more. Airbus and the airlines need to fix this issue. The aircraft descended into restricted airspace where there are fighter jets and other military aircraft that we can't see and are not in communication with [us]. This is a very dangerous problem.
Original NASA ASRS Text
Title: ZLA Center Controller reported an A320descended into military restricted airspace due to a software flaw in the aircraft FMS.
Narrative: [Aircraft] checked in on the [RNAV] Arrival over [a Restricted Area] at FL240 with clearance to descend via. [The Restricted Area] is active surface to 23;000 feet. The first restriction was a number of miles ahead with an altitude window FL300-FL240. [Aircraft] is at the bottom of the restriction. He should not begin his descent until after the fix ahead. I noticed the altitude change to FL238. I verified he was level at FL240. He answered in the affirmative and I then watched him descend to FL237. I told him to stop his descent; climb and maintain FL240 and issued the brasher statement. The pilot complied.Airbus aircraft have had this problem since day 1 of the descend via program. If the aircraft is at the bottom of the altitude window and the aircraft presses descend via in the FMS; the FMS will delete the [first] restriction and begin the descent. I have seen this on multiple occasions; not once or twice. At least five times if not more. Airbus and the airlines need to fix this issue. The aircraft descended into restricted airspace where there are fighter jets and other military aircraft that we can't see and are not in communication with [us]. This is a very dangerous problem.
Data retrieved from NASA's ASRS site and automatically converted to unabbreviated mixed upper/lowercase text. This report is for informational purposes with no guarantee of accuracy. See NASA's ASRS site for official report.