Narrative:

This is more a safety problem than a safety event; but an event also occurred because of the safety problem.aircraft X was in level flight at FL240; and was issued a clearance to descend via the HLYWD1 arrival. The aircraft was well before the bruen altitude window at 240b300; but the pilot reported leaving FL240. The controller immediately caught the read back; told the pilot to maintain FL240; and I was told that mode-C did not indicate the aircraft leaving FL240.the aircraft was issued the brasher warning by me on the next sector's frequency (I was working the low altitude sector at the time of the incident); and upon landing at lax; the pilot and co-pilot called me as requested. The pilots didn't really have much useful information to add.as a general trend; we have noticed that this same situation has been happening very regularly with [airline name removed]. While this incident did not result in the aircraft busting its assigned altitude; the majority of these situations do result in altitude deviations. Being dissatisfied with the answers I was receiving from the pilots; I contacted the [airline] chief pilot on duty for the area. I had a very good and long conversation regarding what took place and why. The [chief pilot] explained that in airbus aircraft; when the aircraft is in level flight (cruise phase according to a [specific aircraft type] systems; at FL240; for example; the altitude constraint of 240b300 would be deleted from the onboard computer; unless the aircraft climbed to a higher cruise altitude; i.e. FL280 or 300). It is up to the pilots to verify the altitude restrictions manually per the physical/electronic charts. The pfd and mcdu delete the upcoming altitude restraint; and any subsequent altitude restraints unless the window is lower than the present cruise altitude of the aircraft. [Airline] company policy dictates that each pilot must independently verify the altitude windows prior to descending the aircraft. That obviously did not happen in this event; and was definitely pilot error; however; what a completely stupid and useless system that deletes the altitude constraints in this fashion. [Chief pilot] noted that the same thing would happen; for example; even on longer routes; where a pilot departing ZZZ might choose a lower altitude because of reported turbulence; etc. They might fly across the entire country at a lower altitude; and accordingly; the upcoming constraints (potentially all the way across the country in ZLA airspace) would be deleted. How can it be acceptable for an aircraft to simply delete applicable altitude constraints on an arrival? Human error is going to take place. We all know that. The two pilots on aircraft X both independently missed the altitude constraints; and to be perfectly honest; it's a very easy thing to miss when you are in the descent phase of flight and have a lot of things going on in the cockpit. This time; there was no loss of separation (or life); but this should absolutely be corrected; as the potential for error and loss of separation is extremely high.fix the airbus computers so what they are doing makes sense. It's completely idiotic for the computer to delete pertinent altitude restrictions; even more so for an aircraft that loves flying itself with minimal/no pilot intervention.

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Original NASA ASRS Text

Title: Two ZLA Controllers reported an aircraft did not make the crossing restrictions after being cleared to descend via because of an ongoing aircraft type computer problem.

Narrative: This is more a safety problem than a safety event; but an event also occurred because of the safety problem.Aircraft X was in level flight at FL240; and was issued a clearance to descend via the HLYWD1 arrival. The aircraft was well before the BRUEN altitude window at 240B300; but the pilot reported leaving FL240. The controller immediately caught the read back; told the pilot to maintain FL240; and I was told that Mode-C did not indicate the aircraft leaving FL240.The aircraft was issued the Brasher Warning by me on the next sector's frequency (I was working the low altitude sector at the time of the incident); and upon landing at LAX; the pilot and co-pilot called me as requested. The pilots didn't really have much useful information to add.As a general trend; we have noticed that this same situation has been happening very regularly with [Airline name removed]. While this incident did not result in the aircraft busting its assigned altitude; the majority of these situations do result in altitude deviations. Being dissatisfied with the answers I was receiving from the pilots; I contacted the [Airline] Chief Pilot on Duty for the area. I had a very good and long conversation regarding what took place and why. The [Chief Pilot] explained that in Airbus aircraft; when the aircraft is in level flight (Cruise Phase according to a [specific aircraft type] systems; at FL240; for example; the altitude constraint of 240B300 would be deleted from the onboard computer; unless the aircraft climbed to a higher cruise altitude; i.e. FL280 or 300). It is up to the pilots to verify the altitude restrictions manually per the physical/electronic charts. The PFD and MCDU delete the upcoming altitude restraint; and any subsequent altitude restraints unless the window is lower than the present cruise altitude of the aircraft. [Airline] Company Policy dictates that each pilot must independently verify the altitude windows prior to descending the aircraft. That obviously did not happen in this event; and was definitely pilot error; however; what a completely stupid and useless system that deletes the altitude constraints in this fashion. [Chief Pilot] noted that the same thing would happen; for example; even on longer routes; where a pilot departing ZZZ might choose a lower altitude because of reported turbulence; etc. They might fly across the entire country at a lower altitude; and accordingly; the upcoming constraints (potentially all the way across the country in ZLA airspace) would be deleted. How can it be acceptable for an aircraft to simply delete applicable altitude constraints on an arrival? Human error is going to take place. We all know that. The two pilots on Aircraft X both independently missed the altitude constraints; and to be perfectly honest; it's a very easy thing to miss when you are in the descent phase of flight and have a lot of things going on in the cockpit. This time; there was no loss of separation (or life); but this should absolutely be corrected; as the potential for error and loss of separation is extremely high.Fix the Airbus computers so what they are doing makes sense. It's completely idiotic for the computer to delete pertinent altitude restrictions; even more so for an aircraft that loves flying itself with minimal/no pilot intervention.

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.