A320
Flight Crew Air Transport Pilot (ATP)
Human-Machine Interface; Situational Awareness
Deviation - Altitude Crossing Restriction Not Met; Deviation - Altitude Overshoot; Deviation / Discrepancy - Procedural Clearance
Air Traffic Control Issued New Clearance; Flight Crew Became Reoriented
Aircraft; Human Factors
[We were] cruising at FL240 given the EAGLE5 Runway 25L transition. Set final altitude of 4000 MSL in altitude selector and verified by First Officer. At indicated top-of-descent point selected managed descent on autopilot and managed the speed. All crossing restrictions had been verified prior to descent. At PAYSO Intersection I noticed that we were at FL230 at 270 KIAS instead of the published FL240-FL280. Apparently the crossing restriction in the FMC had been deleted by our new cruise altitude (FL240). I had checked the crossing restrictions on the arrival prior to descending to FL240. When we descended to FL240; that altitude was added as a cruise altitude. I did not notice the restriction at PAYSO Intersection had been deleted (apparently automatically). I will be checking each crossing restriction as it comes up on the descent in addition to the normal pre-descent check of all restrictions.
Level at FL240 received clearance to descend via EAGUL 5 to 25L. Captain set 4;500 FT in FCU alt window but then pushed it. The airplane was still in cruise phase and this reset cruise alt to 24;000 thereby deleting the 24;000 minimum altitudes at PAYSO and the airplane started down. I had checked all alts in box prior to this but we did not catch the newly deleted restriction until about FL230. I then noticed problem and the Captain told Center and we were cleared to our present altitude. This has been a problem with the FMGC for years and has not been fixed.
A320 flight crew reports inadvertently deleting a crossing restriction on the EAGLE5 RNAV arrival to PHX; resulting in an early descent below the fix altitude.