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An airbus A320 series flight crew reported descending on the clt ivane 5 RNAV they were assigned a 250 kt restriction. While in managed speed; the FMC ignored the mayos altitude constraint and projected missing the kiyen altitude constraint. The aircraft had difficulty flying a modified RNAV optimal profile descent.
| Attributes | |
| ACN | 1346611 |
| Time | |
| Date | 201604 |
| Local Time Of Day | 1201-1800 |
| Place | |
| Locale Reference | CLT.Airport |
| State Reference | NC |
| Environment | |
| Flight Conditions | VMC |
| Light | Daylight |
| Aircraft 1 | |
| Make Model Name | Airbus 318/319/320/321 Undifferentiated |
| Operating Under FAR Part | Part 121 |
| Flight Phase | Descent |
| Route In Use | STAR IVANE 5 |
| Flight Plan | IFR |
| Component | |
| Aircraft Component | FMS/FMC |
| Person 1 | |
| Function | First Officer Pilot Flying |
| Qualification | Flight Crew Air Transport Pilot (ATP) |
| Person 2 | |
| Function | Captain Pilot Not Flying |
| Qualification | Flight Crew Air Transport Pilot (ATP) |
| Events | |
| Anomaly | Aircraft Equipment Problem Less Severe Deviation - Altitude Crossing Restriction Not Met Deviation - Altitude Overshoot Deviation - Procedural Clearance Deviation - Procedural Published Material / Policy Deviation - Speed All Types |
Narrative:
In cruise at FL320 we were assigned a descend via IVANE5; except maintain 250. I input 250kts in the descent page; deleted all speed restrictions above 250kts; cami'd and ensured managed speed was engaged. We had previously verified the entire arrival procedure; including all altitude restrictions and airspeeds. Upon receiving the clearance I selected managed descent; and again verified managed speed was selected. The aircraft began down; with a bracket speed around 250kts. The FMC respected the first altitude restriction of FL270 at mstrd; upon crossing mstrd we noticed that the aircraft was accelerating rapidly in the descent; while initially maintaining over 50% N1. We were discussing this; and observed the power levelers approach idle. We were slightly above (one dot) our descent profile. We then noticed that we had descended below the 240-260 window at mayos. We were approaching FL220 and would have continued a rapid descent below 220 well prior to kiyen. We verified that managed speed; LNAV; and managed descent were all engaged. We were still indicating above profile; and well over our managed speed target. We disabled the automation; and manually captured FL220 to prevent further deviation. The captain informed ATC that we were discontinuing the ivane arrival; and the flight continued normally. We cami'd the IVANE5; as well as the speed changes. We discussed the top of descent; and anticipated a normal approach. We are not sure what caused this FMS anomaly. Ultimately; the concern over the airspeed deviation caused both of us to focus on that; allowing us to miss the further anomalies. The aircraft often has issues when an optimal profile descent (opd) is manipulated outside of the database parameters and requires diligence. This [has] become a 'standard' practice for ATC. Deviations from established opd procedures should be kept to a minimum.
Original NASA ASRS Text
Title: An Airbus A320 series flight crew reported descending on the CLT IVANE 5 RNAV they were assigned a 250 kt restriction. While in managed speed; the FMC ignored the MAYOS altitude constraint and projected missing the KIYEN altitude constraint. The aircraft had difficulty flying a modified RNAV optimal profile descent.
Narrative: In cruise at FL320 we were assigned a descend via IVANE5; except maintain 250. I input 250kts in the descent page; deleted all speed restrictions above 250kts; CAMI'd and ensured managed speed was engaged. We had previously verified the entire arrival procedure; including all altitude restrictions and airspeeds. Upon receiving the clearance I selected managed descent; and again verified managed speed was selected. The aircraft began down; with a bracket speed around 250kts. The FMC respected the first altitude restriction of FL270 at MSTRD; upon crossing MSTRD we noticed that the aircraft was accelerating rapidly in the descent; while initially maintaining over 50% N1. We were discussing this; and observed the power levelers approach idle. We were slightly above (one dot) our descent profile. We then noticed that we had descended below the 240-260 window at MAYOS. We were approaching FL220 and would have continued a rapid descent below 220 well prior to KIYEN. We verified that Managed Speed; LNAV; and Managed Descent were all engaged. We were still indicating above profile; and well over our managed speed target. We disabled the automation; and manually captured FL220 to prevent further deviation. The Captain informed ATC that we were discontinuing the IVANE arrival; and the flight continued normally. We CAMI'd the IVANE5; as well as the speed changes. We discussed the top of descent; and anticipated a normal approach. We are not sure what caused this FMS anomaly. Ultimately; the concern over the airspeed deviation caused both of us to focus on that; allowing us to miss the further anomalies. The aircraft often has issues when an optimal profile descent (OPD) is manipulated outside of the database parameters and requires diligence. This [has] become a 'standard' practice for ATC. Deviations from established OPD procedures should be kept to a minimum.
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.