Light Transport
Flight Crew Multiengine; Flight Crew Instrument; Flight Crew Flight Instructor; Flight Crew Air Transport Pilot (ATP)
Flight Crew Last 90 Days 60; Flight Crew Total 2800; Flight Crew Type 440
Situational Awareness; Communication Breakdown; Confusion; Human-Machine Interface
ATC Issue All Types; Deviation - Altitude Crossing Restriction Not Met; Deviation - Altitude Undershoot; Deviation - Track / Heading All Types; Deviation / Discrepancy - Procedural Clearance; Deviation / Discrepancy - Procedural Published Material / Policy
Flight Crew Became Reoriented
Chart Or Publication; Human Factors; Procedure
We were proceeding direct to HEVVN when ATC instructed us to cross LEGGT at FL270.  The RNAV arrival had already been loaded in the FMS and briefed with the altitude crossing restrictions confirmed in the flight plan.  FL270 was set and confirmed in the Altitude Preselect and the VNAV was armed.  The airplane intercepted the VPATH and we were given a frequency change.  When the Pilot Monitoring (PM) checked in with the controller advising we were FL28.5 descending to cross LEGGT at FL270; the controller responded that we were past LEGGT and to confirm our crossing restriction.  The PM advised ATC we had an issue/conflict with our FMS and ATC cleared us to expedite a descent to FL190.  The rest of the flight was completed without further event.Reflecting back on the event; I think there are several factors that contributed.  First; the MAATY1 RNAV Arrival is one of the new arrivals as part of the greater Florida Metroplex airspace revamp.  However; the first two fixes in our flight plan on the arrival; HEVVN and LEGGT; are the same first two fixes on the FOOXX5 arrival.  Up until the last month; we had routinely flown the FOOXX5 arrival into TPA numerous times each month for the last several years.  From my perspective; one of the key important differences between the FOOXX5 and MAATY1 arrivals is that all the altitudes listed in the FOOXX5 are 'expect'; while in the MAATY1 they are published as mandatory (without 'expect').  Another key difference is that in the FOOXX5; the procedure calls for a crossing restriction 'AT' LEGGT at FL270...The new MAATY1 procedure calls for a crossing restriction 'AT OR ABOVE' LEGGT at FL270.  When previously loading the FOOXX5 arrival into our FMS; we had to manually enter the crossing altitudes into the flight plan since all of the altitudes in the procedure were 'expect'.  When loading the MAATY1 arrival into our FMS; all of the altitude restrictions are automatically loaded into the flight plan.  So; today when we loaded the MAATY1 into the FMS; both the PM and myself saw the 'at or above FL270' at LEGGT that was automatically loaded in the flight plan when the procedure was selected.  We both mistook that as crossing 'AT FL270'.  Hence; when our VNAV VPATH was intercepted; it had us crossing LEGGT 'at or above FL270' as properly depicted in the published procedure - despite our ATC clearance to cross LEGGT 'AT' FL270.In short summary the factors contributing to this event were:1) New MAATY1 RNAV ARRIVAL in use with common fixes from FOOXX5.2) Same altitude with difference constraints between MAATY1/FOOXX5 ('Expect' FL270 'AT' LEGGT in FOOXX5 vs. published 'AT OR ABOVE' FL270 at LEGGT in MAATY1).3) FMS programming error in FMS VNAV/lack of close cross-checking altitude constraints vs. ATC clearance by crew.4) ATC issuing a crossing restriction at a fix (LEGGT 'AT' FL270) on the assigned RNAV arrival that differed from the STAR published restriction (LEGGT 'AT or ABOVE' FL270) without emphasizing the change.To prevent this recurrence; we as a crew will be much more diligent in cross-checking altitudes in the FMS flight plan whenever crossing restrictions are issued by ATC; specifically when differentiating between crossing 'AT' vs 'AT or ABOVE'.  We will also query ATC if there are any questions when the clearance issued by ATC contradicts published altitudes or crossing restrictions in a procedure. I also think it would be beneficial for all involved if there was a way for ATC to emphasize crossing altitude instructions whenever they differ from published altitudes or crossing restrictions in the SID/STAR.  I think something along the lines of 'descend via MAATY1 except cross LEGGT AT FL270' may have helped in this scenario; though it is possible that may be too redundant or possibly be cause for additional confusion for other crews/controllers.  It comes down finding a way to differentiate between the assigned clearance of crossing a fix 'AT' compared to the published restriction'AT or ABOVE'.
While flying the MAATY1 arrival yesterday into TPA; we were given an altitude restrictions to 'cross LEGGT at FL270.'  27;000 was entered into the altitude preselector and FL270 was already pre-programmed into the FMS; as this is the altitude shown on the arrival. VNAV on the auto-pilot was armed; and we intercepted the VPATH to FL270. We were given a frequency change and when I checked in I said that we were '28;500 descending to 27;000 at LEGGT'.  The controller said that we had already crossed LEGGT and asked what our previously assigned altitude restriction was. I saw that we were on the Glide Path to 27;000 and wasn't sure immediately why we hadn't arrived at 27;000 at LEGGT.  I said that 'we were assigned 27;000 at LEGGT and that we were having an FMS issue.'  The detail that the crew failed to notice was that the FL270 is an AT OR ABOVE altitude as depicted on the arrival plate and as pre-programmed in the FMS.  We used the VNAV mode on the autopilot and the display on the G5000 appeared to be bringing us to 27;000 at LEGGT. We were then cleared to FL190 and told to expedite; which we did.  Later we were given MAATY at 13;000 and 250kts and the FMS functioned as expected.  After taking some time to diagnose the issue; we learned that the FMS was pre-programmed to cross LEGGT AT OR ABOVE FL270.  Not to cross AT FL270 as instructed. After thoroughly debriefing the flight; there are multiple factors as to why I believe this event occurred.1) The implementation of the new arrivals from the Florida Metroplex and the similarities (and subtle differences) between the MAATY1 and the FOOXX5 arrivals.2) Even though the altitudes in the FMS were briefed; the crew failed to notice the altitude constraint difference between the pre-loaded altitudes in the FMS and the clearance received from ATC.3) ATC used an altitude restriction from the FOOXX5 as an altitude restriction on the MAATY1.4) ATC did not emphasize the difference between the clearance and the published arrival.1) The pilots have been flying the FOOXX5 arrival regularly for many years.  The FOOXX5 says to EXPECT LEGGT at FL270; and it was very common for the controllers to issue this restriction. We would always enter FL270 AT LEGGT manually into the FMS. By entering the altitude manually; we always create an 'AT' altitude. Since the new procedure shows the same altitude at the same point I think that it is easy for the crew to assume that the FMS will cross LEGGT at FL270; just as it always has. However; 'AT OR ABOVE' FL270 is now pre-programmed in the FMS and the auto-pilot will not cross LEGGT at FL270 like it did previously.  It now requires re-entering the altitude into the FMS as an 'AT' altitude if the controller issues the 'cross LEGGT 'AT' FL270' like they have done for many years.  2) To prevent this from happening in the future; the crew must be sure to cross-check the constraints ('AT OR ABOVE' vs 'AT' altitudes) for the arrival.  The crew must also be aware that ATC altitude restrictions MAY NOT coincide with the published arrival procedures and must be sure to cross-check each clearance.3) There are similarities between the FOOXX5 and the MAATY1 in that they use some of the same fixes (HEVVN and LEGGT).  The published altitudes at LEGGT are subtly different.  FOOXX5 publishes expect LEGGT 'AT' FL270 and MAATY1 publishes cross LEGGT 'AT OR ABOVE' FL270.  The controller used the altitude constraint from the FOOXX5 as opposed to the altitude constraint on the MAATY1. The controller that issued 'cross LEGGT at FL270' may have issued that clearance hundreds of times in his career from the FOOXX5 and may not think anything of it; even though this clearance differs from the published altitude in the MAATY1. With MAATY1 programmed; the FMS in our aircraft schedules the crossing of LEGGT somewhere between FL280 and FL290 since it is projecting a 3 degree glidepath to GOJOE between FL260 and FL210 and MAATY AT 13;000. To make our FMS cross LEGGT 'AT' FL270; it requires reprogramming the altitude restriction in the FMS.  This is easily missed since the altitude displayed next to LEGGT is FL270 within the FMS.  4) If a clearance differs from the published arrival procedure; it would be helpful if ATC would emphasize that difference. For example 'Descend via the MAATY1 EXCEPT cross LEGGT at FL270.' Going forward the crew will also be sure to question ATC when a clearance does not match a published procedure.
Flight crew reported they failed to meet a crossing restriction while descending on a new arrival into TPA after misinterpreting the crossing restrictions and ATC clearance. Issue was further complicated by the use of the same fixes across multiple arrivals.