Despite having insured proper FMS programming and monitoring available vertical path guidance; an E-...

Narrative:

The perf init (FMS page) was routinely programmed with a vmo/mmo/3.0 descent; the standard configuration. Upon descent we were cleared to cross wynde at 10;000 [ft]. I verified the correct TOD with the information in the FMS progress page as well as the vn (vertical navigation) data page; and began an early descent. Throughout; the descent I monitored our progress on the vn data page which consistently showed around -2;000 ft; as well as the pfd v-path indicator (showing below the required path for wynde). These (incorrect) indications continued all the way until we crossed wynde at 12;000 [ft]; which is 2;000 ft above the requirement. By the time the crew realized both indications; the vn data page and the pfd vpi; were false; there was insufficient time to make complete corrections; and we crossed at 12;000 [ft]. With increased use of opds and other heavily FMS dependent descents; I must seriously question the reliability of our equipment. The FMS is supposed to help manage the flight; it is now becoming a threat. Fmss have lied to the crews before. If this continues; flight crews will be forced to advise ATC that they are unable RNAV descents; because of FMS unreliability.

Original NASA ASRS Text

Title: Despite having insured proper FMS programming and monitoring available vertical path guidance; an E-145 flight crew failed to comply with the 10;000 FT crossing restriction at WYNDE waypoint while flying the WYNDE RNAV STAR to ORD.

Narrative: The Perf Init (FMS page) was routinely programmed with a Vmo/Mmo/3.0 descent; the standard configuration. Upon descent we were cleared to cross WYNDE at 10;000 [FT]. I verified the correct TOD with the information in the FMS progress page as well as the VN (Vertical Navigation) Data page; and began an early descent. Throughout; the descent I monitored our progress on the VN Data page which consistently showed around -2;000 FT; as well as the PFD V-path indicator (showing below the required path for WYNDE). These (incorrect) indications continued all the way until we crossed WYNDE at 12;000 [FT]; which is 2;000 FT above the requirement. By the time the crew realized both indications; the VN Data page and the PFD VPI; were false; there was insufficient time to make complete corrections; and we crossed at 12;000 [FT]. With increased use of OPDs and other heavily FMS dependent descents; I must seriously question the reliability of our equipment. The FMS is supposed to help manage the flight; it is now becoming a threat. FMSs have lied to the crews before. If this continues; flight crews will be forced to advise ATC that they are unable RNAV descents; because of FMS unreliability.

Data retrieved from NASA's ASRS site as of July 2013 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.

Attributes
ACN	1077966
Time
Date	201303
Local Time Of Day	1201-1800
Place
Locale Reference	C90.TRACON
State Reference	IL
Aircraft 1
Make Model Name	EMB ERJ 145 ER/LR
Operating Under FAR Part	Part 121
Flight Phase	Descent
Route In Use	STAR WYNDE
Flight Plan	IFR
Component
Aircraft Component	FMS/FMC
Person 1
Function	Captain Pilot Flying
Qualification	Flight Crew Air Transport Pilot (ATP)
Events
Anomaly	Deviation - Altitude Crossing Restriction Not Met Deviation - Procedural Clearance Deviation - Procedural Published Material / Policy

Despite having insured proper FMS programming and monitoring available vertical path guidance; an E-145 flight crew failed to comply with the 10;000 ft crossing restriction at wynde waypoint while flying the wynde RNAV STAR to ord.