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A B767-300 crew reported they were unable to descend on a profile descent and cross at the altitude constraints. The efficient winglets reportedly would not allow a steep enough descent.
| Attributes | |
| ACN | 1173131 |
| Time | |
| Date | 201405 |
| Local Time Of Day | 1201-1800 |
| Place | |
| Locale Reference | ZZZ.ARTCC |
| State Reference | US |
| Environment | |
| Flight Conditions | Mixed |
| Light | Daylight |
| Aircraft 1 | |
| Make Model Name | B767-300 and 300 ER |
| Operating Under FAR Part | Part 121 |
| Flight Phase | Descent |
| Route In Use | Other On SID/STAR |
| Flight Plan | IFR |
| Component | |
| Aircraft Component | Winglet |
| Person 1 | |
| Function | Captain Pilot Flying |
| Qualification | Flight Crew Air Transport Pilot (ATP) |
| Person 2 | |
| Function | Pilot Not Flying First Officer |
| Events | |
| Anomaly | ATC Issue All Types Deviation - Altitude Crossing Restriction Not Met Deviation - Procedural Published Material / Policy Deviation - Procedural Clearance |
Narrative:
Cleared for arrival. Set 4;500 ft in altitude window for lowest altitude; not cleared for a runway so put altitude prior to runway selection. In LNAV and VNAV. Crossed the first constraint below 16;000 ft and headed to the next waypoint. VNAV could not descend to cross below 11;000 ft per STAR with throttles at idle and speed brake fully extended. Crossed at 11;800 ft. Noted that this is a common problem since winglet installation. Aircraft later leveled at 8;200 ft and would not descend in VNAV to follow STAR restrictions. Selected fl change and managed restrictions manually. Landed without incident and ATC did not mention this as a problem but felt we should report it. You have 4.1 miles to cross 5;000 ft lower and VNAV could not manage this. Could not make the extra 800 ft using speed brakes at idle either.
Original NASA ASRS Text
Title: A B767-300 crew reported they were unable to descend on a profile descent and cross at the altitude constraints. The efficient winglets reportedly would not allow a steep enough descent.
Narrative: Cleared for arrival. Set 4;500 FT in altitude window for lowest altitude; not cleared for a runway so put ALT prior to runway selection. In LNAV and VNAV. Crossed the first constraint below 16;000 FT and headed to the next waypoint. VNAV could not descend to cross below 11;000 FT per STAR with throttles at idle and speed brake fully extended. Crossed at 11;800 FT. Noted that this is a common problem since winglet installation. Aircraft later leveled at 8;200 FT and would not descend in VNAV to follow STAR restrictions. Selected FL change and managed restrictions manually. Landed without incident and ATC did not mention this as a problem but felt we should report it. You have 4.1 miles to cross 5;000 FT lower and VNAV could not manage this. Could not make the extra 800 FT using speed brakes at idle either.
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.