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Flying a VNAV descent on the lga, ny, localizer runway 13 approach, B767 crew finds themselves 400 ft below the required altitude at the FAF.
| Attributes | |
| ACN | 567523 |
| Time | |
| Date | 200212 |
| Day | Tue |
| Local Time Of Day | 1201 To 1800 |
| Place | |
| Locale Reference | atc facility : n90.tracon |
| State Reference | NY |
| Altitude | msl bound lower : 1100 msl bound upper : 1200 |
| Environment | |
| Flight Conditions | VMC |
| Light | Night |
| Aircraft 1 | |
| Controlling Facilities | tracon : n90.tracon |
| Operator | common carrier : air carrier |
| Make Model Name | B767-200 |
| Operating Under FAR Part | Part 121 |
| Navigation In Use | ils localizer & glide slope : 31 other |
| Flight Phase | descent : approach |
| Flight Plan | IFR |
| Person 1 | |
| Affiliation | company : air carrier |
| Function | flight crew : first officer |
| Qualification | pilot : atp |
| Experience | flight time last 90 days : 105 flight time total : 6200 flight time type : 2400 |
| ASRS Report | 567523 |
| Person 2 | |
| Affiliation | company : air carrier |
| Function | flight crew : captain oversight : pic |
| Events | |
| Anomaly | aircraft equipment problem : less severe altitude deviation : overshoot altitude deviation : crossing restriction not met non adherence : published procedure non adherence : far non adherence : clearance other spatial deviation |
| Independent Detector | atc equipment : msaw other controllerb other flight crewa |
| Resolutory Action | flight crew : returned to original clearance flight crew : overrode automation flight crew : became reoriented none taken : detected after the fact |
| Supplementary | |
| Problem Areas | Aircraft ATC Human Performance Flight Crew Human Performance |
| Primary Problem | Flight Crew Human Performance |
Narrative:
We were cleared for localizer runway 31 approach into lga approximately 10 mi at approximately 2000 ft MSL. Procedures were accomplished in accordance with the operations manual for the B767 for a VNAV descent to runway 31. VNAV was selected and 'VNAV path' was captured on the ADI with the autoplt and autothrottles engaged. The aircraft began a descent, and reduced power to follow the VNAV path horizontal bar on the ADI. At fabry FAF, the air crew noted the aircraft was at approximately 1200 ft (400 ft lower than the 1600 FAF altitude) and that the aircraft was 10 KTS slower than the selected MCP airspeed window (approximately 142 KTS). As first officer flying, I disconnected the autoplt and autothrottles and proceeded to fly the aircraft manually to the proper glide path and airspeed. Just after or as I took control of the aircraft, lga approach control gave us a low altitude alert and told us to check our barometric altimeter settings. The aircraft landed uneventfully and without further incident. Note: the B767-200 model is notorious for having a difficult time following VNAV path profiles and keeping proper airspeed on arrival profiles.
Original NASA ASRS Text
Title: FLYING A VNAV DSCNT ON THE LGA, NY, LOC RWY 13 APCH, B767 CREW FINDS THEMSELVES 400 FT BELOW THE REQUIRED ALT AT THE FAF.
Narrative: WE WERE CLRED FOR LOC RWY 31 APCH INTO LGA APPROX 10 MI AT APPROX 2000 FT MSL. PROCS WERE ACCOMPLISHED IN ACCORDANCE WITH THE OPS MANUAL FOR THE B767 FOR A VNAV DSCNT TO RWY 31. VNAV WAS SELECTED AND 'VNAV PATH' WAS CAPTURED ON THE ADI WITH THE AUTOPLT AND AUTOTHROTTLES ENGAGED. THE ACFT BEGAN A DSCNT, AND REDUCED PWR TO FOLLOW THE VNAV PATH HORIZ BAR ON THE ADI. AT FABRY FAF, THE AIR CREW NOTED THE ACFT WAS AT APPROX 1200 FT (400 FT LOWER THAN THE 1600 FAF ALT) AND THAT THE ACFT WAS 10 KTS SLOWER THAN THE SELECTED MCP AIRSPD WINDOW (APPROX 142 KTS). AS FO FLYING, I DISCONNECTED THE AUTOPLT AND AUTOTHROTTLES AND PROCEEDED TO FLY THE ACFT MANUALLY TO THE PROPER GLIDE PATH AND AIRSPD. JUST AFTER OR AS I TOOK CTL OF THE ACFT, LGA APCH CTL GAVE US A LOW ALT ALERT AND TOLD US TO CHK OUR BAROMETRIC ALTIMETER SETTINGS. THE ACFT LANDED UNEVENTFULLY AND WITHOUT FURTHER INCIDENT. NOTE: THE B767-200 MODEL IS NOTORIOUS FOR HAVING A DIFFICULT TIME FOLLOWING VNAV PATH PROFILES AND KEEPING PROPER AIRSPD ON ARR PROFILES.
Data retrieved from NASA's ASRS site as of July 2007 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.