 |
37000 Feet | Browse and search NASA's Aviation Safety Reporting System |
|
Altitude crossing restr - the flight crew did not realize that the VNAV mode of the autoplt had disengaged until ARTCC controller questioned why they were so high.
| Attributes | |
| ACN | 300133 |
| Time | |
| Date | 199503 |
| Day | Wed |
| Local Time Of Day | 1801 To 2400 |
| Place | |
| Locale Reference | atc facility : pxt |
| State Reference | MD |
| Altitude | msl bound lower : 24000 msl bound upper : 33000 |
| Environment | |
| Flight Conditions | VMC |
| Light | Daylight |
| Aircraft 1 | |
| Controlling Facilities | artcc : zny |
| Operator | common carrier : air carrier |
| Make Model Name | Commercial Fixed Wing |
| Operating Under FAR Part | Part 121 |
| Navigation In Use | Other Other |
| Flight Phase | cruise other |
| Route In Use | arrival other arrival star : star enroute airway : zny |
| Flight Plan | IFR |
| Person 1 | |
| Affiliation | company : air carrier |
| Function | flight crew : captain oversight : pic |
| Qualification | pilot : instrument pilot : flight engineer pilot : commercial pilot : atp |
| Experience | flight time last 90 days : 211 flight time total : 24000 flight time type : 4800 |
| ASRS Report | 300133 |
| Person 2 | |
| Affiliation | company : air carrier |
| Function | flight crew : first officer |
| Qualification | pilot : commercial pilot : instrument |
| Events | |
| Anomaly | aircraft equipment problem : less severe altitude deviation : crossing restriction not met non adherence : clearance |
| Independent Detector | other controllera |
| Resolutory Action | controller : issued new clearance other other |
| Consequence | Other |
| Supplementary | |
| Primary Problem | Flight Crew Human Performance |
| Air Traffic Incident | Pilot Deviation |
Narrative:
While inbound to ewr on the ward 4 STAR (with first officer flying the aircraft) at FL330 we were cleared to cross ridgy at FL240. The crossing restr was placed in the FMC, a 240 in the altitude window (aircraft in VNAV and LNAV modes). I (captain) contacted company maintenance about a slight engine problem on our #2 VHF. (First officer monitoring center frequency on #1 VHF). After returning to center frequency the center called and asked for our altitude. I told them we were at FL330 with clearance to FL240. He then asked what our clearance was and I checked the FMC and saw that we were past ridgy. I told him the aircraft had not started down. He then cleared us to FL190 with no further problems. The VNAV mode had tripped off and the aircraft had not started the descent as programmed to cross ridgy at FL240. Neither first officer nor I had detected that VNAV had tripped off.
Original NASA ASRS Text
Title: ALT XING RESTR - THE FLC DID NOT REALIZE THAT THE VNAV MODE OF THE AUTOPLT HAD DISENGAGED UNTIL ARTCC CTLR QUESTIONED WHY THEY WERE SO HIGH.
Narrative: WHILE INBOUND TO EWR ON THE WARD 4 STAR (WITH FO FLYING THE ACFT) AT FL330 WE WERE CLRED TO CROSS RIDGY AT FL240. THE XING RESTR WAS PLACED IN THE FMC, A 240 IN THE ALT WINDOW (ACFT IN VNAV AND LNAV MODES). I (CAPT) CONTACTED COMPANY MAINT ABOUT A SLIGHT ENG PROB ON OUR #2 VHF. (FO MONITORING CTR FREQ ON #1 VHF). AFTER RETURNING TO CTR FREQ THE CTR CALLED AND ASKED FOR OUR ALT. I TOLD THEM WE WERE AT FL330 WITH CLRNC TO FL240. HE THEN ASKED WHAT OUR CLRNC WAS AND I CHKED THE FMC AND SAW THAT WE WERE PAST RIDGY. I TOLD HIM THE ACFT HAD NOT STARTED DOWN. HE THEN CLRED US TO FL190 WITH NO FURTHER PROBS. THE VNAV MODE HAD TRIPPED OFF AND THE ACFT HAD NOT STARTED THE DSCNT AS PROGRAMMED TO CROSS RIDGY AT FL240. NEITHER FO NOR I HAD DETECTED THAT VNAV HAD TRIPPED OFF.
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.