 |
37000 Feet | Browse and search NASA's Aviation Safety Reporting System |
|
An air carrier MD80 flight crew decides to use the airspeed hold mode to descend 1000 ft and is surprised when the aircraft initially climbs instead and then starts a too steep descent and goes below the assigned altitude.
| Attributes | |
| ACN | 370970 |
| Time | |
| Date | 199706 |
| Day | Tue |
| Local Time Of Day | 1201 To 1800 |
| Place | |
| Locale Reference | atc facility : dbq |
| State Reference | IA |
| Altitude | msl bound lower : 27500 msl bound upper : 28000 |
| Environment | |
| Light | Daylight |
| Aircraft 1 | |
| Controlling Facilities | artcc : zau |
| Operator | common carrier : air carrier |
| Make Model Name | MD-80 Super 80 |
| Operating Under FAR Part | Part 121 |
| Navigation In Use | Other |
| Flight Phase | descent other |
| Flight Plan | IFR |
| Person 1 | |
| Affiliation | company : air carrier |
| Function | flight crew : captain oversight : pic |
| Qualification | pilot : atp |
| ASRS Report | 370970 |
| Person 2 | |
| Affiliation | company : air carrier |
| Function | flight crew : first officer |
| Qualification | pilot : commercial pilot : instrument |
| ASRS Report | 370971 |
| Events | |
| Anomaly | altitude deviation : overshoot non adherence : clearance non adherence : far |
| Independent Detector | aircraft equipment other aircraft equipment : unspecified other flight crewa |
| Resolutory Action | flight crew : returned to intended course or assigned course |
| Consequence | Other |
| Supplementary | |
| Primary Problem | Flight Crew Human Performance |
| Air Traffic Incident | Pilot Deviation |
Narrative:
Level at FL290, cleared to descend to FL280. Captain used IAS level at FL290 with captain flying. Cleared descend to FL280. Used IAS initially and aircraft pitched up then down after a few seconds. Rate of descent was excessive for 1000 ft descent. Captain turned autoplt off and stopped descent at about FL275-FL276 and returned aircraft to FL280. No comment from center or conflicts known. In retrospect vertical speed is better when only descending 1000 ft.
Original NASA ASRS Text
Title: AN ACR MD80 FLC DECIDES TO USE THE AIRSPD HOLD MODE TO DSND 1000 FT AND IS SURPRISED WHEN THE ACFT INITIALLY CLBS INSTEAD AND THEN STARTS A TOO STEEP DSCNT AND GOES BELOW THE ASSIGNED ALT.
Narrative: LEVEL AT FL290, CLRED TO DSND TO FL280. CAPT USED IAS LEVEL AT FL290 WITH CAPT FLYING. CLRED DSND TO FL280. USED IAS INITIALLY AND ACFT PITCHED UP THEN DOWN AFTER A FEW SECONDS. RATE OF DSCNT WAS EXCESSIVE FOR 1000 FT DSCNT. CAPT TURNED AUTOPLT OFF AND STOPPED DSCNT AT ABOUT FL275-FL276 AND RETURNED ACFT TO FL280. NO COMMENT FROM CTR OR CONFLICTS KNOWN. IN RETROSPECT VERT SPD IS BETTER WHEN ONLY DSNDING 1000 FT.
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.