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First officer of air carrier small transport aircraft undershot descent clearance altitude due loss of aircraft control in thunderstorm.
| Attributes | |
| ACN | 211878 |
| Time | |
| Date | 199206 |
| Day | Tue |
| Local Time Of Day | 1801 To 2400 |
| Place | |
| Locale Reference | atc facility : orl |
| State Reference | FL |
| Altitude | msl bound lower : 10000 msl bound upper : 12000 |
| Environment | |
| Flight Conditions | IMC |
| Light | Daylight |
| Aircraft 1 | |
| Controlling Facilities | tower : cef |
| Operator | common carrier : air carrier |
| Make Model Name | Small Transport, Low Wing, 2 Turboprop Eng |
| Flight Phase | descent other |
| Route In Use | enroute airway : zma |
| Flight Plan | IFR |
| Person 1 | |
| Affiliation | company : air carrier |
| Function | flight crew : first officer |
| Qualification | pilot : atp |
| Experience | flight time last 90 days : 120 flight time total : 4300 flight time type : 25 |
| ASRS Report | 211878 |
| Person 2 | |
| Affiliation | company : air carrier |
| Function | flight crew : captain oversight : pic |
| Qualification | pilot : atp |
| Events | |
| Anomaly | altitude deviation : undershoot inflight encounter : weather non adherence : clearance other anomaly |
| Independent Detector | other flight crewa |
| Resolutory Action | controller : issued new clearance flight crew : declared emergency flight crew : regained aircraft control other |
| Consequence | Other |
| Supplementary | |
| Primary Problem | Aircraft |
Narrative:
While inbound to mco ZMA advised mco not accepting inbounds due to thunderstorm activity. ZMA issued all aircraft (including us) holding instructions at bairn. Our instructions included descent to 10000. After initiating descent from 14000 ft and without any warning on radar, we entered embedded thunderstorm cell. Reduced power in attempt to reduce airspeed to design maneuvering speed. Lift from cell would not allow descent without significantly increasing airspeed. Turbulence moderate to severe. Could maintain bank only within plus or minus 20 degrees. Miami requested increased descent and heading change. No cell definition on radar. Unable to comply for 2-3 mins until exited cell. Caused miami to turn other holding traffic back north to avoid conflict. Contributing factors: newly transitioned to small transport aircraft. Training on radar insufficient to recognize system degradation (attenuation). Radar written-up on arrival at mco as inoperative -- maintenance changed unit. Did not declare emergency -- probably should have.
Original NASA ASRS Text
Title: FO OF ACR SMT ACFT UNDERSHOT DSCNT CLRNC ALT DUE LOSS OF ACFT CTL IN TSTM.
Narrative: WHILE INBOUND TO MCO ZMA ADVISED MCO NOT ACCEPTING INBOUNDS DUE TO TSTM ACTIVITY. ZMA ISSUED ALL ACFT (INCLUDING US) HOLDING INSTRUCTIONS AT BAIRN. OUR INSTRUCTIONS INCLUDED DSCNT TO 10000. AFTER INITIATING DSCNT FROM 14000 FT AND WITHOUT ANY WARNING ON RADAR, WE ENTERED EMBEDDED TSTM CELL. REDUCED PWR IN ATTEMPT TO REDUCE AIRSPD TO DESIGN MANEUVERING SPD. LIFT FROM CELL WOULD NOT ALLOW DSCNT WITHOUT SIGNIFICANTLY INCREASING AIRSPD. TURB MODERATE TO SEVERE. COULD MAINTAIN BANK ONLY WITHIN PLUS OR MINUS 20 DEGS. MIAMI REQUESTED INCREASED DSCNT AND HDG CHANGE. NO CELL DEFINITION ON RADAR. UNABLE TO COMPLY FOR 2-3 MINS UNTIL EXITED CELL. CAUSED MIAMI TO TURN OTHER HOLDING TFC BACK N TO AVOID CONFLICT. CONTRIBUTING FACTORS: NEWLY TRANSITIONED TO SMT ACFT. TRAINING ON RADAR INSUFFICIENT TO RECOGNIZE SYS DEGRADATION (ATTENUATION). RADAR WRITTEN-UP ON ARR AT MCO AS INOP -- MAINT CHANGED UNIT. DID NOT DECLARE EMER -- PROBABLY SHOULD HAVE.
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.