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Air carrier crew of a large turbojet reported entering the tops of clouds in an area of convective weather. Aircraft was briefly upset; lost airspeed and altitude; but was eventually recovered.
| Attributes | |
| ACN | 1508657 |
| Time | |
| Date | 201801 |
| Local Time Of Day | 0601-1200 |
| Place | |
| Locale Reference | FLL.Airport |
| State Reference | FL |
| Environment | |
| Flight Conditions | VMC |
| Light | Daylight |
| Aircraft 1 | |
| Make Model Name | Large Transport Low Wing 2 Turbojet Eng |
| Operating Under FAR Part | Part 121 |
| Flight Phase | Cruise |
| Flight Plan | IFR |
| Person 1 | |
| Function | Captain Pilot Not Flying |
| Qualification | Flight Crew Air Transport Pilot (ATP) |
| Experience | Flight Crew Type 420 |
| Person 2 | |
| Function | First Officer Pilot Flying |
| Qualification | Flight Crew Air Transport Pilot (ATP) |
| Events | |
| Anomaly | Deviation - Altitude Excursion From Assigned Altitude Deviation - Procedural Published Material / Policy Deviation - Speed All Types Inflight Event / Encounter Weather / Turbulence Inflight Event / Encounter Loss Of Aircraft Control |
Narrative:
We were at FL390; on course; [and] there were rain showers and convective activity in the vicinity of fll at departure time. We were established on course and nearing the end of the convective area. We were approaching a very broad area of clouds; quite 'flat' on top; and not the typical appearance of any convective cell with vertical development. We had asked for a slight deviation from course (approximately 10 degrees left); to 'top' the cloud layer at its lowest point.the HUD indicated that we would just 'skim' the top of this area; radar was on and did not show any cell development using vertical-tilt mapping. I had the flight attendants remain in their seats since departure and updated them several times on suspected ride conditions; seat belt sign was on.we flew through the upper reaches of this broad cloud layer; and experienced immediate severe turbulence; including an mmo (maximum mach operating speed) exceedance (clacker); accompanied by gains and loss of altitude. Airspeed then started to deteriorate; and the first officer manually pitched down to prevent a high altitude stall event. Eventually; we recovered; but had lost approximately 800 feet.
Original NASA ASRS Text
Title: Air carrier crew of a large turbojet reported entering the tops of clouds in an area of convective weather. Aircraft was briefly upset; lost airspeed and altitude; but was eventually recovered.
Narrative: We were at FL390; on course; [and] there were rain showers and convective activity in the vicinity of FLL at departure time. We were established on course and nearing the end of the convective area. We were approaching a very broad area of clouds; quite 'flat' on top; and not the typical appearance of any convective cell with vertical development. We had asked for a slight deviation from course (approximately 10 degrees left); to 'top' the cloud layer at its lowest point.The HUD indicated that we would just 'skim' the top of this area; Radar was on and did not show any cell development using vertical-tilt mapping. I had the Flight Attendants remain in their seats since departure and updated them several times on suspected ride conditions; seat belt sign was on.We flew through the upper reaches of this broad cloud layer; and experienced immediate severe turbulence; including an MMO (Maximum Mach Operating Speed) exceedance (clacker); accompanied by gains and loss of altitude. Airspeed then started to deteriorate; and the First Officer manually pitched down to prevent a high altitude stall event. Eventually; we recovered; but had lost approximately 800 feet.
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.