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Flight crew of a widebody transport lost control of the aircraft when the aircraft suddenly started climbing with airspeed rising during high altitude cruise flight between thunderstorm buildups.
| Attributes | |
| ACN | 335732 |
| Time | |
| Date | 199605 |
| Day | Mon |
| Local Time Of Day | 1801 To 2400 |
| Place | |
| Locale Reference | atc facility : rzc |
| State Reference | AR |
| Altitude | msl bound lower : 36500 msl bound upper : 40000 |
| Environment | |
| Flight Conditions | Mixed |
| Light | Night |
| Aircraft 1 | |
| Controlling Facilities | artcc : zme |
| Operator | common carrier : air carrier |
| Make Model Name | Commercial Fixed Wing |
| Operating Under FAR Part | Part 121 |
| Navigation In Use | Other |
| Flight Phase | cruise other |
| Flight Plan | IFR |
| Person 1 | |
| Affiliation | company : air carrier |
| Function | flight crew : first officer |
| Qualification | pilot : atp |
| Experience | flight time last 90 days : 200 flight time total : 8500 flight time type : 200 |
| ASRS Report | 335732 |
| Person 2 | |
| Affiliation | company : air carrier |
| Function | flight crew : captain oversight : pic |
| Qualification | pilot : atp |
| Events | |
| Anomaly | altitude deviation : excursion from assigned altitude inflight encounter : weather non adherence : clearance other anomaly other anomaly other |
| Independent Detector | other flight crewa |
| Resolutory Action | flight crew : regained aircraft control flight crew : returned to intended course or assigned course |
| Consequence | Other |
| Supplementary | |
| Primary Problem | Weather |
| Air Traffic Incident | Pilot Deviation |
Narrative:
The aircraft was in cruise at FL390. The radar showed what appeared to be a clear path through a line of thunderstorms. The storm was developing on the left and right side of the aircraft flight path. We were on top of all the WX and could see the stars all the way down to the horizon. The aircraft went from smooth flight to mach buffeting instantly. The captain turned off the autoplt and allowed the aircraft to pitch up as I pulled the throttles back to 65 percent. The altitude climbed to approximately 40000 ft, while the aircraft was still in mach buffet. The airspeed dropped 60 KTS just as quickly as it hit mach buffet. I yelled, 'airspeed' just as the captain pushed the nose over and I added power to go around thrust. The airspeed recovered at about FL365, as I recall, although the captain thought it was closer to FL380. The 1000+ ft drop sent some of the flight attendants and maintenance personnel in the rear of the aircraft to the ceiling and held them there for 10-15 seconds. No one broke any bones, but the cause of any bruises and a great deal of anxiety can be largely attributed to the fact that, although the seat belt sign was on, the experienced cabin crew ignored the sign and had not stowed much of their luggage. The flight was operating as a far part 91 ferry back to our home base. Therefore, it appears some of the cabin crew did not take the fact that the captain had the seat belt sign on seriously. Also, I got the impression that the fear in some cabin crew members generated more fear in other cabin crew members. I will never know for sure if the gap between storm cells closed too quickly, the WX developed rapidly from below, or if the anvil of the storm cell on the left was pushed into our flight path by the 130 KT jetstream. I believe the later to be the case, since we could hear ice pellets on the windshield during most of the turbulence. In the future I will give a storm cell more distance and make the cabin crew buckle up.
Original NASA ASRS Text
Title: FLC OF A WDB LOST CTL OF THE ACFT WHEN THE ACFT SUDDENLY STARTED CLBING WITH AIRSPD RISING DURING HIGH ALT CRUISE FLT BTWN TSTM BUILDUPS.
Narrative: THE ACFT WAS IN CRUISE AT FL390. THE RADAR SHOWED WHAT APPEARED TO BE A CLR PATH THROUGH A LINE OF TSTMS. THE STORM WAS DEVELOPING ON THE L AND R SIDE OF THE ACFT FLT PATH. WE WERE ON TOP OF ALL THE WX AND COULD SEE THE STARS ALL THE WAY DOWN TO THE HORIZON. THE ACFT WENT FROM SMOOTH FLT TO MACH BUFFETING INSTANTLY. THE CAPT TURNED OFF THE AUTOPLT AND ALLOWED THE ACFT TO PITCH UP AS I PULLED THE THROTTLES BACK TO 65 PERCENT. THE ALT CLBED TO APPROX 40000 FT, WHILE THE ACFT WAS STILL IN MACH BUFFET. THE AIRSPD DROPPED 60 KTS JUST AS QUICKLY AS IT HIT MACH BUFFET. I YELLED, 'AIRSPD' JUST AS THE CAPT PUSHED THE NOSE OVER AND I ADDED PWR TO GAR THRUST. THE AIRSPD RECOVERED AT ABOUT FL365, AS I RECALL, ALTHOUGH THE CAPT THOUGHT IT WAS CLOSER TO FL380. THE 1000+ FT DROP SENT SOME OF THE FLT ATTENDANTS AND MAINT PERSONNEL IN THE REAR OF THE ACFT TO THE CEILING AND HELD THEM THERE FOR 10-15 SECONDS. NO ONE BROKE ANY BONES, BUT THE CAUSE OF ANY BRUISES AND A GREAT DEAL OF ANXIETY CAN BE LARGELY ATTRIBUTED TO THE FACT THAT, ALTHOUGH THE SEAT BELT SIGN WAS ON, THE EXPERIENCED CABIN CREW IGNORED THE SIGN AND HAD NOT STOWED MUCH OF THEIR LUGGAGE. THE FLT WAS OPERATING AS A FAR PART 91 FERRY BACK TO OUR HOME BASE. THEREFORE, IT APPEARS SOME OF THE CABIN CREW DID NOT TAKE THE FACT THAT THE CAPT HAD THE SEAT BELT SIGN ON SERIOUSLY. ALSO, I GOT THE IMPRESSION THAT THE FEAR IN SOME CABIN CREW MEMBERS GENERATED MORE FEAR IN OTHER CABIN CREW MEMBERS. I WILL NEVER KNOW FOR SURE IF THE GAP BTWN STORM CELLS CLOSED TOO QUICKLY, THE WX DEVELOPED RAPIDLY FROM BELOW, OR IF THE ANVIL OF THE STORM CELL ON THE L WAS PUSHED INTO OUR FLT PATH BY THE 130 KT JETSTREAM. I BELIEVE THE LATER TO BE THE CASE, SINCE WE COULD HEAR ICE PELLETS ON THE WINDSHIELD DURING MOST OF THE TURB. IN THE FUTURE I WILL GIVE A STORM CELL MORE DISTANCE AND MAKE THE CABIN CREW BUCKLE UP.
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.