Narrative:

I was the international officer on the flight from europe to jfk. We were in a widebody transport, I was in the center jump seat, and it was the captain's leg. It was XA00 local, receiving radar vector about 20 mi from the initial approach fix for ILS runway 22L rolling out on a base, leveling at 4000'. WX was IMC, rain showers and increasing turbulence. The radar showed the strongest returns (red) ahead and to the left with turbs increasing to mod. The captain said he was unsure if the radar was painting an accurate picture and unsure of what to do. ATC gave us a descent to 3000', then a left turn for a dog leg to an extended final. The captain said that he didn't think he really wanted to turn left, but set the new heading in the autoplt anyway. We were now right in the middle of the red area and turbs were quite strong. It took the autoplt a few seconds to start the turn due to the turbulence. The captain didn't like the way the autoplt was starting the turn and quickly turned it off. At the same time the strongest of the turbs hit and the captain started overcontrolling. The copilot recommended just going straight ahead and the captain acknowledged as a good idea. The copilot called ATC for the deviation. In a matter of 15 seconds of hand flying the aircraft we were 45 degree angle of bank to the left and 10 degrees nose down. I said 'angle of bank,' then the altitude at which time both the captain and copilot added power as we busted 3000'. The captain righted the aircraft, but the nose pitched way up. He was having trouble keeping the wing from going to the right, caused more by vertigo than by turbulence. The altitude and airspeed started to really climb as we drifted to the right. ATC was trying to get us to turn back on course, then finally asked what our altitude. Was. The captain pulled the power back and got the nose back down around 4600'. At that point I recommended that the captain turn the autoplt back on. The captain acknowledged very positively and quickly turned it on. The autoplt leveled the aircraft and everything got under control in a second. A minute later we were through the rain cell and turbulence. We got back on course and landed west/O any other problems. This whole thing could have been avoided if the captain had not gone into the red area. Second, the autoplt was working good before he turned it off. Finally, the copilot didn't help all that much when he saw the captain losing control. Callback conversation with reporter revealed the following: determined this was first time these 2 crew members had flown with this captain, but he had made perfect CAT III into ory the day before, so they were surprised when he had control problems on the return. Does not understand why captain elected to fly into red depicted on radar as this radar is good and red means turbulence. Altitude loss was so fast feels sure they hit the main downdraft at front of storm. Thinks flight crew fatigue may have affected captain's decision. Supplemental information from acn 98108: I tend to believe it was a combination of the moderate turbulence and the disconnecting of the autoplt too soon and the large inputs of control to the aircraft that caused this problem.

Related reports:

Google
 

Original NASA ASRS Text

Title: ACR WDB INFLT WX ENCOUNTER TURBULENCE ALT OVERSHOT ON DESCENT.

Narrative: I WAS THE INTERNATIONAL OFFICER ON THE FLT FROM EUROPE TO JFK. WE WERE IN A WDB, I WAS IN THE CENTER JUMP SEAT, AND IT WAS THE CAPT'S LEG. IT WAS XA00 LCL, RECEIVING RADAR VECTOR ABOUT 20 MI FROM THE INITIAL APCH FIX FOR ILS RWY 22L ROLLING OUT ON A BASE, LEVELING AT 4000'. WX WAS IMC, RAIN SHOWERS AND INCREASING TURB. THE RADAR SHOWED THE STRONGEST RETURNS (RED) AHEAD AND TO THE LEFT WITH TURBS INCREASING TO MOD. THE CAPT SAID HE WAS UNSURE IF THE RADAR WAS PAINTING AN ACCURATE PICTURE AND UNSURE OF WHAT TO DO. ATC GAVE US A DSCNT TO 3000', THEN A LEFT TURN FOR A DOG LEG TO AN EXTENDED FINAL. THE CAPT SAID THAT HE DIDN'T THINK HE REALLY WANTED TO TURN LEFT, BUT SET THE NEW HDG IN THE AUTOPLT ANYWAY. WE WERE NOW RIGHT IN THE MIDDLE OF THE RED AREA AND TURBS WERE QUITE STRONG. IT TOOK THE AUTOPLT A FEW SECS TO START THE TURN DUE TO THE TURB. THE CAPT DIDN'T LIKE THE WAY THE AUTOPLT WAS STARTING THE TURN AND QUICKLY TURNED IT OFF. AT THE SAME TIME THE STRONGEST OF THE TURBS HIT AND THE CAPT STARTED OVERCONTROLLING. THE COPLT RECOMMENDED JUST GOING STRAIGHT AHEAD AND THE CAPT ACKNOWLEDGED AS A GOOD IDEA. THE COPLT CALLED ATC FOR THE DEVIATION. IN A MATTER OF 15 SECS OF HAND FLYING THE ACFT WE WERE 45 DEG ANGLE OF BANK TO THE LEFT AND 10 DEGS NOSE DOWN. I SAID 'ANGLE OF BANK,' THEN THE ALT AT WHICH TIME BOTH THE CAPT AND COPLT ADDED PWR AS WE BUSTED 3000'. THE CAPT RIGHTED THE ACFT, BUT THE NOSE PITCHED WAY UP. HE WAS HAVING TROUBLE KEEPING THE WING FROM GOING TO THE RIGHT, CAUSED MORE BY VERTIGO THAN BY TURB. THE ALT AND AIRSPD STARTED TO REALLY CLB AS WE DRIFTED TO THE RIGHT. ATC WAS TRYING TO GET US TO TURN BACK ON COURSE, THEN FINALLY ASKED WHAT OUR ALT. WAS. THE CAPT PULLED THE PWR BACK AND GOT THE NOSE BACK DOWN AROUND 4600'. AT THAT POINT I RECOMMENDED THAT THE CAPT TURN THE AUTOPLT BACK ON. THE CAPT ACKNOWLEDGED VERY POSITIVELY AND QUICKLY TURNED IT ON. THE AUTOPLT LEVELED THE ACFT AND EVERYTHING GOT UNDER CONTROL IN A SECOND. A MINUTE LATER WE WERE THROUGH THE RAIN CELL AND TURB. WE GOT BACK ON COURSE AND LANDED W/O ANY OTHER PROBS. THIS WHOLE THING COULD HAVE BEEN AVOIDED IF THE CAPT HAD NOT GONE INTO THE RED AREA. SECOND, THE AUTOPLT WAS WORKING GOOD BEFORE HE TURNED IT OFF. FINALLY, THE COPLT DIDN'T HELP ALL THAT MUCH WHEN HE SAW THE CAPT LOSING CONTROL. CALLBACK CONVERSATION WITH RPTR REVEALED THE FOLLOWING: DETERMINED THIS WAS FIRST TIME THESE 2 CREW MEMBERS HAD FLOWN WITH THIS CAPT, BUT HE HAD MADE PERFECT CAT III INTO ORY THE DAY BEFORE, SO THEY WERE SURPRISED WHEN HE HAD CONTROL PROBS ON THE RETURN. DOES NOT UNDERSTAND WHY CAPT ELECTED TO FLY INTO RED DEPICTED ON RADAR AS THIS RADAR IS GOOD AND RED MEANS TURB. ALT LOSS WAS SO FAST FEELS SURE THEY HIT THE MAIN DOWNDRAFT AT FRONT OF STORM. THINKS FLT CREW FATIGUE MAY HAVE AFFECTED CAPT'S DECISION. SUPPLEMENTAL INFO FROM ACN 98108: I TEND TO BELIEVE IT WAS A COMBINATION OF THE MODERATE TURB AND THE DISCONNECTING OF THE AUTOPLT TOO SOON AND THE LARGE INPUTS OF CONTROL TO THE ACFT THAT CAUSED THIS PROB.

Data retrieved from NASA's ASRS site as of August 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.