Narrative:

During climb out from the airport area we were vectored by ATC through an area of weather to the northeast of the airport. We were vectored between two moderate cells that were painting red on our radar. There was little turbulence associated with the weather. I thought the vectors turned out quite well. We emerged out of the weather on top for a few minutes and it looked as though it would be clear ahead with perhaps just some stratus above as there was no significant weather being painted on our radar other than just a bit of green. ATC informed us that there would be nothing worse than a bit of light chop as we continued our climb through approximately 16;000 ft. I informed our number 1 flight attendant that they could begin their service but was told they would wait an additional 10 minutes before beginning; so they fortunately remained seated. A few minutes after clearing the significant weather that we had passed climbing through approximately FL220; we encountered about 7-10 seconds of violent up and down pulsating of the aircraft. Shortly after this encounter the autopilot and auto throttles were turned off. It was during this time; that the first officer's airspeed indicated a significant loss of airspeed; perhaps going down to 240 KTS. His altimeter indicated that we were descending; but the captain's altimeter indicated a steady climb and a speed of 300 KTS. If I recall; the first officer began to chase the airspeed and altitude which resulted in a result opposite to which we needed as my airspeed and the standby airspeed both indicated increasing airspeed and continuing climb. It was about this time that I took control of the airplane since it appeared that my instruments were more reliable. I asked to level off at FL240 and upon reaching it; set approximately 80% N1 and told the first officer to get the relief pilot back in the cockpit immediately. Around this time; we began to receive multiple EICAS messages including rudder ratio; elevator asymmetry and stab trim. We also began smelling a very strong odor associated with st elmo's fire. The cabin crew informed me that they not only smelled the odor but the cabin was filled with haze. Shortly after the relief pilot returned to the cockpit; the EICAS messages began to disappear as well as the faulty indications that the first officer had with his pitot/static instruments. We also required a turn further to the north/northwest to avoid an area of precipitation which we were painting ahead. We declared an emergency and asked for vectors to divert back to the nearest airport; not knowing whether there had been any structural damage to the aircraft associated with the severe turbulence. We also were not convinced that the abnormal EICAS messages would remain out. We accomplished an overweight landing of about 240;000 pounds at the airport shortly thereafter uneventfully.

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Original NASA ASRS Text

Title: A B757 encountered severe turbulence during climb at FL220 which resulted in the temporary loss of the First Officer's flight instruments and the cabin crew reported an electrical odor/haze associated with St. Elmo's fire. The aircraft had cleared weather before this event but an emergency was declared and the flight diverted to a nearby airport.

Narrative: During climb out from the airport area we were vectored by ATC through an area of weather to the northeast of the airport. We were vectored between two moderate cells that were painting red on our radar. There was little turbulence associated with the weather. I thought the vectors turned out quite well. We emerged out of the weather on top for a few minutes and it looked as though it would be clear ahead with perhaps just some stratus above as there was no significant weather being painted on our radar other than just a bit of green. ATC informed us that there would be nothing worse than a bit of light chop as we continued our climb through approximately 16;000 FT. I informed our Number 1 Flight Attendant that they could begin their service but was told they would wait an additional 10 minutes before beginning; so they fortunately remained seated. A few minutes after clearing the significant weather that we had passed climbing through approximately FL220; we encountered about 7-10 seconds of violent up and down pulsating of the aircraft. Shortly after this encounter the autopilot and auto throttles were turned off. It was during this time; that the First Officer's airspeed indicated a significant loss of airspeed; perhaps going down to 240 KTS. His altimeter indicated that we were descending; but the Captain's altimeter indicated a steady climb and a speed of 300 KTS. If I recall; the First Officer began to chase the airspeed and altitude which resulted in a result opposite to which we needed as my airspeed and the standby airspeed both indicated increasing airspeed and continuing climb. It was about this time that I took control of the airplane since it appeared that my instruments were more reliable. I asked to level off at FL240 and upon reaching it; set approximately 80% N1 and told the First Officer to get the Relief Pilot back in the cockpit immediately. Around this time; we began to receive multiple EICAS messages including Rudder Ratio; Elevator Asymmetry and Stab Trim. We also began smelling a very strong odor associated with St Elmo's fire. The cabin crew informed me that they not only smelled the odor but the cabin was filled with haze. Shortly after the Relief Pilot returned to the cockpit; the EICAS messages began to disappear as well as the faulty indications that the First Officer had with his pitot/static instruments. We also required a turn further to the north/northwest to avoid an area of precipitation which we were painting ahead. We declared an emergency and asked for vectors to divert back to the nearest airport; not knowing whether there had been any structural damage to the aircraft associated with the severe turbulence. We also were not convinced that the abnormal EICAS messages would remain out. We accomplished an overweight landing of about 240;000 LBS at the airport shortly thereafter uneventfully.

Data retrieved from NASA's ASRS site as of April 2012 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.