Narrative:

On departure out of seattle, we temporarily climbed out of our assigned altitude of 9000 ft. The captain was flying (with the autoplt on). During the level off at our assigned altitude of 9000 ft the captain apparently did not pull the power back. The airspeed started to increase above 250 KTS. At about 265 KTS, the first officer said something about the increasing airspeed. The captain apparently did not hear, so I said something. At about 280 KTS (still level at 9000 ft), the captain realizing what was happening, punched off the autoplt and slowly brought the power back. Immediately the aircraft started to climb rapidly. At about 9300 ft, the first officer said, 'we're supposed to be at 9000 ft.' the captain then brought the power rapidly back to idle and pushed over the aircraft. The aircraft went up to about 9600 ft before it started down again. On the way down, through about 9300 ft, the ATC controller told us to climb to 15000 ft. There was 1 aircraft that had just passed over us at, I believe, 10000 ft. He was heading away from us during the time of this occurrence so there was no conflict, although less than proper IFR separation might have occurred. The captain was fairly new on this aircraft. His previous aircraft was much more automated than this one. He temporarily thought that this aircraft was going to do what his old one would. The captain was using the 'airspeed hold' and altitude capture feature of the autoplt. When the aircraft captured its altitude at 9000 ft, the autoplt kicked off the airspeed hold (which it is supposed to do) and since the throttles were at climb power the airspeed rapidly built up. (The captain's old aircraft had automatic throttles which automatically brought the power back.) with the airspeed increasing rapidly, the autoplt did not have time to trim for this new airspeed. So when the captain punched the autoplt off, the aircraft was not in trim and started an immediate climb. This all happened in a matter of a few seconds. We were all surprised at how fast the aircraft started to climb before we noticed it. After discussing the situation later, the first officer said he hesitated on saying something to the captain right away, because he didn't want to bug him and he thought he would catch it himself. In retrospect, both the first officer and I should have said something earlier. Another factor that could have contributed to this situation is the fact that our company has many different configns of this aircraft. Some autoplts have the altitude capture feature, and some don't. Some have an airspeed hold feature, and some don't. This, together with someone who was used to an even more automated system, seems to have contributed to this situation.

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Original NASA ASRS Text

Title: ACR LGT SPD DEV AT 9000 FT AND ALTDEV EXCURSION FROM CLRNC ALT.

Narrative: ON DEP OUT OF SEATTLE, WE TEMPORARILY CLBED OUT OF OUR ASSIGNED ALT OF 9000 FT. THE CAPT WAS FLYING (WITH THE AUTOPLT ON). DURING THE LEVEL OFF AT OUR ASSIGNED ALT OF 9000 FT THE CAPT APPARENTLY DID NOT PULL THE PWR BACK. THE AIRSPD STARTED TO INCREASE ABOVE 250 KTS. AT ABOUT 265 KTS, THE FO SAID SOMETHING ABOUT THE INCREASING AIRSPD. THE CAPT APPARENTLY DID NOT HEAR, SO I SAID SOMETHING. AT ABOUT 280 KTS (STILL LEVEL AT 9000 FT), THE CAPT REALIZING WHAT WAS HAPPENING, PUNCHED OFF THE AUTOPLT AND SLOWLY BROUGHT THE PWR BACK. IMMEDIATELY THE ACFT STARTED TO CLB RAPIDLY. AT ABOUT 9300 FT, THE FO SAID, 'WE'RE SUPPOSED TO BE AT 9000 FT.' THE CAPT THEN BROUGHT THE PWR RAPIDLY BACK TO IDLE AND PUSHED OVER THE ACFT. THE ACFT WENT UP TO ABOUT 9600 FT BEFORE IT STARTED DOWN AGAIN. ON THE WAY DOWN, THROUGH ABOUT 9300 FT, THE ATC CTLR TOLD US TO CLB TO 15000 FT. THERE WAS 1 ACFT THAT HAD JUST PASSED OVER US AT, I BELIEVE, 10000 FT. HE WAS HDG AWAY FROM US DURING THE TIME OF THIS OCCURRENCE SO THERE WAS NO CONFLICT, ALTHOUGH LESS THAN PROPER IFR SEPARATION MIGHT HAVE OCCURRED. THE CAPT WAS FAIRLY NEW ON THIS ACFT. HIS PREVIOUS ACFT WAS MUCH MORE AUTOMATED THAN THIS ONE. HE TEMPORARILY THOUGHT THAT THIS ACFT WAS GOING TO DO WHAT HIS OLD ONE WOULD. THE CAPT WAS USING THE 'AIRSPD HOLD' AND ALT CAPTURE FEATURE OF THE AUTOPLT. WHEN THE ACFT CAPTURED ITS ALT AT 9000 FT, THE AUTOPLT KICKED OFF THE AIRSPD HOLD (WHICH IT IS SUPPOSED TO DO) AND SINCE THE THROTTLES WERE AT CLB PWR THE AIRSPD RAPIDLY BUILT UP. (THE CAPT'S OLD ACFT HAD AUTO THROTTLES WHICH AUTOMATICALLY BROUGHT THE PWR BACK.) WITH THE AIRSPD INCREASING RAPIDLY, THE AUTOPLT DID NOT HAVE TIME TO TRIM FOR THIS NEW AIRSPD. SO WHEN THE CAPT PUNCHED THE AUTOPLT OFF, THE ACFT WAS NOT IN TRIM AND STARTED AN IMMEDIATE CLB. THIS ALL HAPPENED IN A MATTER OF A FEW SECONDS. WE WERE ALL SURPRISED AT HOW FAST THE ACFT STARTED TO CLB BEFORE WE NOTICED IT. AFTER DISCUSSING THE SITUATION LATER, THE FO SAID HE HESITATED ON SAYING SOMETHING TO THE CAPT RIGHT AWAY, BECAUSE HE DIDN'T WANT TO BUG HIM AND HE THOUGHT HE WOULD CATCH IT HIMSELF. IN RETROSPECT, BOTH THE FO AND I SHOULD HAVE SAID SOMETHING EARLIER. ANOTHER FACTOR THAT COULD HAVE CONTRIBUTED TO THIS SITUATION IS THE FACT THAT OUR COMPANY HAS MANY DIFFERENT CONFIGNS OF THIS ACFT. SOME AUTOPLTS HAVE THE ALT CAPTURE FEATURE, AND SOME DON'T. SOME HAVE AN AIRSPD HOLD FEATURE, AND SOME DON'T. THIS, TOGETHER WITH SOMEONE WHO WAS USED TO AN EVEN MORE AUTOMATED SYS, SEEMS TO HAVE CONTRIBUTED TO THIS SITUATION.

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.