Narrative:

We were cleared to climb and maintain FL270. During climb, we experienced moderate turbulence. I requested turbulence reports and was told that all altitudes from FL270 up to FL370 were reporting moderate turbulence. I then requested a clearance to a lower altitude. We were reclred to FL240. We received the new clearance as we were climbing through 26600'. I reset the altitude alert and reiterated to the first officer, who was flying the aircraft, that the new clearance was FL240. He acknowledged. I began turning on the engine anti-ice as the temperature had dropped and we were now in the clouds. I checked the altitude and we were climbing through 27200'. I said, 'do not go any higher, begin a descent now.' I noticed that the first officer had selected IAS on the MCP. He had not reduced the power and the autoplt was attempting to maintain IAS with full climb power. I realized that the climb was going to continue, so I selected altitude hold. The first officer then selected vertical speed and disconnected the autoplt. He began to fly the flight director, which was calling for +3800 FPM climb. I then pushed very aggressively on the yoke and the climb peaked at 27550'. I continued to push until we were below 27000' and descending. I set up the flight director on vertical speed and -2500 FPM and gave the aircraft back to the first officer. I am confident that we did not create a traffic conflict. ATC did not mention the altitude deviation and no traffic was visible on TCAS. Contributing factors: WX, unfamiliar route, turbulence, inadequate training, overdependence on automation, poor autoplt design. The WX factors here are obvious. Clouds, potential icing and turbulence. All of the factors demand attention. Inadequate training is obvious description of the chaos that occurred during the few seconds that this event transpired. The reasons for the inadequate training go much deeper. There are problems with training devices that have programming and logic discrepancies. Many training programs do not address adequately the real time environment. Instrs are poorly trained and have little or no insight into the education process. There are assumptions that because of certain aviation backgrounds, some individuals 'already know that,' therefore certain aspects of training are deleted or glossed over. Overdependence on automation is self-explanatory. This aspect of the problem is beginning to be addressed by our training department. Poor autoplt design is a major contributing factor to incidents ot this kind. I strongly object to any automation that is user unfriendly. The IAS mode of the aircraft is very definitely in that category. The IAS button will attempt, under most circumstances, to maintain indicated airspeed while ignoring all other parameters such as altitude. I am constantly preventing altitude deviations by first officer's who use this mode of the autoplt. I would simply not allow its use, but I would then have to personally retrain every first officer that I fly with. Our flight training department emphasizes the use of the IAS mode. I never use the IAS mode myself because an altitude deviation can easily happen with even the slightest mismanagement.

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Original NASA ASRS Text

Title: FO, PF, SELECTED IAS HOLD VERSUS VS RESULTED IN OVERSHOOTING ALT 550'.

Narrative: WE WERE CLRED TO CLB AND MAINTAIN FL270. DURING CLB, WE EXPERIENCED MODERATE TURB. I REQUESTED TURB RPTS AND WAS TOLD THAT ALL ALTS FROM FL270 UP TO FL370 WERE RPTING MODERATE TURB. I THEN REQUESTED A CLRNC TO A LOWER ALT. WE WERE RECLRED TO FL240. WE RECEIVED THE NEW CLRNC AS WE WERE CLBING THROUGH 26600'. I RESET THE ALT ALERT AND REITERATED TO THE F/O, WHO WAS FLYING THE ACFT, THAT THE NEW CLRNC WAS FL240. HE ACKNOWLEDGED. I BEGAN TURNING ON THE ENG ANTI-ICE AS THE TEMP HAD DROPPED AND WE WERE NOW IN THE CLOUDS. I CHKED THE ALT AND WE WERE CLBING THROUGH 27200'. I SAID, 'DO NOT GO ANY HIGHER, BEGIN A DSNT NOW.' I NOTICED THAT THE F/O HAD SELECTED IAS ON THE MCP. HE HAD NOT REDUCED THE PWR AND THE AUTOPLT WAS ATTEMPTING TO MAINTAIN IAS WITH FULL CLB PWR. I REALIZED THAT THE CLB WAS GOING TO CONTINUE, SO I SELECTED ALT HOLD. THE F/O THEN SELECTED VERT SPD AND DISCONNECTED THE AUTOPLT. HE BEGAN TO FLY THE FLT DIRECTOR, WHICH WAS CALLING FOR +3800 FPM CLB. I THEN PUSHED VERY AGGRESSIVELY ON THE YOKE AND THE CLB PEAKED AT 27550'. I CONTINUED TO PUSH UNTIL WE WERE BELOW 27000' AND DSNDING. I SET UP THE FLT DIRECTOR ON VERT SPD AND -2500 FPM AND GAVE THE ACFT BACK TO THE F/O. I AM CONFIDENT THAT WE DID NOT CREATE A TFC CONFLICT. ATC DID NOT MENTION THE ALT DEVIATION AND NO TFC WAS VISIBLE ON TCAS. CONTRIBUTING FACTORS: WX, UNFAMILIAR RTE, TURB, INADEQUATE TRNING, OVERDEPENDENCE ON AUTOMATION, POOR AUTOPLT DESIGN. THE WX FACTORS HERE ARE OBVIOUS. CLOUDS, POTENTIAL ICING AND TURB. ALL OF THE FACTORS DEMAND ATTN. INADEQUATE TRNING IS OBVIOUS DESCRIPTION OF THE CHAOS THAT OCCURRED DURING THE FEW SECS THAT THIS EVENT TRANSPIRED. THE REASONS FOR THE INADEQUATE TRNING GO MUCH DEEPER. THERE ARE PROBS WITH TRNING DEVICES THAT HAVE PROGRAMMING AND LOGIC DISCREPANCIES. MANY TRNING PROGRAMS DO NOT ADDRESS ADEQUATELY THE REAL TIME ENVIRONMENT. INSTRS ARE POORLY TRAINED AND HAVE LITTLE OR NO INSIGHT INTO THE EDUCATION PROCESS. THERE ARE ASSUMPTIONS THAT BECAUSE OF CERTAIN AVIATION BACKGROUNDS, SOME INDIVIDUALS 'ALREADY KNOW THAT,' THEREFORE CERTAIN ASPECTS OF TRNING ARE DELETED OR GLOSSED OVER. OVERDEPENDENCE ON AUTOMATION IS SELF-EXPLANATORY. THIS ASPECT OF THE PROB IS BEGINNING TO BE ADDRESSED BY OUR TRNING DEPT. POOR AUTOPLT DESIGN IS A MAJOR CONTRIBUTING FACTOR TO INCIDENTS OT THIS KIND. I STRONGLY OBJECT TO ANY AUTOMATION THAT IS USER UNFRIENDLY. THE IAS MODE OF THE ACFT IS VERY DEFINITELY IN THAT CATEGORY. THE IAS BUTTON WILL ATTEMPT, UNDER MOST CIRCUMSTANCES, TO MAINTAIN INDICATED AIRSPD WHILE IGNORING ALL OTHER PARAMETERS SUCH AS ALT. I AM CONSTANTLY PREVENTING ALT DEVIATIONS BY F/O'S WHO USE THIS MODE OF THE AUTOPLT. I WOULD SIMPLY NOT ALLOW ITS USE, BUT I WOULD THEN HAVE TO PERSONALLY RETRAIN EVERY F/O THAT I FLY WITH. OUR FLT TRNING DEPT EMPHASIZES THE USE OF THE IAS MODE. I NEVER USE THE IAS MODE MYSELF BECAUSE AN ALT DEVIATION CAN EASILY HAPPEN WITH EVEN THE SLIGHTEST MISMANAGEMENT.

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.