B787 captain reported the altitude alert set knob is too sensitive and easy to mis-set.

Attributes
ACN	1118877
Time
Date	201309
Local Time Of Day	1201-1800
Place
Locale Reference	ZZZ.ARTCC
State Reference	US
Environment
Flight Conditions	VMC
Light	Daylight
Aircraft 1
Make Model Name	B787 Dreamliner Undifferentiated or Other Model
Flight Phase	Climb
Route In Use	Direct
Flight Plan	IFR
Component
Aircraft Component	Altitude Alert
Person 1
Function	Pilot Flying Captain
Qualification	Flight Crew Air Transport Pilot (ATP) Flight Crew Flight Engineer
Experience	Flight Crew Last 90 Days 50 Flight Crew Total 30000 Flight Crew Type 50
Events
Anomaly	Aircraft Equipment Problem Less Severe Deviation - Altitude Overshoot Deviation - Procedural Clearance

Narrative:

Cleared to FL310; as we approached FL310 it was obvious the aircraft was not going to level. While leveling we overshot the altitude by several hundred feet. I called center and the controller said to continue climb to FL330. When I looked at the altitude window it was set at 31;800. We were warned in the simulator that this system was hyper-sensitive. If you set it and brush your finger on the knob as you pull off it will change the altitude. On IOE it was again brought up and the company has put out two bulletins regarding the altitude select window. Yet it still got me. The first officer I was flying with said he had seen this several times since he has been on the airplane. He demonstrated how you could push the knob in to 'recruise' the FMC and if you put the slightest side pressure on the knob it will change the selected altitude. I just finished 15 years flying the B777 and never once saw anything like this occur. I believe boeing has a serious design fault with this system that needs to be addressed.

Original NASA ASRS Text

Title: B787 Captain reported the altitude alert set knob is too sensitive and easy to mis-set.

Narrative: Cleared to FL310; as we approached FL310 it was obvious the aircraft was not going to level. While leveling we overshot the altitude by several hundred feet. I called Center and the Controller said to continue climb to FL330. When I looked at the altitude window it was set at 31;800. We were warned in the simulator that this system was hyper-sensitive. If you set it and brush your finger on the knob as you pull off it will change the altitude. On IOE it was again brought up and the company has put out two bulletins regarding the altitude select window. Yet it still got me. The First Officer I was flying with said he had seen this several times since he has been on the airplane. He demonstrated how you could push the knob in to 'recruise' the FMC and if you put the slightest side pressure on the knob it will change the selected altitude. I just finished 15 years flying the B777 and never once saw anything like this occur. I believe Boeing has a serious design fault with this system that needs to be addressed.

Data retrieved from NASA's ASRS site as of July 2013 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.