A ce-560 captain reported the autopilot failed to capture the teb ruudy 4 wentz constraint so it was...

Narrative:

On ruudy 4 departure; sometime after flap retraction; I called for autopilot engagement. I noted indications on the pfd that the autopilot was engaged. I then selected vertical speed (vs) and decreased the rate of climb. The pfd switched from vs to asel as we approached 1;500 ft MSL. I then noted that the vertical speed and pitch drastically increased. I disconnected the autopilot and stopped the climb in a positive manner with considerations for passenger comfort; and returned the aircraft to 1;500 ft. The maximum altitude was 1;640 ft (1;500 mandatory crossing altitude at wentz). There was no comment from new york departure about the deviation. The autopilot functioned normally for the remainder of the flight; except for a tendency to not level off smoothly when climbing at rates great than 1;000 FPM. With the time compression on the initial stages of the ruudy 4 departure; I should have called for the autopilot engagement earlier. Most pilots engage their own autopilot; rather than call for the pilot not flying to engage it. This may have caught the pilot not flying off guard and delayed engagement; as he was busy with radio calls.

Original NASA ASRS Text

Title: A CE-560 Captain reported the autopilot failed to capture the TEB RUUDY 4 WENTZ constraint so it was disconnected and the aircraft returned to 1;500 FT.

Narrative: On RUUDY 4 departure; sometime after flap retraction; I called for autopilot engagement. I noted indications on the PFD that the autopilot was engaged. I then selected Vertical Speed (VS) and decreased the rate of climb. The PFD switched from VS to ASEL as we approached 1;500 FT MSL. I then noted that the vertical speed and pitch drastically increased. I disconnected the autopilot and stopped the climb in a positive manner with considerations for passenger comfort; and returned the aircraft to 1;500 FT. The maximum altitude was 1;640 FT (1;500 mandatory crossing altitude at WENTZ). There was no comment from New York Departure about the deviation. The autopilot functioned normally for the remainder of the flight; except for a tendency to not level off smoothly when climbing at rates great than 1;000 FPM. With the time compression on the initial stages of the RUUDY 4 departure; I should have called for the autopilot engagement earlier. Most pilots engage their own autopilot; rather than call for the pilot not flying to engage it. This may have caught the pilot not flying off guard and delayed engagement; as he was busy with radio calls.

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.

Attributes
ACN	1033912
Time
Date	201208
Local Time Of Day	1201-1800
Place
Locale Reference	TEB.Airport
State Reference	NJ
Environment
Flight Conditions	VMC
Light	Daylight
Aircraft 1
Make Model Name	Citation V/Ultra/Encore (C560)
Operating Under FAR Part	Part 91
Flight Phase	Initial Climb
Route In Use	SID RUUDY 4
Flight Plan	IFR
Component
Aircraft Component	Altitude Hold/Capture
Person 1
Function	Pilot Flying Captain
Qualification	Flight Crew Air Transport Pilot (ATP)
Events
Anomaly	Deviation - Altitude Overshoot Deviation - Procedural Published Material / Policy Deviation - Procedural Clearance

A ce-560 captain reported the autopilot failed to capture the teb ruudy 4 wentz constraint so it was disconnected and the aircraft returned to 1;500 ft.