B737-800
Training / Qualification; Situational Awareness
Aircraft Equipment Problem Less Severe; Deviation - Altitude Overshoot; Deviation - Altitude Excursion From Assigned Altitude; Deviation / Discrepancy - Procedural Published Material / Policy
Flight Crew Returned To Clearance; Flight Crew Took Evasive Action
Aircraft; Procedure
At approximately 3 miles outside of PAYMI; at 3;000 FT; on a vector to intercept final; and with clearance for the ILS 13 approach; I selected approach mode with the autopilot engaged. The glideslope indicator was passing through centered to the below glideslope indication; so the aircraft began a strong climb to 'catch' the glideslope. I disengaged the autopilot and began a smooth pushover. I topped out at 3;300 before correcting back to 3;000 prior to PAYMI.Do not engage approach mode prior to localizer capture. Be more situationally aware of where the glideslope is and where capture should occur.
Fast fingered Captain should wait until we are established on the LOC course inbound and at PAYMI before engaging APP mode for ILS.
Prior to intercepting the LGA Runway 13 ILS localizer; a B737-800 Captain selected the APP mode and as the glideslope indicatored passed through centered climbing; the aircraft unexpectely pitched.