A319 pilot reports aircraft abruptly climbing to capture the glideslope from below as the localizer ...

Narrative:

[We were] cleared for the ILS/DME [runway] 5R. Upon reaching the mex 249 degree turn-in radial; commenced descent to 8;800 ft and aircraft; flying on autopilot; initiated turn to final. As the aircraft turned to intercept the localizer; it also pitched up abruptly in order to capture the glideslope (we were one dot low). This resulted in a 'speed; speed; speed' low energy callout. I immediately disconnected the autopilot in order to temper the aggressive inputs; i.e. Decrease pitch; though my efforts were not timely or significant enough to avoid alpha floor (thrust automatically to toga). I performed the alpha floor recovery technique to regain control of the thrust and was still in a position to make a normal; stabilized approach. Landing was normal. We believe the additive effect of bank; pitch; and high density altitude came together to illicit this response and will fly this approach manually (hand fly) in the future. No adverse human factors to report.

Original NASA ASRS Text

Title: A319 pilot reports aircraft abruptly climbing to capture the glideslope from below as the LOC is intercepted. The autopilot is disengaged and the aircraft is pitched down; but not before Alpha floor is reached; resulting in TOGA thrust. Control is regained and a normal landing ensues.

Narrative: [We were] cleared for the ILS/DME [Runway] 5R. Upon reaching the MEX 249 degree turn-in radial; commenced descent to 8;800 FT and aircraft; flying on autopilot; initiated turn to final. As the aircraft turned to intercept the localizer; it also pitched up abruptly in order to capture the glideslope (we were one dot low). This resulted in a 'speed; speed; speed' low energy callout. I immediately disconnected the autopilot in order to temper the aggressive inputs; i.e. decrease pitch; though my efforts were not timely or significant enough to avoid Alpha floor (thrust automatically to TOGA). I performed the Alpha floor recovery technique to regain control of the thrust and was still in a position to make a normal; stabilized approach. Landing was normal. We believe the additive effect of bank; pitch; and high density altitude came together to illicit this response and will fly this approach manually (hand fly) in the future. No adverse human factors to report.

Data retrieved from NASA's ASRS site as of April 2012 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	947691
Time
Date	201105
Local Time Of Day	1201-1800
Place
Locale Reference	MMMX.Airport
State Reference	FO
Environment
Flight Conditions	VMC
Light	Daylight
Aircraft 1
Make Model Name	A319
Operating Under FAR Part	Part 121
Flight Phase	Initial Approach
Flight Plan	IFR
Component
Aircraft Component	Approach Coupler
Person 1
Function	Pilot Flying
Experience	Flight Crew Last 90 Days 120 Flight Crew Total 12000 Flight Crew Type 6000
Events
Anomaly	Aircraft Equipment Problem Less Severe Inflight Event / Encounter Loss Of Aircraft Control

A319 pilot reports aircraft abruptly climbing to capture the glideslope from below as the localizer is intercepted. The autopilot is disengaged and the aircraft is pitched down; but not before alpha floor is reached; resulting in toga thrust. Control is regained and a normal landing ensues.