A300
Flight Crew Air Transport Pilot (ATP)
Flight Crew Last 90 Days 30; Flight Crew Total 10000; Flight Crew Type 4000
Situational Awareness
ATC Issue All Types; Deviation / Discrepancy - Procedural Published Material / Policy; Inflight Event / Encounter CFTT / CFIT; Inflight Event / Encounter Unstabilized Approach
Flight Crew Became Reoriented; Flight Crew Returned To Clearance
Environment - Non Weather Related; Human Factors; Procedure
We crossed the HAMMY glide slope intercept point at 3000 MSL and started down the glide path. The altitude checked and everything seemed normal. Almost immediately the aircraft started oscillating in pitch in response to the erratic glide slope. I made a comment to my First Officer that he was going to have to kick the autopilot off and hand fly the aircraft as the autopilot was not doing an adequate job. FO disconnected the autopilot and began hand flying. Everything at first appeared normal. Finally; he made the comment to me that 'something was not right; it was taking almost 1500 FPM to stay on the glide path.' This is about the point we were coming though the broken layer at around 1200 AGL. He had just established visual contact with the ground and the runway. I told [him] I agreed with him and thought he should level off as it appeared we were low for our distance from the airport. Immediately after I made this comment the Tower Controller informed us he had a low altitude alert on our aircraft and to check our altitude. We leveled off and visually captured the PAPI. From there we flew the PAPI to the runway. From that point through the landing the glide slope indicator showed one and a half dots high. It is worth noting at the time of this incident runway 18L was closed and Orlando was using runway 18R for both takeoffs and landings. There was a solid line of aircraft holding short of the runway waiting to takeoff. We let the Tower know what had occurred and confirmed with them after landing that the ILS signal had not been protected during our landing.
A300 Captain reported receiving a low altitude alert from the Tower on approach to MCO when taxiing aircraft probably interfered with the glideslope signal.