Airbus flight crew reported during approach into MIA the aircraft unexpectedly pitched down; leveled off; and began descending again. Captain disengaged autopilot; regained altitude; and continued to landing. Reportedly; this is a known issue on the line.
Synopsis
Airbus flight crew reported during approach into MIA the aircraft unexpectedly pitched down; leveled off; and began descending again. Captain disengaged autopilot; regained altitude; and continued to landing. Reportedly; this is a known issue on the line.
Narrative
We were cleared for the RNAV(GPS) 26R approach into MIA with VFR conditions. I set up the approach and the FO (First Officer) verified all the information. We were cleared for the approach and armed it and saw FINALAPP with the autopilot engaged. The plane was descending on the profile until near the shoreline when the plane nosed over dramatically; leveled off and started descending again. As I [was] turning off the autopilot and leveling off; the Tower told us to check our altitude immediately. We were approximately 80 feet low when we turned off the autopilot and climbed back up to 1;500 to cross JODAX at 1;500. After JODAX I re-engaged the autopilot and the flight path remained on track and we landed without further incident. If this was IMC conditions and the crew did not notice the descent; the plane would have been on a path to the high rise condos.I spoke with another Airbus Captain and he said this is known issue on the line. I am not sure what caused this and I followed up with a Check Airman who also wasn't sure what would have caused this.Suggestions - Close monitoring of the autopilot on this approach. Maybe ask pilots if they have encountered this before.
Second reporter narrative
On approach (VMC) descending to altitude to cross FAF (FINAL APP displayed on FMA) the aircraft started a fairly rapid descent. Captain disconnected autopilot and arrested rate of descent. At the same time ATC queried us to check altitude. Lowest published altitude was maintained until crossing FAF and rest of approach/landing was normal. Aircraft seemed to be on a normal descent profile. Automation seemed to be a factor. Not sure if an anomaly on the approach itself. But; disconnecting the autopilot and executing (autopilot off/arresting rate of descent) worked.
NASA callback
Reporter stated he is unsure of the root cause of this event.
Source: NASA Aviation Safety Reporting System (public domain). Reports are voluntary submissions and are not verified by NASA.