Narrative:

We were in the process of flying an uneventful approach at the end of an uneventful flight. The approach was the visual approach to runway 32 in ind. We were following an aircraft and another aircraft was about to depart and we assume that one of these aircraft; perhaps both; interfered with the glideslope signal. As is usual; we were backing up the visual approach with the ILS and on autopilot as well.when the interference occurred; it was sudden and surprising in intensity. I have seen this occur many times throughout the years; and without question this was the worst I've seen. As the glideslope deviated upward; the aircraft of course went with it and initiated a steep pitch attitude and almost full power. The first officer (first officer)was caught unaware as this was new to him; and in the moment's indecision; I assumed the controls and stabilized the aircraft. I was able to return to a stable configured flight path at about 1;100-1;200 ft; and decided to maintain controls for the remainder of the approach; as I didn't feel it appropriate to transfer controls at that point of the approach. We then landed without further incident.a check airman was on the jumpseat and was able to provide some added and informed insight to a discussion we all had upon reaching the parking point. The first officer seemed slightly shaken; and we veterans were surprised as well; at how quickly the aircraft reacted to a disrupted glideslope indication. The pitch and power inputs were drastic; personally; I'd like a download of the data to see just what it did. It was a vivid demonstration to the first officer of what this particular situation can do to a pilot in that you can have a pristine day that suddenly goes wrong. Without intervention; I'm not sure what state the aircraft would have achieved with the oscillation that followed. The downward pitch and excessive power input would probably have resulted in a potential CFIT threat.as well; indecision as to what action to take can create issues hazardous to a positive outcome of the flight. Absent a decision to correct the flight path or to call for a go-around; I needed to intervene; which provided a vivid and excellent teaching moment for the first officer who now has seen an authentic representation of how quickly scenarios can change in this environment. We decided to report this since we do believe it was an upset. There may be an issue with the glideslope itself and may need to be addressed by the airport authority as this scenario is easily repeated. The only way to get experience is to get experience. The first officer needed it; and now he has some more. Because I have some; we corrected it to an uneventful outcome.

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Original NASA ASRS Text

Title: Air carrier flight crew reported an interrupted glideslope signal at IND caused the aircraft to pitch up while on autopilot. The Captain took control from the First Officer and landed the aircraft.

Narrative: We were in the process of flying an uneventful approach at the end of an uneventful flight. The approach was the visual approach to runway 32 in IND. We were following an aircraft and another aircraft was about to depart and we assume that one of these aircraft; perhaps both; interfered with the glideslope signal. As is usual; we were backing up the visual approach with the ILS and on autopilot as well.When the interference occurred; it was sudden and surprising in intensity. I have seen this occur many times throughout the years; and without question this was the worst I've seen. As the glideslope deviated upward; the aircraft of course went with it and initiated a steep pitch attitude and almost full power. The first officer (FO)was caught unaware as this was new to him; and in the moment's indecision; I assumed the controls and stabilized the aircraft. I was able to return to a stable configured flight path at about 1;100-1;200 ft; and decided to maintain controls for the remainder of the approach; as I didn't feel it appropriate to transfer controls at that point of the approach. We then landed without further incident.A check airman was on the jumpseat and was able to provide some added and informed insight to a discussion we all had upon reaching the parking point. The FO seemed slightly shaken; and we veterans were surprised as well; at how quickly the aircraft reacted to a disrupted glideslope indication. The pitch and power inputs were drastic; personally; I'd like a download of the data to see just what it did. It was a vivid demonstration to the FO of what this particular situation can do to a pilot in that you can have a pristine day that suddenly goes wrong. Without intervention; I'm not sure what state the aircraft would have achieved with the oscillation that followed. The downward pitch and excessive power input would probably have resulted in a potential CFIT threat.As well; indecision as to what action to take can create issues hazardous to a positive outcome of the flight. Absent a decision to correct the flight path or to call for a go-around; I needed to intervene; which provided a vivid and excellent teaching moment for the FO who now has seen an authentic representation of how quickly scenarios can change in this environment. We decided to report this since we do believe it was an upset. There may be an issue with the glideslope itself and may need to be addressed by the airport authority as this scenario is easily repeated. The only way to get experience is to get experience. The FO needed it; and now he has some more. Because I have some; we corrected it to an uneventful outcome.

Data retrieved from NASA's ASRS site 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.