Flight Crew Multiengine; Flight Crew Instrument; Flight Crew Air Transport Pilot (ATP)
Troubleshooting
Aircraft Equipment Problem Less Severe; Deviation / Discrepancy - Procedural FAR; Deviation / Discrepancy - Procedural Published Material / Policy; Inflight Event / Encounter Other / Unknown
Aircraft Equipment Problem Dissipated; Flight Crew Overcame Equipment Problem
Environment - Non Weather Related
At about 40 NM east; northeast of IAH at 10;000 ft. we experienced what we thought to be a 5G event. We first became aware of it by the gear warning horn sounding and 3 red gear lights illuminating above the gear handle. It only lasted a couple of seconds; and then it flickered and sounded again. This time the Captain noticed his radio altimeter rapidly fluttering from around 1000 ft. to 1200 ft. This happened intermittently about 3 to4 times until it stopped. It all happened very quickly and I would say we hadn't traveled more than 5 miles from when it started to when it stopped. The warning horn was so loud and distracting it was hard to hear ATC; or ourselves for that matter.
10;000 ft. 40 miles northeast of airport; gear warning sounded [and the] radio altimeter read 1000 to 1100 ft. It cycled three times; then went away. Lasted about a minute [with] 5-10 seconds in between [alerts].
B737 flight crew reported a temporary 5G event during initial approach in which the gear warning horn and red gear handle lights alerted; accompanied by a radar altimeter fluctuation. The event repeated approximately three times during a short period but ceased for the remainder of flight.