Date: 201703
Local time of day: 1801-2400
Location: ZZZ.Airport, US
Flight conditions: Marginal
Weather elements / visibility: Turbulence
Aircraft: A300
Operator: Air Carrier
Operating under: Part 121
Flight plan: IFR
Flight phase: Landing
ATC / advisory: Tower ZZZ
Aircraft component: Radio Altimeter
Component problem: Malfunctioning
Reporter organization: Air Carrier
Reporter function: Pilot Flying; Captain
Reporter qualification: Flight Crew Air Transport Pilot (ATP)
Human factors: Situational Awareness
Second reporter function: Pilot Not Flying; First Officer
Anomaly: Aircraft Equipment Problem Less Severe; Ground Event / Encounter Other / Unknown
Detector: Person Flight Crew
When detected: In-flight
Result: Aircraft Aircraft Damaged; General Maintenance Action
Contributing factors: Human Factors; Aircraft
Primary problem: Human Factors

Narrative: Flew an ILS to runway XY. The set speed was hook plus 8 for the wind additive. Tower called winds at 16 but no gust. All felt and appeared normal on the approach. At 30 feet I de-crabbed and started to drop the right wing. The landing picture seemed normal and at about 20 feet it started to feel like the 'bottom was dropping out'. I added a little power and the aircraft touched down very firmly. The aircraft didn't bounce and the rollout was normal. I wasn't sure if I it was a hard landing so I wrote up in the aircraft forms and debriefed Maintenance (MX) that I had a possible hard landing. I walked around the aircraft and MX inspected it with no problems observed. This landing has bothered me since it occurred. I didn't observe anything out of the ordinary and I didn't see it coming. In the debrief with the first officer; he stated he didn't see anything out of the ordinary. The next morning I asked him if he remembered the cadence of the radio altimeter and neither could remember. I received an email that it was a hard landing and that Airbus is recommending a gear change.The only conclusion I can reach is human error. I didn't see anything out of the ordinary developing. Approaching the touchdown I felt the landing might be firm but acceptable. While it was a long day with a night day swap the day prior; I didn't feel overly tired or fatigued. A high sink rate must have developed and I didn't see it or correct.I missed something with this landing. Whether the cause was sink rate; speed control; wind shift or gust. I still can't explain why this happened. I am confident in my abilities to capture and correct for changing conditions. My crosscheck missed a developing situation and I failed to recognize or correct the situation.


Second narrative: Passing 1000 feet AGL; with the runway in sight; the radio altimeter 1000 feet call was garbled. Passing the 500 feet call was even less understandable. I don't recall hearing the 100; 50; 40; 30; 20 or 10 call outs. It was a normal approach prior to touchdown. At around 20 feet it felt like we picked up a little more sink rate. The Captain added some power and we touched down firmly.I believe that the lack of radio altimeter call outs contributed to the hard landing. The amount of flare is usually based on the radio altimeter cadence. In this instance there was no call outs. This radio altimeter malfunction is something I have never experienced or heard of. Incorporating this malfunction into simulator training would bring this instance into light.


Synopsis: A300 flight crew reported a hard landing resulted in a recommendation from Airbus to replace the landing gear. Radio altimeter reportedly provided no callouts during short final; which was cited as a factor in the hard landing.