Date: 201509
Local time of day: 1801-2400
Location: ZZZ.Airport, US
Flight conditions: VMC
Light: Night
Aircraft: B737 Undifferentiated or Other Model
Operator: Air Carrier
Operating under: Part 121
Flight plan: IFR
Mission: Passenger
Flight phase: Landing
ATC / advisory: Tower ZZZ
Reporter organization: Air Carrier
Reporter function: First Officer; Pilot Not Flying
Reporter qualification: Flight Crew Air Transport Pilot (ATP)
Second reporter function: Captain; Pilot Flying
Anomaly: Conflict Airborne Conflict; Deviation / Discrepancy - Procedural Published Material / Policy; Ground Event / Encounter Other / Unknown
Detector: Person Flight Crew; Person Passenger
When detected: In-flight
Result: General Physical Injury / Incapacitation; General Maintenance Action
Contributing factors: Weather; Human Factors; Aircraft
Primary problem: Human Factors

Narrative: On this leg; the captain was receiving a line check. We were unable to receive performance data through the FMC and dispatch was also having difficulty sending us the performance data we needed. Additionally; the winds would not uplink. We encountered a delay - not the best way to start a line check; creating some stress for the fairly new captain. All the situations were resolved successfully and the departure and enroute phases were normal. Considering we could not uplink descent winds we were a little concerned about descent planning since we had a strong tailwind. We carefully monitored our descent path with no issue. In the terminal area; we were given a heading to join final for a visual to the right with traffic converging on the left runway. We reported the traffic in sight. Approaching the final approach course we got a 'TA'. The captain shallowed the turn to join and we both acknowledged the traffic in sight. Joining final we got a 'descend RA'. We once again acknowledged the traffic and the captain instructed me to turn the transponder to 'TA' only. This distraction got us a little high on the glide path; but the captain corrected and we were soon back on glide path and made all the approach gates with plenty of room to spare. The remainder of the approach was normal. The captain; I believe; flared a little too high and retarded the throttles too abruptly causing the hard landing. There was no bounce and no apparent excessive pitch. We taxied to the gate normally.


Second narrative: It was a busy flight; a line check flight; starting with late flight papers; the box would not load some information; could not get take off numbers from Acars etc. Enroute busy listening to line check brief; including talking about risk of tail strike with this airplane and not to land with power on. Weather CBs just moved off as we approached. Got an RA on final; recovered and got back on approach profile. In the flare I perceived a wind shift but I was not fast enough with adding power to counter the loss of airspeed. I did not want to have a tail strike; so the flare was minimal and the landing was firm. Taxied to the gate where I was told 4 passengers claimed injuries from the firm landing. I was told today maintenance checked the aircraft and found no damage. Company provided paramedics for passengers; but I did not get answers regarding condition of passengers before I left on next flight; nor today when I asked.


Synopsis: A B737 flight crew reported a line check that does not get off to a good start due to factors beyond their control. In cruise the check airman discussed methods of landing this model B737 to avoid a tail strike. This discussion; a RA on final; and possible wind factors lead up to a hard landing which resulted in passengers reporting injury.