B737-800
Flight Crew Multiengine; Flight Crew Air Transport Pilot (ATP); Flight Crew Instrument
Situational Awareness
Deviation / Discrepancy - Procedural Published Material / Policy; Ground Event / Encounter Other / Unknown
General None Reported / Taken
Airport; ATC Equipment / Nav Facility / Buildings; Human Factors; Weather
We flew the RNAV Y Runway 20 to Guatemala City. The weather was right above minimums. We briefed the approach thoroughly; including possible go around; diversion; and landing analysis (both wet and dry). We also noted the company notes regarding the use of visual references when descending below mins. Upon check in with the Tower; they reported that there was a light rain falling; so we switched to MAX braking. We broke out at about 100 ft. above minimums; and saw the approach lights and the runway environment. The approach lighting was turned up to high and was somewhat disorienting. I noticed the PAPI were all red. I alerted the Captain to this by saying 'You're low'. The Captain later mentioned that the bright lights made it so he couldn't see the HUD very well. I also glanced at his PFD and he was right on the RNAV glide path. As we came over the approach end and the lights disappeared; the darkness of the runway was again disorienting (there are no centerline or touchdown lights in the runway. The only lighting is the runway edge lights); which made it hard to judge the height above the ground. We touched down very firm and both felt startled because I don't think either of us saw the firm landing coming. Weather at mins; low visibility; approach lights on high; glare on the HUD; lack of runway lighting and a down-sloping runway with a cliff at the end all contributed to the firm landing. Check the intensity of the approach lighting system with Tower; turn the HUD brightness up higher; and perhaps anticipated the down-sloping runway better.
B737-800 First Officer reported firm landing.