Date: 201810
Local time of day: 1801-2400
Location: DEN.Airport, CO
Flight conditions: VMC
Aircraft: B737-800
Operator: Air Carrier
Operating under: Part 121
Flight plan: IFR
Flight phase: Initial Approach
Airspace: Class B DEN
ATC / advisory: Tower DEN
Reporter organization: Air Carrier
Reporter function: Pilot Flying; Captain
Reporter qualification: Flight Crew Multiengine; Flight Crew Air Transport Pilot (ATP); Flight Crew Instrument
Human factors: Situational Awareness
Anomaly: Deviation / Discrepancy - Procedural Published Material / Policy; Inflight Event / Encounter Unstabilized Approach
Detector: Person Flight Crew
When detected: In-flight
Result: General None Reported / Taken
Contributing factors: Human Factors; Aircraft
Primary problem: Human Factors

Narrative: The purpose of this [report] is to explain a situation where I unintentionally used a high rate of descent to recapture a glide path landing in DEN in a 737 MAX. I have flown the MAX a few times [before] but this was the first time I've flown it in a high density altitude airport. The landing was uneventful and I felt like I was in control the entire final approach but the rate of descent was higher than I anticipated or normally use due to my hesitancy to quickly revert from reliance on technology to visual approach procedures. I understand the emphasis on visual approaches in training and safety. After an uneventful flight to DEN we were given a left downwind turn to base for DEN runway 16L outside of LEETS at 7000 feet. It was a clear night so I accepted the visual when offered and slowed appropriately for the final decent. To increase my familiarity of the MAX; prior to top of descent; I briefed and intended to engage ARM III below 5000 feet AGL and set up the HUD to do so. As we neared LEETS I pushed the Approach ARM button (with 7000 feet in the MCP) but my attention was outside and on the flight display system when I made a rookie mistake. I didn't notice that the Approach mode did not arm. I have flown the 737 MAX a few times and was familiar with; what I believe to be; slightly different descent characteristics. Also; I armed the speed brakes but apparently when I did so the handle was slightly past the detent. I don't know if the ARM switch wouldn't engage as a result of this or not? Also I don't know if the Landing Attitude Modifier behaves differently due to the speed brake handle not precisely set in detent? Of course since I had 7000 feet in the MCP as we flew past LEETS I lost vertical path display and in the moment(s) it took to evaluate what was happening; I got high on path. The vertical guidance displays were now unusable so I abandoned the idea of the CAT III practice and adjusted to a high rate of descent to visually get on the PAPI. Since DEN is 5434 feet I rationalized that a higher descent rate was appropriate due to the high density altitude and called 'stable' at 1000 feet with a 1200 feet rate of descent but correcting. When I adjusted the throttles; the speed brake green light went to amber and the FO (First Officer) quickly and correctly armed the speed brake. I didn't get enough power in soon enough and ended up getting three reds on the PAPI and a 'Glide Slope' announcement to which I adjusted up to regain path. I continued to an uneventful landing. As a result of this situation which happened very quickly; I will 1) recommit to confirming buttons arm when pushed; 2) recommit to confirming the speed brake handle is fully in the arm detent (in addition to the green arm light) 3) react more swiftly to visual methods (or go around) when appropriate when displays don't appear as expected and 4) continue to ensure stabilized approaches or go around as necessary.




Synopsis: B737 MAX Captain reported an unstabilized approach into DEN due to human factors and aircraft familiarization.