Date: 202011
Local time of day: 0001-0600
Location: OKC.Airport, OK
Aircraft: Commercial Fixed Wing
Operator: Air Carrier
Operating under: Part 121
Flight plan: IFR
Mission: Passenger
Flight phase: Initial Approach
Airspace: Class C OKC
ATC / advisory: Tower OKC
Reporter organization: Air Carrier
Reporter function: Captain; Pilot Flying
Reporter qualification: Flight Crew Instrument; Flight Crew Multiengine; Flight Crew Air Transport Pilot (ATP)
Human factors: Situational Awareness
Second reporter function: First Officer; Pilot Not Flying
Anomaly: Deviation - Altitude Excursion From Assigned Altitude; Deviation / Discrepancy - Procedural Published Material / Policy; Deviation / Discrepancy - Procedural Clearance; Inflight Event / Encounter CFTT / CFIT
Detector: Automation Aircraft Terrain Warning
When detected: In-flight
Result: Flight Crew Took Evasive Action
Contributing factors: Human Factors
Primary problem: Human Factors

Narrative: During vectors into OKC from the east; the Approach Controller assigned us Runway 17R differently from the one we had setup (17L). After re-configuring for the ILS 17R; I asked the Pilot Monitoring to brief the approach so I can concentrate on flying (Approximately 14;000 feet MSL and descending to 4;000 feet). During the brief a bright shining white light; like a spotlight shined at us; caught our attention and cause a distraction. We still conducted the briefing; including the highest elevation figure. As I kept flying I was paying attention if the light shined us again; in the event it was a laser that needed to be reported. I had the terrain page setup from the previous briefing and both pilots were aware of the obstacle northeast of the airport (Antenna 2758 feet MSL). After the briefing was complete; we were given a vector (a 90 degree angle) for the approach within a close proximity of the Final Approach Fix (minimum altitude at FAF 3;000 feet MSL). This vector would have flown us south of the obstacle depicted in the plan view section of the approach chart. Approximately 18NM from the airport the Approach Controller queried the visual contact of the airport. Pilot Monitoring told me he had contact with it and after I picked it up in sight I asked to call for it if he still had it. At that point the Approach Controller cleared us for the visual approach for [Runway] 17R. Slightly after; the Approach Controller notified us of traffic on the approach to the parallel runway. Both pilots were trying to ID the traffic since it was below our altitude and we had to cross his approach path. We seemed clear of the traffic; but a strong wind from the south was drifting us north which cause a concern for us due to the known obstacle. The aircraft was just approaching 4;000 feet of altitude and started to level off; when I set 3;000n in the Altitude Select box. The aircraft transitioned into a shallow descent instead of holding 4;000 since it wasn't fully captured. While having a discussion about the wind I adjusted my heading and kept the descent to 3;000 feet so we could be close to level and slow when we intercepted the course outside of the FAF. Around 3500 feet we both remembered the obstacles when we saw its lights ahead and below us. I already started a transition into a climb when the Pilot Monitoring verbally reminded me of the obstacles. During the climb we got a 'Caution Obstacle'; due to the projected descent; which was removed shortly since we were already compensating. We were 500 to 700 feet above the highest obstacle. The obstacle represented on the MFD was not the highest elevation figure on the IAP chart. This depicted obstacle was part of another group of towers not depicted on the chart but they can be seen on the VFR chart in the Jeppesen app. Since it was a visual approach; I had focused on maintaining the airport inside; and started to descend and slow down so we could be on a good position for the stable approach. Following the event; we landed with no issues and had a discussion at the gate on how we could have mitigated our error. We were below the MSA and had loss awareness of the obstacles due to other distractions and the tight vector to the approach with the visual approach. Several factors played key roles for the loss of situational awareness that led us to be at a lower altitude for our location. Flags:-A night Visual approach into an airport were an obstacle is a threat.-A night Visual approach to an airport were the elevation of the airport is higher than we are normally used to.-An arrival consisting of an extended base into a visual approach rather than a downwind arrival.-The change of runway that led to a new setup and briefing.-The distractions caused by the wind-drift; traffic; and the bright light.-The tight vector given and accepted for the original approach. Our error was the premature descent to 3000 feet with the goal of not being high once we intercept the final course with short distance to the final fix. Although the setup for the approach included the awareness of terrain and using the terrain displayed as an aid; we should have use TEM to establish a plan to avoid the premature descent. A briefed plan of using the last assigned altitude of 4;000 feet until intercepting would have avoided this. During the approach brief; I should have asked my Pilot Monitoring to intervene in the event I set a lower altitude while maneuvering for the visual (mitigation plan in the vent of losing SA). I realized that our briefings cover informational items that could be threats but we should discuss mitigating plans for them. Other actions that could have been taken are: 1) denying the visual at night due to the obstacle; 2) requesting a vector for the visual; and 3) querying if a lower altitude was needed which would have led the Controller to keep us at 4;000 feet.


Second narrative: I was Pilot Monitoring. Approximately 20min out we were giving the option to change our landings intentions from [Runway] 17L to 17R which we took. Captain asked me if I could brief the approach which I did and then we performed the runway change items from the checklist. During this briefing moment we both noticed a bright light from about a 12 o'clock position which caught our attention. Captain was aware of the obstacles to the northeast of the airport (antennas) and turned on the terrain. At approximately 18 miles out we were asked if we had the airport in sight. We both saw it and were cleared for the visual approach Runway 17R. Winds were out of the south at approximately 26kt pushing us to the north since we were coming from the east. We were at 4;000 ft. and began a gradual descent. ATC advised us of traffic at 11 o'clock landing on the parallel runway. Looking for the traffic we began to noticed the red lights of the obstacles (towers) on the northeast of the airport. I pointed them out as [did] the Captain. The altitude window was set for 3;000 ft. we were currently at 3;400 ft. Captain turned off the autopilot and began a climb. As we were climbing we received a Caution for the obstacle but it cleared quickly since the Captain had already began the climb. Once cleared we continue to intercept the final approach course and perform a normal landing. We both had a long discussion after the flight and both agreed that we should had mitigated this by simply staying at 4;000ft when cleared for the visual approach since we knew about the MSA which is 3;800 ft. Also the parallel traffic played a role on this since we started looking for it due to it being in our path for intercepting the final approach course of [Runway] 17R. As a Pilot Monitoring I should had advised the Captain that selecting 3;000 ft. and continuing the descent once cleared for the visual would had put us close to the highest obstacle stated in the approach plate. I will keep this in consideration for future flights to come ensuring we are not at a lower altitude than the MSA not established on a final approach course as well as keeping in mind obstacles around us at all times.


Synopsis: Flight crew reported receiving an obstacle alert on a night visual approach to OKC.