Date: 201906
Local time of day: 1801-2400
Location: BOI.Airport, ID
Aircraft: Commercial Fixed Wing
Operator: Air Carrier
Operating under: Part 121
Flight plan: IFR
Mission: Passenger
Flight phase: Final Approach
Reporter organization: Air Carrier
Reporter function: Captain; Pilot Flying
Reporter qualification: Flight Crew Multiengine; Flight Crew Air Transport Pilot (ATP); Flight Crew Instrument
Human factors: Situational Awareness
Second reporter function: First Officer; Pilot Not Flying
Anomaly: Deviation / Discrepancy - Procedural Published Material / Policy; Inflight Event / Encounter Weather / Turbulence; Inflight Event / Encounter CFTT / CFIT
Detector: Automation Aircraft Terrain Warning
When detected: In-flight
Result: Flight Crew Became Reoriented; Flight Crew Took Evasive Action
Contributing factors: Human Factors
Primary problem: Human Factors

Narrative: On visual approach to 28L in BOI. Aircraft was slightly overweight for landing. I requested a 10 mile final to burn additional fuel to ensure under max landing weight. We were told speed was at our discretion; so I configured the aircraft at flaps 35 to facilitate burning off fuel quicker. ATC turned us to base. As I verified we would be under 62;000 LBS upon landing; my airspeed was fluctuating due some turbulence. I was concerned with not over speeding the flaps. The FO (First Officer) had to call 'airspeed' twice to warn me speed was rising. We did not over speed the flaps. At this time; I called the field in sight. ATC cleared us for the visual to 29L. Still struggling to control my airspeed; I called for the FO to set '4;000' in the altitude alerted for pattern altitude; which he did. Pattern altitude is 4;500 feet in BOI. I called for the wrong altitude be set. I'm not certain I briefed the pattern altitude along with the approach brief. As I rolled final and was descending toward pattern altitude I got a ground proximity alert due to rising terrain in the area. I added power and increased pitch to begin a potential MAP. Just then the warning ceased. The terrain was in sight. The field was in sight. The aircraft was on the glide path and airspeed was stable; so I opted to continue the approach to landing. Be certain to brief visual pattern altitude and stick to it so that both pilots are on the same page when it comes to actually flying the pattern.


Second narrative: Today on a visual approach to Runway 28L we experienced a GPWS alert while turning final. Approach Control was vectoring us out for a long final because we needed to burn fuel in order to be under landing weight. The Captain decided to configure early for landing to increase drag and to not fly too far away from the airport. Approach had us at 5;000 feet MSL and gave us the final vector to intercept final and cleared us for the visual approach for 28L. At this point the Captain asked for pattern altitude and started descending. We received a message in the FMS for a low altitude alert during our turn to final; and I announced this to the Captain. At this point we were over terrain that was descending and everything looked normal as we were pointed to the runway with no terrain/ obstacle/ or threat in the path of the aircraft. On final all of a sudden we received the GPWS alert; right away the Captain kicked off the auto pilot and leveled off and even climbed to gain altitude to stop the alert. We were 100% VMC and the airplane never entered an unstable or undesired aircraft state. Since we were on final and stable while configured we continued the approach and landed safely in BOI. Terrain was never a threat; and the alert was a surprise since we were already on final with no obstacles in front of us. No deviations from ATC; no aircraft limitations were exceeded; and no safety hazards were experienced. A lesson learned would be to watch your rate of descent when you are near terrain; as if it is too high momentarily you may set of the GPWS.


Synopsis: Commercial Fixed Wing flight crew reported receiving a GPWS terrain warning on a visual approach to BOI.