Air carrier flight crew reported bank angle and sink rate aural warnings during approach. Crew corrected and continued for an uneventful landing.
Synopsis
Air carrier flight crew reported bank angle and sink rate aural warnings during approach. Crew corrected and continued for an uneventful landing.
Narrative
On our final leg into DCA; we conducted the RNAV approach to Runway 19. The Captain was the Pilot Flying (PF); and I was the Pilot Monitoring (PM). After passing the WIRSO waypoint; a quartering crosswind contributed to a lateral overshoot of the runway centerline. Corrective control inputs resulted in a brief over-bank condition; at which time I made a 'Bank Angle' callout; and the condition was promptly corrected by the PF.Subsequent corrections led to a deviation above the glide path; prompting me to make a 'Path' callout. In an effort to regain the vertical profile; the descent rate increased to greater than 1;000 feet per minute; which generated a GPWS 'Sink Rate' alert. In response; I verbally called for a go-around. At approximately 100 feet AGL; multiple GPWS alerts were occurring simultaneously; and I believe my go-around call was masked by the concurrent aural warnings.The aircraft continued to touchdown; with the landing occurring approximately 2;000 feet beyond the runway threshold. After touchdown; the remainder of the rollout and subsequent operations were uneventful.Following the flight; the Captain and I discussed the approach and agreed that the approach no longer met stabilized approach criteria and that an earlier; more assertive go-around decision would have been the appropriate course of action. This event reinforced the importance of early recognition of destabilizing factors; clear and timely go-around communication; and a shared commitment to discontinuing an approach when stabilized approach parameters are not met; regardless of altitude.Cause: Challenging crosswind conditions and increased workload during the final segment of the RNAV approach placed additional demands on lateral and vertical path management. Efforts to correct these deviations resulted in the approach no longer meeting stabilized approach criteria and reduced touchdown margin. This event highlights the value of early stabilization; proactive energy management; and timely go-around decisions when conditions or workload begin to erode approach stability.
Second reporter narrative
Winds at DCA were very strong and gusty (250@18G35); with RNAV RWY 19 approaches in use. These conditions created a 31 knot cross wind component; close to our limit of 33 knots. The F/O and I briefed the approach with winds and potential for airspeed/altitude fluctuations being a threat. During the final turn to the runway the winds were pushing us to the east; forcing a steeper bank turn to the right which triggered a 'Bank Angle' message. The message was broadcast as I was already rolling out of the turn and when I looked at the attitude indicator in the Head-up Display (HUD) it was already showing less than 30 degrees of bank. I stated 'transient' and continued the approach. As we continued the approach the wind gusts were evident with the airspeed and vertical speed fluctuating; and I was steadily using my hand to dampen out the abrupt movement of the autothrottles. At about 100 feet AGL the GPWS triggered a 'Sink Rate' message twice in rapid succession. After the first message and while the second message was being broadcast I observed the vertical speed change from 1100 fpm to 900 fpm. Shortly after I heard the F/O say; 'we have a Sink Rate' to which I responded 'transient'. I elected to continue the approach to landing based on our earlier briefing of expected airspeed/altitude fluctuations and the fact we were in position to make a landing in the first 1/3 of the runway. We touched down at the intersection of runways 19/15 and the rest of the landing/taxi in was uneventful. Later when discussing the approach; the F/O stated he called 'Go Around' during the Sink Rate broadcasts. I apologized and explained to him I did not hear the call; otherwise I would have initiated an immediate go around. After further discussion we concluded he probably made the call while the second 'Sink Rate' broadcast was being made; and the louder volume of the broadcast prevented me from hearing his 'Go Around' call. Cause: The strong and gusty winds close to the aircraft's crosswind limit. The wind direction pushing the aircraft to the east requiring an earlier turn/steeper angle of bank to remain in position for landing on RWY 19. The wind direction and speed causing a higher degree of mechanical turbulence close to the surface immediately downstream of the airport terminal. The volume of the 'Sink Rate' broadcast overriding the volume of the F/O voice.
Source: NASA Aviation Safety Reporting System (public domain). Reports are voluntary submissions and are not verified by NASA.