A321
Flight Crew Air Transport Pilot (ATP)
Communication Breakdown; Time Pressure
Deviation - Speed All Types; Deviation / Discrepancy - Procedural Clearance; Deviation / Discrepancy - Procedural Published Material / Policy
Flight Crew FLC Overrode Automation; General Maintenance Action
Human Factors; Weather
We were conducting the RNAV 27 approach in Day VMC conditions to SAN with a Tailwind during most of the Arrival and initial Approach phase. The Captain was the Pilot Flying. When Cleared for the approach he followed the typical routine of arming Approach Mode which quickly captured lateral and vertical guidance and began descending on the glideslope. At the time we were at flaps one with about 10-15 kts buffer under the Flaps 1 redline of 235. Because of the tailwind and the somewhat steeper than normal approach angle; the aircraft started to accelerate after capturing the glideslope and quickly oversped the flaps by approximately 5-10 kts. The Captain began to intervene immediately with use of the speedbrakes but the acceleration trend carried us into the red line. After removing the aircraft from approach mode and taking us off the glideslope; the aircraft slowed below the red line and we continued configuring and landed normally. We wrote up the overspeed at the Gate in SAN.I believe that the core reason for this was a misunderstanding on the part of the PF (Pilot Flying) about what the aircraft would do once approach was armed. The PF said repeatedly that he thought the aircraft wouldn't overspeed with the automation set up with a selected speed and Approach Captured. Because of the tailwind and the aircraft's priority to follow the glideslope without regard to selected speed; an overspeed was possible. He may have been thinking of flight envelope protections in normal mode which would have protected an extreme overspeed but will allow the aircraft into the redline before they intervene.As the PM (Pilot Monitoring); I should have spoken up when approach mode was about to capture the glideslope to caution that an overspeed was possible. We had briefed during the approach briefing that a threat in SAN was the likelihood of being fast and high but I will add in the future that flap overspeeds; especially on the initial stage of the approach are possible. Additional emphasis in training about automation priorities where the aircraft will follow vertical guidance without regard to airspeeds may also be beneficial.
A321 First Officer reported flap overspeed during a coupled approach with a tailwind.