Flight Crew Air Transport Pilot (ATP)
ATC Issue All Types; Conflict Airborne Conflict; Deviation - Altitude Excursion From Assigned Altitude; Deviation / Discrepancy - Procedural Published Material / Policy
Air Traffic Control Issued Advisory / Alert; Flight Crew Took Evasive Action
Human Factors; Airspace Structure
Inbound from waypoint STERE on the RNP Y 22L at 3000'; we heard ATC communicating with an aircraft northwest of our position about the several [other aircraft] lined up flying the approach into MDW. As we approached that aircraft our TCAS display indicated that the target aircraft was 100' below us and level; heading south towards our lateral course. The Pilot Monitoring communicated this to ATC. ATC cleared us to deviate north (right) of course to avoid the aircraft. I Pilot Flying (PF) immediately engaged CWS and began a right turn; level at 3000'. While in the turn we received a TA alert. The Pilot Monitoring called out we were clear of the aircraft so I turned left and intercepted the approach course and engaged LNAV/VNAV and setting the altitude window to 1500'. Approaching waypoint SAILZ; ATC alerted us to another aircraft approaching our path ahead. At SAILZ this aircraft triggered a Resolution Advisory (RA). The RA red command box indicated I could not descend. So I disconnected the autopilot and maintained 3000'-3100'. After we were 'Clear of Conflict' I accessed and communicated that we were high on the approach path. Still hand flying I began to descend to intercept the descent path.Approaching the lake shore; we encountered another Traffic Alert (TA) alert. Both Pilot Monitoring and I looked but could not see either an aircraft outside or on our displays. This third traffic alert distracted us just as we approached the FMS descent path. I then realized we were approaching 2100' MSL just outside KEEEL. I corrected our flight path and rejoined our descent path at KEEEL. I then continued to hand fly the approach to a landing.Trying to fly an instrument approach procedure in VFR weather with several VFR aircraft flying in the vicinity of the approach creates challenges not encountered when in IMC. Abandoning the RNAV Y Approach and requesting vectors to a visual approach would have decreased our workload on the approach. When I began my descent to recapture the glidepath after the RA; I should have called for the Pilot Monitoring to reset the altitude window to 2400.
While cleared direct to SAILZ at 3000'; we heard Approach talking to VFR general aviation traffic at 2900'. They pointed out three aircraft; including us; to him as potential conflicts as he was crossing our approach path. The 2900' traffic was pointed out to us at two miles just as it showed as a Traffic Alert (TA). We called visual and were given permission to turn as required to avoid the traffic. The First Officer (FO) did a great job of turning right towards his tail avoiding a certain RA. We then re-engaged automation direct SAILZ to finish the approach. Over SAILZ we got another TA which quickly changed to an RA to 'Monitor Vertical Speed' preventing the necessary descent on the approach out of SAILZ.Once again; the (FO) did a great job of complying with the RA but found himself high on profile inside SAILZ when we were 'Clear of Conflict'. He announced his selection of vertical speed to try to get back on profile. I informed ATC that we were off profile on the approach due to an RA. While correcting; we got another TA with no target shown. There was a moment of confusion as the traffic info was shown in text on the right side of the PFD but not displayed as a target (behind us). These few seconds of uncertainty distracted us long enough to descend below profile; which I announced. The FO corrected and crossed KEEEL at 2100'; 300 below the 2400' crossing. The FO hand-flew the remainder of the approach to an uneventful landing. There was no comment from ATC on the altitude deviation for the third TCAS event on final as we were still maneuvering for the second event. This also occurred right with the switch to Tower over KEEEL. I heard no comments from any Passengers about the event. When on the ground we debriefed the event. I was then distracted by operational events during the turn and neglected to inform Dispatch of the RA.Establish a VFR corridor to de-conflict general aviation traffic from this often-used approach procedure. At a minimum ATC should direct altitude de-confliction to general aviation traffic under flight following over the lake front.
B737 flight crew experienced three separate TCAS events during a visual approach into MDW.