Date: 201504
Local time of day: 1201-1800
Location: MKE.Airport, WI
Flight conditions: VMC
Light: Daylight
Aircraft: Commercial Fixed Wing
Operator: Air Carrier
Operating under: Part 121
Mission: Passenger
Flight phase: Initial Approach
Airspace: Class C MKE
ATC / advisory: TRACON MKE
Aircraft component: Altimeter
Component problem: Improperly Operated
Reporter organization: Air Carrier
Reporter function: Captain; Pilot Flying
Reporter qualification: Flight Crew Air Transport Pilot (ATP)
Human factors: Confusion; Other / Unknown; Situational Awareness; Workload
Anomaly: Deviation - Altitude Overshoot; Deviation / Discrepancy - Procedural Clearance; Deviation / Discrepancy - Procedural Published Material / Policy; Inflight Event / Encounter CFTT / CFIT
Detector: Person Air Traffic Control
When detected: In-flight
Result: Air Traffic Control Issued Advisory / Alert; Flight Crew Became Reoriented; Flight Crew Returned To Clearance
Contributing factors: ATC Equipment / Nav Facility / Buildings; Human Factors
Primary problem: Human Factors

Narrative: During climb out; I put the ACARS digital ATIS function on auto-updates as soon as we climbed above 10;000 feet. I knew the weather situation was going to be changing rapidly in MKE; because a frontal system was moving through the upper Midwest. The Terminal Area Forecast (TAF) was calling for rain to give way to an improving trend throughout the forecast period. It was also forecasting gusty winds from the west.The initial digital ATIS we received from MKE indicated that they were using the Localizer approach to Runway 25L; and that the winds were gusty; but the visibility was good under a medium-to-low overcast. About an hour later; we received a new digital ATIS that indicated the winds had died down considerably and that MKE was now landing on Runway 1L. We loaded and briefed the ILS to 1L. During descent; we ran the descent checklist (including checking the altimeter setting) during the descent. The altimeter setting that we had written down on the TOLD card for MKE was 29.44 inches. That seemed unusually low to me; so I asked my first officer to double-check it. He pulled up the newest digital ATIS report from MKE; which we had just received; and this report said the altimeter was approximately 30.26 inches (I don't recall exactly; but I believe it was 30.26 inches....whatever it was; it was significantly higher than 29.44 inches). It's important to note that I don't recall checking the time stamp on this newest ATIS report. It had arrived automatically; so I believed it was the most up to date ATIS report available.Chicago Center had us on pretty much a continuous; flight idle descent toward MKE; as we had been kept somewhat high during our arrival (I'm presuming this is because ORD arrivals under us prevented lower altitudes sooner. From the time we left FL180 until we were cleared for the approach; we never leveled off a single time.We were cleared to cross LYSTR at 11;000 feet and to intercept the Localizer for 25L at LYSTR. The first officer queried the Chicago Center controller about this; because our digital ATIS was reporting that MKE was landing on 1L. The controller called MKE on the landline; and came back and reported to us that they were still landing on Runway 25L; that our previous clearance was in effect; and to contact MKE Approach. I also don't recall whether we checked in with the ATIS code; or whether the controller acknowledged it. I was caught off-guard by the runway switch and was pulling out my chart for the new approach; so I wasn't closely monitoring the radio at that exact moment.We were now somewhat behind the power curve; mentally speaking. We had briefed for a precision approach to one runway; and were now being told to plan for a straight-in nonprecision approach at the last minute. We were now about 30 miles from the airport; continuing our descent; and we had to now plan for a completely different approach (including a switch to a non-precision approach); and a different taxi route. We got the briefing completed; but I was feeling a little bit rushed.We were eventually cleared for the Localizer Approach and we began descending on profile at the stepdown fixes. Upon reaching 2500 feet MSL prior to the FAF; we broke out of the clouds and we could see we were over Lake Michigan. It looked like we were lower than normal for being so far away from the airport; but nonprecision approaches can be deceptive; so I didn't think much else about it. My first officer mentioned something about the radar altimeter indicating that we were only 1300 feet above the surface; but his comment didn't completely register with me at the time. I don't recall him expressing any serious concern over this fact; and I took it to mean he was just giving it to me as a means of situational awareness. We crossed the FAF and began descending toward 1200 feet MSL; which was the MDA. At about this time; the controller asked us to verify our altimeter setting was 29.44 inches. We replied we had 30.26. He told us he thought we were a little low; and that the altimeter at the field was showing 29.44. When I dialed in the new altimeter setting; our altimeter readout jumped from approximately 2;000 feet MSL to about 1300 feet MSL. The autopilot immediately captured the preset altitude of 1200 feet. We did not descend out of MDA until the runway and Precision Approach Path Indicator (PAPI) was in sight; and when we were about two miles from the runway; in a position to land.On the way back; I discovered that the digital ATIS reports I was receiving were erroneous. I received multiple ATIS reports within minutes of each other; with each one time stamped from a different part of the day. Some of the reports looked like reports I had seen the day prior when a storm front passed through. When comparing the time stamps with the actual current time; some of the reports appeared to be at least 12 hours old (if not older).As crazy as this sounds; I think something went wrong with either [airborne data communications]; the FAA computers; or with our company computer network; and the digital ATIS reports that were being sent to air crews for a while were archived ATIS reports from a day or more prior. I confirmed this by talking with a couple of other crews who had experienced weird ATIS problems. My dispatcher said he had received at least one other report indicating there was a problem there as well.Having a current altimeter setting is absolutely crucial; especially on a nonprecision approach. There are so many red flags that could have caught this issue before the controller queried us:(1) The fact that the ATIS was reporting Runway 1L was in use when the controllers told us to expect 25L(2) The fact that we just looked low when I leveled out over Lake Michigan prior to the FAF.(3) The radar altimeter could have alerted us to the fact that as we crossed the FAF; we were about 500 - 700 feet lower than expected.  However; I've seen the radar altimeter on this airplane act a little weird over water-based surfaces; so it would have been easy to discount the radar altimeter readout since our approach was over Lake Michigan.(4) That feeling of being rushed should have alerted me to the fact that I was going to be too preoccupied to monitor the radio when the pilot monitoring checked in with the controller. Any time I'm feeling rushed in an airplane; that should be a signal to me that something's going to get missed.(5) Perhaps it's wise to ask for the RNAV/GPS approach in nonprecision approach situations; if one is available. The virtual 'snowflake' glidepath guidance would have provided better situational awareness about where we were in relationship to the vertical profile.(6) ALWAYS; ALWAYS; ALWAYS check the time stamp on the digital ATIS!




Synopsis: A Regional Jet Captain reports being advised by ATC during a non-precision approach to MKE that he is low. The altimeter setting was actually 29.44 instead of the 30.26 setting obtained from the digital ATIS received over ACARS.