Narrative:

A couple weird things happened during our arrival to ord today. Descending on the veeck 1 near hanni; ord TRACON told us to maintain 280 KTS. We were descending at 280 at the time; around 11;000 ft; in LNAV/VNAV. About a minute after our level off at 11;000 ft; the controller told us again; he needed us to maintain the 280 KTS. We looked down and we were at 250 KTS. The airplane had slowed itself; and we really have no idea why. To our knowledge; the automation was set up correctly; and we verified the correct settings were still in place after the controller noticed the slowdown. We sped back up.a few minutes later the controller told us to maintain 180 KTS. We thought this was odd; since it was a 100 KTS slowdown right after he told us to maintain 280. After we slowed down; somewhat ironically the controller came on and said he needed us to speed back up to 250 (now below 10;000); and that he had given the slowdown to the wrong airplane. We sped back up again.finally; we were vectored to an intercept for the ILS 10R; autopilot and automation on; approach mode armed for the capture. The airplane flew right through the localizer without as much as a wing rock. We caught it immediately as it was happening and started a manual turn back. However; the controller noticed too; told us we had passed through the localizer and gave us a new vector back on from the other side. He then re-cleared us to the approach. The concern here is traffic separation on the parallel runways. Again; we have no idea why the airplane did this. All correct modes were verified before and after the event.

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Original NASA ASRS Text

Title: An air carrier automation fully active on an ORD VEECK 1 did not appear to honor the selected modes when it failed to maintain a SPD Select during level off and then failed to capture an armed APP LOC.

Narrative: A couple weird things happened during our arrival to ORD today. Descending on the VEECK 1 near HANNI; ORD TRACON told us to maintain 280 KTS. We were descending at 280 at the time; around 11;000 FT; in LNAV/VNAV. About a minute after our level off at 11;000 FT; the controller told us again; he needed us to maintain the 280 KTS. We looked down and we were at 250 KTS. The airplane had slowed itself; and we really have no idea why. To our knowledge; the automation was set up correctly; and we verified the correct settings were still in place after the Controller noticed the slowdown. We sped back up.A few minutes later the Controller told us to maintain 180 KTS. We thought this was odd; since it was a 100 KTS slowdown right after he told us to maintain 280. After we slowed down; somewhat ironically the controller came on and said he needed us to speed back up to 250 (now below 10;000); and that he had given the slowdown to the wrong airplane. We sped back up again.Finally; we were vectored to an intercept for the ILS 10R; autopilot and automation ON; Approach mode armed for the capture. The airplane flew right through the LOC without as much as a wing rock. We caught it immediately as it was happening and started a manual turn back. However; the Controller noticed too; told us we had passed through the LOC and gave us a new vector back on from the other side. He then re-cleared us to the approach. The concern here is traffic separation on the parallel runways. Again; we have no idea why the airplane did this. All correct modes were verified before and after the event.

Data retrieved from NASA's ASRS site and automatically converted to unabbreviated mixed upper/lowercase text. This report is for informational purposes with no guarantee of accuracy. See NASA's ASRS site for official report.