Ord local controller issues confusing taxi instructions to an MD80 crew during landing.

Attributes
ACN	519084
Time
Date	200107
Day	Thu
Local Time Of Day	1201 To 1800
Place
Locale Reference	airport : ord.airport
State Reference	IL
Altitude	agl single value : 0
Aircraft 1
Controlling Facilities	tower : dfw.tower
Operator	common carrier : air carrier
Make Model Name	MD-80 Super 80
Operating Under FAR Part	Part 121
Flight Phase	landing : roll
Flight Plan	IFR
Aircraft 2
Controlling Facilities	tower : ord.tower
Operator	common carrier : air carrier
Make Model Name	Commercial Fixed Wing
Operating Under FAR Part	Part 121
Flight Phase	ground : taxi
Flight Plan	IFR
Person 1
Affiliation	company : air carrier
Function	flight crew : captain oversight : pic
Qualification	pilot : atp
ASRS Report	519084
Person 2
Affiliation	company : air carrier
Function	flight crew : first officer
Events
Anomaly	non adherence : published procedure
Independent Detector	other flight crewa other flight crewb
Resolutory Action	none taken : anomaly accepted
Supplementary
Problem Areas	ATC Human Performance Flight Crew Human Performance
Primary Problem	ATC Human Performance

Narrative:

We were cleared to land on runway 4R close behind another aircraft. On touchdown, we were planning to turn off runway 4R at the end of the runway. ATIS instructed us not to turn off taxiway Q unless instructed to do so. Approximately 1/2 way down runway 4R we were instructed to turn off as the aircraft in front of us did. This caused some confusion and was a late change of plan. The potential for an accident increases when major ATC instructions occur on landing rollout. I believe all ATC runway instruction changes should be kept to a minimum for cockpit crews while they are on landing rollout. Supplemental information from can 519085: this caused some confusion as we were not sure what the previous aircraft had done. Rollout instructions should be clear, ie, expedite turn off at taxiway Q, and should not depend on the air crew to remember directions for previous aircraft.

Original NASA ASRS Text

Title: ORD LCL CTLR ISSUES CONFUSING TAXI INSTRUCTIONS TO AN MD80 CREW DURING LNDG.

Narrative: WE WERE CLRED TO LAND ON RWY 4R CLOSE BEHIND ANOTHER ACFT. ON TOUCHDOWN, WE WERE PLANNING TO TURN OFF RWY 4R AT THE END OF THE RWY. ATIS INSTRUCTED US NOT TO TURN OFF TXWY Q UNLESS INSTRUCTED TO DO SO. APPROX 1/2 WAY DOWN RWY 4R WE WERE INSTRUCTED TO TURN OFF AS THE ACFT IN FRONT OF US DID. THIS CAUSED SOME CONFUSION AND WAS A LATE CHANGE OF PLAN. THE POTENTIAL FOR AN ACCIDENT INCREASES WHEN MAJOR ATC INSTRUCTIONS OCCUR ON LNDG ROLLOUT. I BELIEVE ALL ATC RWY INSTRUCTION CHANGES SHOULD BE KEPT TO A MINIMUM FOR COCKPIT CREWS WHILE THEY ARE ON LNDG ROLLOUT. SUPPLEMENTAL INFO FROM CAN 519085: THIS CAUSED SOME CONFUSION AS WE WERE NOT SURE WHAT THE PREVIOUS ACFT HAD DONE. ROLLOUT INSTRUCTIONS SHOULD BE CLR, IE, EXPEDITE TURN OFF AT TXWY Q, AND SHOULD NOT DEPEND ON THE AIR CREW TO REMEMBER DIRECTIONS FOR PREVIOUS ACFT.

Data retrieved from NASA's ASRS site as of July 2007 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.