Cleared traffic through altitude of descending aircraft. Changed clearance.

Attributes
ACN	106471
Time
Date	198903
Day	Sun
Local Time Of Day	1801 To 2400
Place
Locale Reference	atc facility : svm
State Reference	MI
Altitude	msl bound lower : 28000 msl bound upper : 28500
Environment
Flight Conditions	VMC
Light	Daylight
Aircraft 1
Controlling Facilities	artcc : zob artcc : zau
Operator	common carrier : air carrier
Make Model Name	Large Transport, Low Wing, 2 Turbojet Eng
Navigation In Use	Other
Flight Phase	climbout : intermediate altitude
Route In Use	enroute : direct enroute airway : zau enroute airway : zob
Flight Plan	IFR
Person 1
Affiliation	company : air carrier
Function	flight crew : first officer
Qualification	pilot : flight engineer pilot : cfi pilot : atp
Experience	flight time last 90 days : 100 flight time total : 7400 flight time type : 100
ASRS Report	106471
Person 2
Affiliation	company : air carrier
Function	flight crew : captain oversight : pic
Qualification	pilot : atp
Events
Anomaly	other anomaly other
Independent Detector	other controllera
Resolutory Action	controller : issued new clearance
Consequence	Other
Supplementary
Primary Problem	ATC Human Performance
Air Traffic Incident	Inter Facility Coordination Failure other

Narrative:

On J70 wbound between svm and pmm at approximately alphe intersection. Climb out out of dtw ZOB cleared to maintain FL230 280 KTS, maximum speed, then reclred to climb to FL290 and 290 KTS maximum speed. Captain flying aircraft on autoplt, first officer handling communications. First officer read back FL290 and 290 KTS. First officer entered FL290 in altitude window. Captain acknowledged FL290 and 290 KTS. Received frequency change to ord center. First officer checked on with call sign and gave 'FL280 for FL290,' ord controller immediately responded to maintain FL280. Altitude hold was immediately engaged at FL280 but aircraft drifted to approximately FL280.5 before descent back to FL280. Center had right to left overtaking crossing traffic at FL290 same direction. When asked about problem controller said there was a conflict, but saw no need to involve pilots.

Original NASA ASRS Text

Title: CLRED TFC THROUGH ALT OF DESCENDING ACFT. CHANGED CLRNC.

Narrative: ON J70 WBOUND BTWN SVM AND PMM AT APPROX ALPHE INTXN. CLBOUT OUT OF DTW ZOB CLRED TO MAINTAIN FL230 280 KTS, MAX SPD, THEN RECLRED TO CLB TO FL290 AND 290 KTS MAX SPD. CAPT FLYING ACFT ON AUTOPLT, F/O HANDLING COMS. F/O READ BACK FL290 AND 290 KTS. F/O ENTERED FL290 IN ALT WINDOW. CAPT ACKNOWLEDGED FL290 AND 290 KTS. RECEIVED FREQ CHANGE TO ORD CENTER. F/O CHKED ON WITH CALL SIGN AND GAVE 'FL280 FOR FL290,' ORD CTLR IMMEDIATELY RESPONDED TO MAINTAIN FL280. ALT HOLD WAS IMMEDIATELY ENGAGED AT FL280 BUT ACFT DRIFTED TO APPROX FL280.5 BEFORE DSCNT BACK TO FL280. CENTER HAD RIGHT TO LEFT OVERTAKING XING TFC AT FL290 SAME DIRECTION. WHEN ASKED ABOUT PROB CTLR SAID THERE WAS A CONFLICT, BUT SAW NO NEED TO INVOLVE PLTS.

Data retrieved from NASA's ASRS site as of August 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.