Altitude deviation. Miscom on assigned altitude.

Attributes
ACN	317330
Time
Date	199510
Day	Wed
Local Time Of Day	0601 To 1200
Place
Locale Reference	airport : clt
State Reference	NC
Altitude	msl bound lower : 4250 msl bound upper : 4600
Environment
Flight Conditions	IMC
Light	Daylight
Aircraft 1
Controlling Facilities	tracon : clt
Operator	common carrier : air carrier
Make Model Name	MD-80 Super 80
Operating Under FAR Part	Part 121
Flight Phase	descent : approach descent other
Flight Plan	IFR
Person 1
Affiliation	company : air carrier
Function	flight crew : captain oversight : pic
Qualification	pilot : flight engineer pilot : atp pilot : commercial pilot : instrument
Experience	flight time last 90 days : 150 flight time total : 12000 flight time type : 2100
ASRS Report	317330
Person 2
Affiliation	company : air carrier
Function	flight crew : first officer
Qualification	pilot : atp
Events
Anomaly	altitude deviation : overshoot non adherence : clearance
Independent Detector	other flight crewa
Resolutory Action	flight crew : returned to intended course or assigned course other
Consequence	Other
Supplementary
Primary Problem	Flight Crew Human Performance
Air Traffic Incident	Pilot Deviation

Narrative:

Turned downwind at 6000 ft heading 180 degrees 170 KTS for vectors to ILS runway 36R. Heavy traffic arriving and departing. IMC with moderate to occasional heavy rain through area. Clearance received and acknowledged by captain to descend to 4000 ft. First officer flying aircraft on autoplt. First officer set altitude alerter to 4000 ft and confirmed. Passing 4300 ft controller radioed and said altitude was 4600 ft. Immediate reversal made back to 4600 ft as captain replied that flight was cleared to 4000 ft. TCASII issued 'monitor descent' as the reversal was made. First officer then said I thought I heard 4600 ft for the clearance but when captain acknowledged 4000 ft and controller didn't correct, he assumed he misheard and set 4000 ft in alerter. During earlier portion of flight first officer misheard a clearance so captain re- confirmed clearance with ATC. This occasion being reported, first officer did not ask to clarify the clearance, perhaps because he misheard earlier clearance. As always, if in doubt, ask. Communications and cockpit atmosphere was friendly and supportive throughout flight. I cannot explain the communications failure in this case except possible hesitation due to earlier mishear by first officer and not wanting to repeat same type of error.

Original NASA ASRS Text

Title: ALTDEV. MISCOM ON ASSIGNED ALT.

Narrative: TURNED DOWNWIND AT 6000 FT HDG 180 DEGS 170 KTS FOR VECTORS TO ILS RWY 36R. HVY TFC ARRIVING AND DEPARTING. IMC WITH MODERATE TO OCCASIONAL HVY RAIN THROUGH AREA. CLRNC RECEIVED AND ACKNOWLEDGED BY CAPT TO DSND TO 4000 FT. FO FLYING ACFT ON AUTOPLT. FO SET ALT ALERTER TO 4000 FT AND CONFIRMED. PASSING 4300 FT CTLR RADIOED AND SAID ALT WAS 4600 FT. IMMEDIATE REVERSAL MADE BACK TO 4600 FT AS CAPT REPLIED THAT FLT WAS CLRED TO 4000 FT. TCASII ISSUED 'MONITOR DSCNT' AS THE REVERSAL WAS MADE. FO THEN SAID I THOUGHT I HEARD 4600 FT FOR THE CLRNC BUT WHEN CAPT ACKNOWLEDGED 4000 FT AND CTLR DIDN'T CORRECT, HE ASSUMED HE MISHEARD AND SET 4000 FT IN ALERTER. DURING EARLIER PORTION OF FLT FO MISHEARD A CLRNC SO CAPT RE- CONFIRMED CLRNC WITH ATC. THIS OCCASION BEING RPTED, FO DID NOT ASK TO CLARIFY THE CLRNC, PERHAPS BECAUSE HE MISHEARD EARLIER CLRNC. AS ALWAYS, IF IN DOUBT, ASK. COMS AND COCKPIT ATMOSPHERE WAS FRIENDLY AND SUPPORTIVE THROUGHOUT FLT. I CANNOT EXPLAIN THE COMS FAILURE IN THIS CASE EXCEPT POSSIBLE HESITATION DUE TO EARLIER MISHEAR BY FO AND NOT WANTING TO REPEAT SAME TYPE OF ERROR.

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.