Flight crew reports misunderstanding controller issuing new runway assignment and new altitude. Flig...

Attributes
ACN	772021
Time
Date	200801
Local Time Of Day	1201 To 1800
Place
Locale Reference	airport : zggg.airport
State Reference	FO
Altitude	msl single value : 11800
Environment
Flight Conditions	VMC
Light	Daylight
Aircraft 1
Operator	common carrier : air carrier
Make Model Name	MD-11
Operating Under FAR Part	Part 121
Navigation In Use	other
Flight Phase	descent : intermediate altitude
Route In Use	arrival star : n/a
Flight Plan	IFR
Person 1
Affiliation	company : air carrier
Function	flight crew : first officer
Experience	flight time last 90 days : 120 flight time total : 4200 flight time type : 220
ASRS Report	772021
Person 2
Affiliation	government : foreign
Function	controller : radar
Events
Anomaly	altitude deviation : overshoot non adherence : clearance
Independent Detector	other controllera
Resolutory Action	controller : issued advisory flight crew : returned to assigned altitude
Supplementary
Problem Areas	Flight Crew Human Performance ATC Human Performance
Primary Problem	Flight Crew Human Performance

Narrative:

On descent into zggg; we leveled off at the assigned altitude (in meters) and had reset our altimeters to the local altimeter setting because we thought we heard the controller use the phrase 'nonstandard' with the altitude assigned. A few minutes later; the controller told us that he showed us 100 meters low and we confirmed that we were at the assigned altitude. We confirmed that all of altimeters were at the local altimeter setting and asked the controller again for his reading of our altitude. We didn't receive a response and discussed the possibility that he had said 'standard' with the assigned altitude. We reset our altimeters to standard and continued on the approach with no further discussion with the controller about our altitude. I believe that we may have been 100 meters low for about 5 NM due to the confusion about the controller's usage of the word standard. I also believe that we were all a little fatigued due to the previous day's flight and were also given a different approach and runway at the airfield close to the descent point; along with the altitude assignment. This caused the crew to focus on the FMS changes and pulling out different approach plates within a short distance form the descent point. This may have distracted us enough to misunderstand the controller's instructions on standard/nonstandard altimeter setting for the assigned altitude.

Original NASA ASRS Text

Title: FLT CREW REPORTS MISUNDERSTANDING CONTROLLER ISSUING NEW RWY ASSIGNMENT AND NEW ALTITUDE. FLT CREW SETS QNH PRIOR TO DESCENDING BELOW TRANSITION LEVEL.

Narrative: ON DESCENT INTO ZGGG; WE LEVELED OFF AT THE ASSIGNED ALTITUDE (IN METERS) AND HAD RESET OUR ALTIMETERS TO THE LOCAL ALTIMETER SETTING BECAUSE WE THOUGHT WE HEARD THE CONTROLLER USE THE PHRASE 'NONSTANDARD' WITH THE ALTITUDE ASSIGNED. A FEW MINUTES LATER; THE CONTROLLER TOLD US THAT HE SHOWED US 100 METERS LOW AND WE CONFIRMED THAT WE WERE AT THE ASSIGNED ALTITUDE. WE CONFIRMED THAT ALL OF ALTIMETERS WERE AT THE LOCAL ALTIMETER SETTING AND ASKED THE CONTROLLER AGAIN FOR HIS READING OF OUR ALTITUDE. WE DIDN'T RECEIVE A RESPONSE AND DISCUSSED THE POSSIBILITY THAT HE HAD SAID 'STANDARD' WITH THE ASSIGNED ALTITUDE. WE RESET OUR ALTIMETERS TO STANDARD AND CONTINUED ON THE APPROACH WITH NO FURTHER DISCUSSION WITH THE CONTROLLER ABOUT OUR ALTITUDE. I BELIEVE THAT WE MAY HAVE BEEN 100 METERS LOW FOR ABOUT 5 NM DUE TO THE CONFUSION ABOUT THE CONTROLLER'S USAGE OF THE WORD STANDARD. I ALSO BELIEVE THAT WE WERE ALL A LITTLE FATIGUED DUE TO THE PREVIOUS DAY'S FLIGHT AND WERE ALSO GIVEN A DIFFERENT APPROACH AND RUNWAY AT THE AIRFIELD CLOSE TO THE DESCENT POINT; ALONG WITH THE ALTITUDE ASSIGNMENT. THIS CAUSED THE CREW TO FOCUS ON THE FMS CHANGES AND PULLING OUT DIFFERENT APPROACH PLATES WITHIN A SHORT DISTANCE FORM THE DESCENT POINT. THIS MAY HAVE DISTRACTED US ENOUGH TO MISUNDERSTAND THE CONTROLLER'S INSTRUCTIONS ON STANDARD/NONSTANDARD ALTIMETER SETTING FOR THE ASSIGNED ALTITUDE.

Data retrieved from NASA's ASRS site as of May 2009 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.

Flight crew reports misunderstanding controller issuing new runway assignment and new altitude. Flight crew sets qnh prior to descending below transition level.