Possible altitude overshoot in climb for air carrier medium large transport in mexico.

Attributes
ACN	164295
Time
Date	199011
Day	Tue
Local Time Of Day	0601 To 1200
Place
Locale Reference	atc facility : mmex
State Reference	FO
Altitude	msl bound lower : 35000 msl bound upper : 37000
Environment
Flight Conditions	VMC
Light	Daylight
Aircraft 1
Controlling Facilities	artcc : mmex artcc : zid
Operator	common carrier : air carrier
Make Model Name	Medium Large Transport, Low Wing, 2 Turbojet Eng
Navigation In Use	Other Other
Flight Phase	climbout : intermediate altitude
Flight Plan	IFR
Person 1
Affiliation	company : air carrier
Function	flight crew : first officer
Qualification	pilot : instrument pilot : atp pilot : commercial pilot : flight engineer
Experience	flight time last 90 days : 200 flight time total : 2870 flight time type : 98
ASRS Report	164295
Person 2
Affiliation	company : air carrier
Function	flight crew : captain oversight : pic
Qualification	pilot : atp
Events
Anomaly	altitude deviation : overshoot
Independent Detector	other controllera
Resolutory Action	none taken : detected after the fact
Consequence	Other
Supplementary
Primary Problem	Ambiguous
Air Traffic Incident	other

Narrative:

Cleared to FL370 by mexico city clearance delivery. The clearance was not modified to our knowledge, so we climbed to FL370. After reaching FL370, center (mexico I believe) asked us to say our altitude. We told them FL370. They asked us why we went to FL370 instead of FL350. We explained that FL370 was our assigned altitude. Controller expressed no concern and did not change our altitude. I believe the controller may have wanted to assign us FL350 but didn't. Communications down there are always interesting in any event.

Original NASA ASRS Text

Title: POSSIBLE ALT OVERSHOOT IN CLIMB FOR ACR MLG IN MEXICO.

Narrative: CLRED TO FL370 BY MEXICO CITY CLRNC DELIVERY. THE CLRNC WAS NOT MODIFIED TO OUR KNOWLEDGE, SO WE CLBED TO FL370. AFTER REACHING FL370, CTR (MEXICO I BELIEVE) ASKED US TO SAY OUR ALT. WE TOLD THEM FL370. THEY ASKED US WHY WE WENT TO FL370 INSTEAD OF FL350. WE EXPLAINED THAT FL370 WAS OUR ASSIGNED ALT. CTLR EXPRESSED NO CONCERN AND DID NOT CHANGE OUR ALT. I BELIEVE THE CTLR MAY HAVE WANTED TO ASSIGN US FL350 BUT DIDN'T. COMS DOWN THERE ARE ALWAYS INTERESTING IN ANY EVENT.

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.