Air carrier medium large transport descended below assigned altitude due clearance interpretation.

Attributes
ACN	88612
Time
Date	198806
Day	Fri
Local Time Of Day	1201 To 1800
Place
Locale Reference	atc facility : zhn
State Reference	HI
Altitude	msl bound lower : 3000 msl bound upper : 13000
Environment
Flight Conditions	VMC
Light	Daylight
Aircraft 1
Controlling Facilities	artcc : zhn tower : sbp
Operator	common carrier : air carrier
Make Model Name	Medium Large Transport
Flight Phase	descent other
Flight Plan	IFR
Person 1
Affiliation	company : air carrier
Function	flight crew : captain
Qualification	pilot : atp
Experience	flight time total : 6000
ASRS Report	88612
Person 2
Affiliation	company : air carrier
Function	flight crew : first officer
Qualification	pilot : atp
Experience	flight time last 90 days : 105 flight time total : 5000 flight time type : 600
ASRS Report	88491
Events
Anomaly	altitude deviation : overshoot non adherence : clearance
Independent Detector	other controllera
Resolutory Action	controller : issued new clearance
Consequence	faa : reviewed incident with flight crew
Supplementary
Primary Problem	Ambiguous
Air Traffic Incident	other

Narrative:

We we on a normal IFR flight from hnl to koa at FL190. We were on center frequency and cleared direct to koa VOR. At approximately 55 DME the controller gave us a clearance which sounded like 'pilots discretion, descend and maintain 3000'.' the copilot read back 3000 and told the controller: 'we are leaving FL190 for three thousand.' as we passed through 12,700' the controller said: 'say altitude.' copilot gave: '12,700 for 3000'. Controller: 'expedite to 3000'.' 'I told you to maintain 13000'.' that was all that was said about it until we got back to hnl where we had a message to call the hnl center chief. I spoke to him on the phone and he said he would not follow up with paperwork for busting the altitude. I think he elected not to push it because the controller accepted an incorrect (if it was actually 13000' in the original descent clearance) readback.

Original NASA ASRS Text

Title: ACR MLG DESCENDED BELOW ASSIGNED ALT DUE CLRNC INTERPRETATION.

Narrative: WE WE ON A NORMAL IFR FLT FROM HNL TO KOA AT FL190. WE WERE ON CENTER FREQ AND CLRED DIRECT TO KOA VOR. AT APPROX 55 DME THE CTLR GAVE US A CLRNC WHICH SOUNDED LIKE 'PLTS DISCRETION, DESCEND AND MAINTAIN 3000'.' THE COPLT READ BACK 3000 AND TOLD THE CTLR: 'WE ARE LEAVING FL190 FOR THREE THOUSAND.' AS WE PASSED THROUGH 12,700' THE CTLR SAID: 'SAY ALT.' COPLT GAVE: '12,700 FOR 3000'. CTLR: 'EXPEDITE TO 3000'.' 'I TOLD YOU TO MAINTAIN 13000'.' THAT WAS ALL THAT WAS SAID ABOUT IT UNTIL WE GOT BACK TO HNL WHERE WE HAD A MESSAGE TO CALL THE HNL CENTER CHIEF. I SPOKE TO HIM ON THE PHONE AND HE SAID HE WOULD NOT FOLLOW UP WITH PAPERWORK FOR BUSTING THE ALT. I THINK HE ELECTED NOT TO PUSH IT BECAUSE THE CTLR ACCEPTED AN INCORRECT (IF IT WAS ACTUALLY 13000' IN THE ORIGINAL DESCENT CLRNC) READBACK.

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.