United states based air carrier widebody transport performs an unauthorized takeoff when a phraseology and language barrier problem induces crew to believe that they had obtained a clearance takeoff.

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Attributes
ACN	193679
Time
Date	199111
Day	Wed
Local Time Of Day	0601 To 1200
Place
Locale Reference	airport : mad
State Reference	FO
Altitude	agl bound lower : 0 agl bound upper : 0
Environment
Flight Conditions	VMC
Light	Daylight
Aircraft 1
Operator	common carrier : air carrier
Make Model Name	Widebody, Low Wing, 2 Turbojet Eng
Navigation In Use	Other Other
Flight Phase	climbout : takeoff ground : holding
Flight Plan	IFR
Person 1
Affiliation	company : air carrier
Function	flight crew : first officer other personnel other
Qualification	pilot : atp pilot : flight engineer
Experience	flight time last 90 days : 150 flight time total : 6500 flight time type : 1100
ASRS Report	193679
Person 2
Affiliation	company : air carrier
Function	flight crew : captain oversight : pic
Qualification	pilot : atp
ASRS Report	194235
Events
Anomaly	incursion : runway non adherence : clearance other anomaly other
Independent Detector	other controllera
Resolutory Action	none taken : detected after the fact
Consequence	Other
Supplementary
Primary Problem	Flight Crew Human Performance
Air Traffic Incident	Pilot Deviation other
Situations
ATC Facility	procedure or policy : unspecified

Narrative:

Tower called aircraft after we were airborne and said we had taken off without clearance. Tower controller said there was 'no problem' and handed us over to departure. Captain said we thought we were cleared for takeoff, all 3 pilots in cockpit concurred. The following sequence of events and transmissions will explain this incident: tower cleared to 'XXX line up runway 1.' as we turned onto runway the controller said in broken english, 'XXX cleared to FL100 on takeoff.' all 3 pilots construed this as cleared for takeoff. (Normally a change in departure altitudes is preceded with 'after departure climb and maintain flxxx'.) there was no conflict with other arriving or departing traffic but this situation once again emphasizes the importance of standardized transmissions between ATC and pilots. The lesson learned was never assume anything when ATC communications are broken or garbled.

Original NASA ASRS Text

Title: UNITED STATES BASED ACR WDB PERFORMS AN UNAUTHORIZED TKOF WHEN A PHRASEOLOGY AND LANGUAGE BARRIER PROBLEM INDUCES CREW TO BELIEVE THAT THEY HAD OBTAINED A CLRNC TKOF.

Narrative: TWR CALLED ACFT AFTER WE WERE AIRBORNE AND SAID WE HAD TAKEN OFF WITHOUT CLRNC. TWR CTLR SAID THERE WAS 'NO PROBLEM' AND HANDED US OVER TO DEP. CAPT SAID WE THOUGHT WE WERE CLRED FOR TKOF, ALL 3 PLTS IN COCKPIT CONCURRED. THE FOLLOWING SEQUENCE OF EVENTS AND TRANSMISSIONS WILL EXPLAIN THIS INCIDENT: TWR CLRED TO 'XXX LINE UP RWY 1.' AS WE TURNED ONTO RWY THE CTLR SAID IN BROKEN ENGLISH, 'XXX CLRED TO FL100 ON TKOF.' ALL 3 PLTS CONSTRUED THIS AS CLRED FOR TKOF. (NORMALLY A CHANGE IN DEP ALTS IS PRECEDED WITH 'AFTER DEP CLB AND MAINTAIN FLXXX'.) THERE WAS NO CONFLICT WITH OTHER ARRIVING OR DEPARTING TFC BUT THIS SITUATION ONCE AGAIN EMPHASIZES THE IMPORTANCE OF STANDARDIZED TRANSMISSIONS BTWN ATC AND PLTS. THE LESSON LEARNED WAS NEVER ASSUME ANYTHING WHEN ATC COMS ARE BROKEN OR GARBLED.

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.