Flight crew of large transport departing panama allegedly took off without clearance.

Attributes
ACN	127690
Time
Date	198911
Day	Thu
Local Time Of Day	0601 To 1200
Place
Locale Reference	airport : mpho
State Reference	FO
Altitude	msl bound lower : 400 msl bound upper : 400
Environment
Flight Conditions	VMC
Light	Daylight
Aircraft 1
Operator	common carrier : air taxi
Make Model Name	Large Transport
Flight Phase	climbout : takeoff climbout : initial
Route In Use	enroute : on vectors
Flight Plan	IFR
Person 1
Affiliation	company : air taxi
Function	flight crew : captain oversight : pic
Qualification	pilot : atp pilot : commercial pilot : instrument
Experience	flight time last 90 days : 200 flight time total : 8000
ASRS Report	127690
Person 2
Affiliation	company : air taxi
Function	flight crew : first officer
Qualification	pilot : instrument pilot : commercial
Events
Anomaly	incursion : runway
Independent Detector	other controllera
Resolutory Action	controller : issued new clearance other
Consequence	Other
Supplementary
Primary Problem	Ambiguous
Air Traffic Incident	other

Narrative:

IFR departure clearance was given to flight at the 'hold short line' prior to runway 36 and howard AFB. We were then instructed to switch to the ct and then subsequently instructed by the ct as follows: 'cleared into position runway 36'. It then appeared to the crew and myself that the next instructions were from a different voice. Our understanding was as follows: 'the surface wind is..., you are cleared for takeoff'. (We acknowledged same and commenced takeoff.) after liftoff and passage of approximately 400' AGL, we were instructed by the ct to make rh close traffic as we had not been 'cleared' for takeoff. (We acknowledged and complied.) in light of safety to us and any local traffic whose safety might also be compromised, if there had been some misunderstanding either on our part of the ct, I believe that the ct should exercise some effort to prevent a departure on their runway by any aircraft not cleared for same.

Original NASA ASRS Text

Title: FLT CREW OF LGT DEPARTING PANAMA ALLEGEDLY TOOK OFF WITHOUT CLRNC.

Narrative: IFR DEP CLRNC WAS GIVEN TO FLT AT THE 'HOLD SHORT LINE' PRIOR TO RWY 36 AND HOWARD AFB. WE WERE THEN INSTRUCTED TO SWITCH TO THE CT AND THEN SUBSEQUENTLY INSTRUCTED BY THE CT AS FOLLOWS: 'CLRED INTO POSITION RWY 36'. IT THEN APPEARED TO THE CREW AND MYSELF THAT THE NEXT INSTRUCTIONS WERE FROM A DIFFERENT VOICE. OUR UNDERSTANDING WAS AS FOLLOWS: 'THE SURFACE WIND IS..., YOU ARE CLRED FOR TKOF'. (WE ACKNOWLEDGED SAME AND COMMENCED TKOF.) AFTER LIFTOFF AND PASSAGE OF APPROX 400' AGL, WE WERE INSTRUCTED BY THE CT TO MAKE RH CLOSE TFC AS WE HAD NOT BEEN 'CLRED' FOR TKOF. (WE ACKNOWLEDGED AND COMPLIED.) IN LIGHT OF SAFETY TO US AND ANY LCL TFC WHOSE SAFETY MIGHT ALSO BE COMPROMISED, IF THERE HAD BEEN SOME MISUNDERSTANDING EITHER ON OUR PART OF THE CT, I BELIEVE THAT THE CT SHOULD EXERCISE SOME EFFORT TO PREVENT A DEP ON THEIR RWY BY ANY ACFT NOT CLRED FOR SAME.

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.