Narrative:

After broadcasting our intentions, we taxied on to runway to back-taxi to other end (34). There was another aircraft that had taken off that was airborne about 2/3 the way down the runway 500-600 ft above us. There was no evasive action required at all!! I called on frequency 6-7 times before the aircraft responded. He said that he transmitted his takeoff. We did not hear this and we had radios on through start of the engine in the blocks, flag out, and taxi. The other aircraft also said he did not hear us announce our intentions to back taxi. I don't know if there is a dead spot when transmitting from one end to the other. I know that we made a call to alert the other aircraft in the area. We also both checked each way visually and verbally called it clear both ways. The runway has a small over hill slope plus trees and a small city at the south end. Plus my sun visor was hanging down, which may have blocked seeing the aircraft also the sky was blue and the aircraft that took off had a dark underside (maybe oil exhaust) with light colored wings. I did not notice a landing light on. As I stated I did call the other aircraft and he and I both agreed no evasive action was needed with his nose high, I don't think we saw us. My copilot and I have no solution, but we will make more than one call from now on.

Google
 

Original NASA ASRS Text

Title: FLC OF AN LTT ACR ACFT TAXIED ONTO A NON CTLED ARPT RWY THAT WAS IN USE RESULTING IN THE OTHER ACFT TAKING OFF OVER THE RPTR'S ACFT.

Narrative: AFTER BROADCASTING OUR INTENTIONS, WE TAXIED ON TO RWY TO BACK-TAXI TO OTHER END (34). THERE WAS ANOTHER ACFT THAT HAD TAKEN OFF THAT WAS AIRBORNE ABOUT 2/3 THE WAY DOWN THE RWY 500-600 FT ABOVE US. THERE WAS NO EVASIVE ACTION REQUIRED AT ALL!! I CALLED ON FREQ 6-7 TIMES BEFORE THE ACFT RESPONDED. HE SAID THAT HE XMITTED HIS TKOF. WE DID NOT HEAR THIS AND WE HAD RADIOS ON THROUGH START OF THE ENG IN THE BLOCKS, FLAG OUT, AND TAXI. THE OTHER ACFT ALSO SAID HE DID NOT HEAR US ANNOUNCE OUR INTENTIONS TO BACK TAXI. I DON'T KNOW IF THERE IS A DEAD SPOT WHEN XMITTING FROM ONE END TO THE OTHER. I KNOW THAT WE MADE A CALL TO ALERT THE OTHER ACFT IN THE AREA. WE ALSO BOTH CHKED EACH WAY VISUALLY AND VERBALLY CALLED IT CLR BOTH WAYS. THE RWY HAS A SMALL OVER HILL SLOPE PLUS TREES AND A SMALL CITY AT THE S END. PLUS MY SUN VISOR WAS HANGING DOWN, WHICH MAY HAVE BLOCKED SEEING THE ACFT ALSO THE SKY WAS BLUE AND THE ACFT THAT TOOK OFF HAD A DARK UNDERSIDE (MAYBE OIL EXHAUST) WITH LIGHT COLORED WINGS. I DID NOT NOTICE A LNDG LIGHT ON. AS I STATED I DID CALL THE OTHER ACFT AND HE AND I BOTH AGREED NO EVASIVE ACTION WAS NEEDED WITH HIS NOSE HIGH, I DON'T THINK WE SAW US. MY COPLT AND I HAVE NO SOLUTION, BUT WE WILL MAKE MORE THAN ONE CALL FROM NOW ON.

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.