Narrative:

Helicopter X request greenbelt route 1 landing washington VFR entry was approved and given a reporting 2 mi northeast of the airport. When the traffic reached the reporting point he was given additional clearance then told to land in the run-up block of runway 21. Traffic was holding in position on runway 36 for traffic. Departing runway 3. Traffic cleared for takeoff on runway 3, helicopter X traffic was issued to the departing air carrier Y. Helicopter X was then instructed to proceed swbnd remain west of runway 3 departing traffic. The helicopter rotated, turned sebnd towards runway 3/21. Instructions were issued to remain west of runway 3 prior to the helicopter crossing in front of the departing traffic. Horizontal sep may have been 1000'. Vertical sep was probably not more than 300'. No instructions were given to the departing fixed wing after traffic advisories were issued upon clearance. At the time of the incursion, the departure was not airborne but had maybe 2000' remaining. The pilot had 19 yrs experience flying and said he had flown into national on numerous occasions. He said it was the first time he had landed in the run-up block of 21. After receiving the instructions he believed he was east of runway 3/21 and had to cross the runway to comply. He never saw the traffic.

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Original NASA ASRS Text

Title: HELICOPTER X UNAUTH RWY CROSSING HAD LESS THAN STANDARD SEPARATION WITH ACR Y. PLTDEV.

Narrative: HELI X REQUEST GREENBELT RTE 1 LNDG WASHINGTON VFR ENTRY WAS APPROVED AND GIVEN A RPTING 2 MI NE OF THE ARPT. WHEN THE TFC REACHED THE RPTING POINT HE WAS GIVEN ADDITIONAL CLRNC THEN TOLD TO LAND IN THE RUN-UP BLOCK OF RWY 21. TFC WAS HOLDING IN POS ON RWY 36 FOR TFC. DEPARTING RWY 3. TFC CLRED FOR TKOF ON RWY 3, HELI X TFC WAS ISSUED TO THE DEPARTING ACR Y. HELI X WAS THEN INSTRUCTED TO PROCEED SWBND REMAIN W OF RWY 3 DEPARTING TFC. THE HELI ROTATED, TURNED SEBND TOWARDS RWY 3/21. INSTRUCTIONS WERE ISSUED TO REMAIN W OF RWY 3 PRIOR TO THE HELI XING IN FRONT OF THE DEPARTING TFC. HORIZ SEP MAY HAVE BEEN 1000'. VERT SEP WAS PROBABLY NOT MORE THAN 300'. NO INSTRUCTIONS WERE GIVEN TO THE DEPARTING FIXED WING AFTER TFC ADVISORIES WERE ISSUED UPON CLRNC. AT THE TIME OF THE INCURSION, THE DEP WAS NOT AIRBORNE BUT HAD MAYBE 2000' REMAINING. THE PLT HAD 19 YRS EXPERIENCE FLYING AND SAID HE HAD FLOWN INTO NATIONAL ON NUMEROUS OCCASIONS. HE SAID IT WAS THE FIRST TIME HE HAD LANDED IN THE RUN-UP BLOCK OF 21. AFTER RECEIVING THE INSTRUCTIONS HE BELIEVED HE WAS E OF RWY 3/21 AND HAD TO CROSS THE RWY TO COMPLY. HE NEVER SAW THE TFC.

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.