G4 descent through occupied altitude had less than standard separation form BE30. System error.

Attributes
ACN	263981
Time
Date	199402
Day	Thu
Local Time Of Day	0601 To 1200
Place
Locale Reference	atc facility : ard
State Reference	PA
Altitude	msl bound lower : 12000 msl bound upper : 12000
Environment
Flight Conditions	Mixed
Light	Night
Aircraft 1
Operator	general aviation : corporate
Make Model Name	Gulfstream IV
Operating Under FAR Part	Part 91
Navigation In Use	Other Other
Flight Phase	descent other
Route In Use	enroute : direct enroute airway : zdc
Flight Plan	IFR
Aircraft 2
Operator	general aviation : corporate
Make Model Name	Super King Air 300
Operating Under FAR Part	Part 91
Flight Phase	cruise other
Route In Use	enroute : direct
Flight Plan	IFR
Person 1
Affiliation	government : faa
Function	controller : radar
Qualification	controller : radar
Experience	controller military : 2 controller radar : 13
ASRS Report	263981
Person 2
Affiliation	Other
Function	flight crew : captain oversight : pic
Qualification	pilot : atp
Events
Anomaly	conflict : airborne less severe non adherence : published procedure non adherence : required legal separation
Independent Detector	atc equipment other atc equipment : unspecified
Resolutory Action	none taken : detected after the fact
Consequence	faa : investigated
Miss Distance	horizontal : 18000 vertical : 500
Supplementary
Primary Problem	ATC Human Performance
Air Traffic Incident	Operational Error

Narrative:

The G4 X was at 12000 ft waiting for descent clearance to cross ard at 8000 ft. The BE30 Y was at 11000 ft waiting for clearance to cross and at 7000 ft. Add to this the fact that the G4's call sign was similar to the BE30's call sign. Throw in an extremely complicated sector, and a pilot who forgets to descend necessitating a ton of pointouts, and a near impossible descent profile required on this particular STAR and you have the recipe for this near miss. When both of these aircraft arrived at the same place at the same time with data tags overlapping, both needing a descent clearance at the same time. The aircraft on top was inadvertently descended through the other aircraft's airspace. We have been reporting to the FAA for yrs that this arrival procedure is dangerous and nearly impossible to execute given the amount of airspace needed and the actual amount allotted for this purpose. The arrs in question are the METRO3 (jets -- teb) and ARD2 (propellers -- teb).

Original NASA ASRS Text

Title: G4 DSCNT THROUGH OCCUPIED ALT HAD LTSS FORM BE30. SYS ERROR.

Narrative: THE G4 X WAS AT 12000 FT WAITING FOR DSCNT CLRNC TO CROSS ARD AT 8000 FT. THE BE30 Y WAS AT 11000 FT WAITING FOR CLRNC TO CROSS AND AT 7000 FT. ADD TO THIS THE FACT THAT THE G4'S CALL SIGN WAS SIMILAR TO THE BE30'S CALL SIGN. THROW IN AN EXTREMELY COMPLICATED SECTOR, AND A PLT WHO FORGETS TO DSND NECESSITATING A TON OF POINTOUTS, AND A NEAR IMPOSSIBLE DSCNT PROFILE REQUIRED ON THIS PARTICULAR STAR AND YOU HAVE THE RECIPE FOR THIS NEAR MISS. WHEN BOTH OF THESE ACFT ARRIVED AT THE SAME PLACE AT THE SAME TIME WITH DATA TAGS OVERLAPPING, BOTH NEEDING A DSCNT CLRNC AT THE SAME TIME. THE ACFT ON TOP WAS INADVERTENTLY DSNDED THROUGH THE OTHER ACFT'S AIRSPACE. WE HAVE BEEN RPTING TO THE FAA FOR YRS THAT THIS ARR PROC IS DANGEROUS AND NEARLY IMPOSSIBLE TO EXECUTE GIVEN THE AMOUNT OF AIRSPACE NEEDED AND THE ACTUAL AMOUNT ALLOTTED FOR THIS PURPOSE. THE ARRS IN QUESTION ARE THE METRO3 (JETS -- TEB) AND ARD2 (PROPS -- TEB).

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.