Mlt X had less than standard separation from air carrier Y. System error.

Attributes
ACN	135671
Time
Date	199002
Day	Sun
Local Time Of Day	0601 To 1200
Place
Locale Reference	atc facility : dqn
State Reference	OH
Altitude	msl bound lower : 22000 msl bound upper : 23000
Environment
Light	Daylight
Aircraft 1
Controlling Facilities	artcc : zid tower : bos
Operator	other
Make Model Name	Military Transport
Flight Phase	climbout : intermediate altitude
Route In Use	enroute : direct
Flight Plan	IFR
Aircraft 2
Operator	common carrier : air carrier
Make Model Name	Medium Large Transport, Low Wing, 2 Turbojet Eng
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 non radar : 3 controller radar : 1
ASRS Report	135671
Person 2
Affiliation	government : military
Function	flight crew : captain oversight : pic
Qualification	pilot : military
Events
Anomaly	altitude deviation : overshoot conflict : airborne less severe non adherence : required legal separation non adherence : published procedure
Independent Detector	other other : unspecified atc
Resolutory Action	none taken : unable
Consequence	faa : investigated faa : reviewed incident with flight crew
Miss Distance	horizontal : 21000 vertical : 100
Supplementary
Primary Problem	ATC Human Performance
Air Traffic Incident	Operational Error

Narrative:

Sectors combined (rod, ltc, cmh, zzv). Monitoring 5 VHF and UHF frequencys that were in use. Continuous frequency congestion, not to mention frequencys are inadequate and very unreliable. Equipment (frequencys) in use quality is very suspect. Mlt X readback sounded like FL220, and I believed it to be FL220. Sector tapes could not support me because of poor quality and somewhat garbled readback. Mlt X issued climb clearance to FL220. Air carrier Y wbound FL230. Traffic was called for mlt X '6 O'clock 3 mi FL230 higher in a moment.' no response from mlt X. Mlt X climbed to FL230 separation was lost. Mlt X claimed FL230 was assigned altitude. Mlt X readback on initial call-up when given clearance to FL220 was somewhat garbled, however, I understood FL220.

Original NASA ASRS Text

Title: MLT X HAD LESS THAN STANDARD SEPARATION FROM ACR Y. SYSTEM ERROR.

Narrative: SECTORS COMBINED (ROD, LTC, CMH, ZZV). MONITORING 5 VHF AND UHF FREQS THAT WERE IN USE. CONTINUOUS FREQ CONGESTION, NOT TO MENTION FREQS ARE INADEQUATE AND VERY UNRELIABLE. EQUIPMENT (FREQS) IN USE QUALITY IS VERY SUSPECT. MLT X READBACK SOUNDED LIKE FL220, AND I BELIEVED IT TO BE FL220. SECTOR TAPES COULD NOT SUPPORT ME BECAUSE OF POOR QUALITY AND SOMEWHAT GARBLED READBACK. MLT X ISSUED CLIMB CLRNC TO FL220. ACR Y WBOUND FL230. TFC WAS CALLED FOR MLT X '6 O'CLOCK 3 MI FL230 HIGHER IN A MOMENT.' NO RESPONSE FROM MLT X. MLT X CLIMBED TO FL230 SEPARATION WAS LOST. MLT X CLAIMED FL230 WAS ASSIGNED ALT. MLT X READBACK ON INITIAL CALL-UP WHEN GIVEN CLRNC TO FL220 WAS SOMEWHAT GARBLED, HOWEVER, I UNDERSTOOD FL220.

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.