Less than standard separation on IFR flight plan.

Attributes
ACN	105244
Time
Date	198902
Day	Thu
Local Time Of Day	1201 To 1800
Place
Locale Reference	atc facility : ase
State Reference	CO
Altitude	msl bound lower : 18000 msl bound upper : 22000
Environment
Flight Conditions	VMC
Light	Daylight
Aircraft 1
Controlling Facilities	artcc : zdv
Operator	general aviation : personal
Make Model Name	Light Transport, Low Wing, 2 Turbojet Eng
Navigation In Use	Other
Flight Phase	descent other
Route In Use	enroute : on vectors
Flight Plan	IFR
Person 1
Affiliation	Other
Function	flight crew : captain oversight : pic
Qualification	pilot : atp pilot : cfi
Experience	flight time last 90 days : 50 flight time total : 10000 flight time type : 1000
ASRS Report	105244
Person 2
Affiliation	Other
Function	flight crew : first officer
Qualification	pilot : instrument pilot : commercial
Events
Anomaly	non adherence : required legal separation other anomaly other
Independent Detector	other controllera
Resolutory Action	controller : issued new clearance
Consequence	faa : reviewed incident with flight crew
Supplementary
Primary Problem	ATC Human Performance
Air Traffic Incident	other

Narrative:

Aircraft in en route descent to FL180, passing FL220, heading 245 degrees, received call from ZDV requesting immediate turn left to 220 degrees. We complied. Center then asked why we had not responded to previous calls. We stated this was first call. Center was irritated, stating an aircraft was climbing out of aspen and we appeared to be drifting too close. We did not hear any previous calls and never saw any other aircraft. No other ATC facility had complained about us not receiving their calls. There had been complaints on garbled xmissions. Upon landing I was requested to call den ATC, which I did. From the airborne remarks received from ATC and those during the subsequent telephone conversation, I got the impression that a near miss could have occurred had I not responded with a turn. This is worrisome and somewhat puzzling. I was acting in accordance with the last received and acknowledged instructions. If ATC did feel that a subsequent lost communications had occurred, why was the other aircraft cleared into our path? Or, am I to assume that communication was also lost with that aircraft as well? If that was the case, perhaps ATC had a communications problem itself. On the subsequent return flight, no reception problems were noted. Both radios were reported to maintenance for checking.

Original NASA ASRS Text

Title: LESS THAN STANDARD SEPARATION ON IFR FLT PLAN.

Narrative: ACFT IN ENRTE DSCNT TO FL180, PASSING FL220, HDG 245 DEGS, RECEIVED CALL FROM ZDV REQUESTING IMMEDIATE TURN LEFT TO 220 DEGS. WE COMPLIED. CENTER THEN ASKED WHY WE HAD NOT RESPONDED TO PREVIOUS CALLS. WE STATED THIS WAS FIRST CALL. CENTER WAS IRRITATED, STATING AN ACFT WAS CLBING OUT OF ASPEN AND WE APPEARED TO BE DRIFTING TOO CLOSE. WE DID NOT HEAR ANY PREVIOUS CALLS AND NEVER SAW ANY OTHER ACFT. NO OTHER ATC FAC HAD COMPLAINED ABOUT US NOT RECEIVING THEIR CALLS. THERE HAD BEEN COMPLAINTS ON GARBLED XMISSIONS. UPON LNDG I WAS REQUESTED TO CALL DEN ATC, WHICH I DID. FROM THE AIRBORNE REMARKS RECEIVED FROM ATC AND THOSE DURING THE SUBSEQUENT TELEPHONE CONVERSATION, I GOT THE IMPRESSION THAT A NEAR MISS COULD HAVE OCCURRED HAD I NOT RESPONDED WITH A TURN. THIS IS WORRISOME AND SOMEWHAT PUZZLING. I WAS ACTING IN ACCORDANCE WITH THE LAST RECEIVED AND ACKNOWLEDGED INSTRUCTIONS. IF ATC DID FEEL THAT A SUBSEQUENT LOST COMS HAD OCCURRED, WHY WAS THE OTHER ACFT CLRED INTO OUR PATH? OR, AM I TO ASSUME THAT COM WAS ALSO LOST WITH THAT ACFT AS WELL? IF THAT WAS THE CASE, PERHAPS ATC HAD A COMS PROB ITSELF. ON THE SUBSEQUENT RETURN FLT, NO RECEPTION PROBS WERE NOTED. BOTH RADIOS WERE RPTED TO MAINT FOR CHKING.

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.