Communications dead spot causes misunderstood clearance leading to altitude deviation.

Attributes
ACN	234923
Time
Date	199302
Day	Sat
Local Time Of Day	1201 To 1800
Place
Locale Reference	atc facility : lrp
State Reference	PA
Altitude	msl bound lower : 9000 msl bound upper : 10000
Environment
Flight Conditions	VMC
Light	Daylight
Aircraft 1
Controlling Facilities	tower : cmi
Operator	common carrier : air carrier
Make Model Name	Light Transport, Low Wing, 2 Turboprop Eng
Flight Phase	cruise other descent other
Route In Use	enroute airway : v143
Flight Plan	IFR
Person 1
Affiliation	company : air carrier
Function	flight crew : captain oversight : pic
Qualification	pilot : cfi pilot : atp
Experience	flight time last 90 days : 280 flight time total : 7000 flight time type : 2800
ASRS Report	234923
Person 2
Affiliation	company : air carrier
Function	flight crew : first officer
Qualification	pilot : commercial pilot : instrument
Events
Anomaly	altitude deviation : overshoot non adherence : clearance
Independent Detector	other controllera
Resolutory Action	flight crew : returned to intended course or assigned course other
Consequence	Other
Supplementary
Primary Problem	Flight Crew Human Performance
Air Traffic Incident	Pilot Deviation
Situations
ATC Facility	other physical facility

Narrative:

Problem regularly arises with communication with center in same position regularly. Center clears flts to lower altitudes in anticipation of handoff to iad approach (126.1) but then can't hear or believe reply. Particular frequency was 132.5. One particular event occurred after passing ioane intersection swbound on V143, frequency became quiet. I became suspicious, only heard aircraft replying but not center. Asked for radio check. No reply. Turned up squelch. Barely heard center say 'xyz 9000 ft cross robrt.' we replied. No response. We descended to 9000 ft then started hearing center call repeatedly, with anger, and we still replied but were not heard. Contact restored just before 'hyper' told us that we were supposed to be at 10000 ft, not 9000 ft. Bad communication in a specific area a recurring problem.

Original NASA ASRS Text

Title: COMS DEAD SPOT CAUSES MISUNDERSTOOD CLRNC LEADING TO ALTDEV.

Narrative: PROB REGULARLY ARISES WITH COM WITH CTR IN SAME POS REGULARLY. CTR CLRS FLTS TO LOWER ALTS IN ANTICIPATION OF HDOF TO IAD APCH (126.1) BUT THEN CAN'T HEAR OR BELIEVE REPLY. PARTICULAR FREQ WAS 132.5. ONE PARTICULAR EVENT OCCURRED AFTER PASSING IOANE INTXN SWBOUND ON V143, FREQ BECAME QUIET. I BECAME SUSPICIOUS, ONLY HEARD ACFT REPLYING BUT NOT CTR. ASKED FOR RADIO CHK. NO REPLY. TURNED UP SQUELCH. BARELY HEARD CTR SAY 'XYZ 9000 FT CROSS ROBRT.' WE REPLIED. NO RESPONSE. WE DSNDED TO 9000 FT THEN STARTED HEARING CTR CALL REPEATEDLY, WITH ANGER, AND WE STILL REPLIED BUT WERE NOT HEARD. CONTACT RESTORED JUST BEFORE 'HYPER' TOLD US THAT WE WERE SUPPOSED TO BE AT 10000 FT, NOT 9000 FT. BAD COM IN A SPECIFIC AREA A RECURRING PROB.

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.