Flight crew of a cpr medium large transport responded to another aircraft's clearance and did not kn...

Attributes
ACN	420595
Time
Date	199811
Day	Fri
Local Time Of Day	1201 To 1800
Place
Locale Reference	atc facility : psk
State Reference	VA
Altitude	msl bound lower : 38000 msl bound upper : 39000
Environment
Flight Conditions	IMC
Light	Dusk
Aircraft 1
Controlling Facilities	artcc : zdc tracon : msy
Operator	general aviation : corporate
Make Model Name	Medium Large Transport, Low Wing, 2 Turbojet Eng
Navigation In Use	Other
Flight Phase	cruise other descent other
Route In Use	enroute airway : zdc
Flight Plan	IFR
Aircraft 2
Make Model Name	Any Unknown or Unlisted Aircraft Manufacturer
Flight Phase	descent other
Flight Plan	IFR
Person 1
Affiliation	Other
Function	flight crew : captain oversight : pic
Qualification	pilot : atp pilot : cfi pilot : flight engineer
Experience	flight time last 90 days : 120 flight time total : 10000 flight time type : 3200
ASRS Report	420595
Person 2
Affiliation	Other
Function	flight crew : first officer
Qualification	pilot : instrument pilot : commercial
Events
Anomaly	altitude deviation : excursion from assigned altitude non adherence : clearance other anomaly other
Independent Detector	other controllera
Resolutory Action	flight crew : returned to intended course or assigned course other
Consequence	Other
Miss Distance	horizontal : 60000 vertical : 1000
Supplementary
Primary Problem	ATC Human Performance
Air Traffic Incident	Pilot Deviation

Narrative:

Our aircraft was given a descent from FL390 down to FL350. We were approximately 160 NM from our destination of tri, so we began a slow descent approximately 1000 FPM. At FL380 ZDC asked our altitude and we stated FL380 descending to FL350. Immediately, ATC said 'mdt X, you were supposed to be at FL390, turn now right to heading 330 degrees.' so immediately we climbed rapidly back to FL390 and began turn to heading 330 degrees. Then ATC gave aircraft Y a turn to change heading. As we were climbing through FL385, another aircraft popped up on our TCASII screen that was not there at our lower altitude. He appeared to be at our 11 O'clock position and approximately 10 mi away level at FL370. When our heading was going through 300 degrees and altitude FL390, ATC gave us a turn back direct psk VOR heading 259 degrees. I told ATC we heard him call mdt X and I repeated mdt X descend to FL350, and he said the descent was for aircraft Y. We then asked if there would be a report filed and ATC said no, that there was not a problem. I feel very strongly that ATC just gave us (mdt X) the descent and didn't realize it until he saw the conflict on his radar screen. I do know for a fact that I did repeat mdt X cleared down to FL350 and ATC didn't respond. So part of the problem was he didn't listen carefully to the readback, if he cleared aircraft Y instead of mdt X. Also, from talking to him, I think he realized he made the mistake. I also think our TCASII had a blind spot and that is why we didn't see the other aircraft until we had climbed 500 ft. Incidentally, there was no TCASII advisories and I don't think we were close enough to have gotten one either.

Original NASA ASRS Text

Title: FLC OF A CPR MLG RESPONDED TO ANOTHER ACFT'S CLRNC AND DID NOT KNOW THAT UNTIL ARTCC RADAR CTLR INTERVENED DURING THEIR DSCNT. THEY IMMEDIATELY RETURNED TO ASSIGNED AND THE CTLR ASSIGNED VECTORS TO AVOID CONFLICTING TFC.

Narrative: OUR ACFT WAS GIVEN A DSCNT FROM FL390 DOWN TO FL350. WE WERE APPROX 160 NM FROM OUR DEST OF TRI, SO WE BEGAN A SLOW DSCNT APPROX 1000 FPM. AT FL380 ZDC ASKED OUR ALT AND WE STATED FL380 DSNDING TO FL350. IMMEDIATELY, ATC SAID 'MDT X, YOU WERE SUPPOSED TO BE AT FL390, TURN NOW R TO HDG 330 DEGS.' SO IMMEDIATELY WE CLBED RAPIDLY BACK TO FL390 AND BEGAN TURN TO HDG 330 DEGS. THEN ATC GAVE ACFT Y A TURN TO CHANGE HDG. AS WE WERE CLBING THROUGH FL385, ANOTHER ACFT POPPED UP ON OUR TCASII SCREEN THAT WAS NOT THERE AT OUR LOWER ALT. HE APPEARED TO BE AT OUR 11 O'CLOCK POS AND APPROX 10 MI AWAY LEVEL AT FL370. WHEN OUR HDG WAS GOING THROUGH 300 DEGS AND ALT FL390, ATC GAVE US A TURN BACK DIRECT PSK VOR HDG 259 DEGS. I TOLD ATC WE HEARD HIM CALL MDT X AND I REPEATED MDT X DSND TO FL350, AND HE SAID THE DSCNT WAS FOR ACFT Y. WE THEN ASKED IF THERE WOULD BE A RPT FILED AND ATC SAID NO, THAT THERE WAS NOT A PROB. I FEEL VERY STRONGLY THAT ATC JUST GAVE US (MDT X) THE DSCNT AND DIDN'T REALIZE IT UNTIL HE SAW THE CONFLICT ON HIS RADAR SCREEN. I DO KNOW FOR A FACT THAT I DID REPEAT MDT X CLRED DOWN TO FL350 AND ATC DIDN'T RESPOND. SO PART OF THE PROB WAS HE DIDN'T LISTEN CAREFULLY TO THE READBACK, IF HE CLRED ACFT Y INSTEAD OF MDT X. ALSO, FROM TALKING TO HIM, I THINK HE REALIZED HE MADE THE MISTAKE. I ALSO THINK OUR TCASII HAD A BLIND SPOT AND THAT IS WHY WE DIDN'T SEE THE OTHER ACFT UNTIL WE HAD CLBED 500 FT. INCIDENTALLY, THERE WAS NO TCASII ADVISORIES AND I DON'T THINK WE WERE CLOSE ENOUGH TO HAVE GOTTEN ONE EITHER.

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.

Flight crew of a cpr medium large transport responded to another aircraft's clearance and did not know that until ARTCC radar controller intervened during their descent. They immediately returned to assigned and the controller assigned vectors to avoid conflicting traffic.