An arriving widebody transport in IMC reacts to TCASII RA, traffic passes about 400 ft over the top.

Attributes
ACN	224451
Time
Date	199210
Day	Sat
Local Time Of Day	0601 To 1200
Place
Locale Reference	airport : muc
State Reference	FO
Altitude	msl bound lower : 9700 msl bound upper : 10000
Environment
Flight Conditions	IMC
Light	Daylight
Aircraft 1
Controlling Facilities	tracon : muc
Operator	common carrier : air carrier
Make Model Name	Widebody, Low Wing, 3 Turbojet Eng
Flight Phase	descent other
Route In Use	arrival other
Flight Plan	IFR
Aircraft 2
Make Model Name	Any Unknown or Unlisted Aircraft Manufacturer
Person 1
Affiliation	company : air carrier
Function	flight crew : first officer
Qualification	pilot : atp
Experience	controller military : 7 controller radar : 15 flight time last 90 days : 110 flight time total : 9999 flight time type : 110
ASRS Report	224451
Person 2
Affiliation	company : air carrier
Function	flight crew : captain oversight : pic
Qualification	pilot : atp
Events
Anomaly	conflict : nmac non adherence : far
Independent Detector	aircraft equipment other aircraft equipment : unspecified other flight crewa
Resolutory Action	none taken : unable
Consequence	Other
Miss Distance	horizontal : 0 vertical : 400
Supplementary
Primary Problem	ATC Human Performance
Air Traffic Incident	other

Narrative:

International flight 40 NM west of muc (munich), germany, descending through 10000 ft MSL. We were notified by muc approach of traffic 12 O'clock, 7 mi. TCASII confirmed the traffic. Continuing our descent we received an RA about 3-4 NM from the other aircraft. Our altitude was about 9700 ft MSL, starting our level off to slow to 250 KTS. The TCASII directed us to steepen/increase our descent in excess of 2000 FPM, which we did, and as the other aircraft passed overhead, our TCASII showed his altitude. He passed approximately 400 ft directly over us. According to our TCASII (we were IMC). Muc approach only called us 1 time, when our traffic was 7 mi in front of us. It was very early in the am for us. We had flown all night and of course tired. I was flying the aircraft. Being tired it took a couple of extra seconds to interpret the TCASII symbology, and vsi instructions. I think muc erred, and TCASII prevented an accident. I have 1 other question. Is the separation criteria in germany/europe different than in the united states of america for descent below 10000 ft MSL or in europe FL100? Or, did TCASII err?

Original NASA ASRS Text

Title: AN ARRIVING WDB IN IMC REACTS TO TCASII RA, TFC PASSES ABOUT 400 FT OVER THE TOP.

Narrative: INTL FLT 40 NM W OF MUC (MUNICH), GERMANY, DSNDING THROUGH 10000 FT MSL. WE WERE NOTIFIED BY MUC APCH OF TFC 12 O'CLOCK, 7 MI. TCASII CONFIRMED THE TFC. CONTINUING OUR DSCNT WE RECEIVED AN RA ABOUT 3-4 NM FROM THE OTHER ACFT. OUR ALT WAS ABOUT 9700 FT MSL, STARTING OUR LEVEL OFF TO SLOW TO 250 KTS. THE TCASII DIRECTED US TO STEEPEN/INCREASE OUR DSCNT IN EXCESS OF 2000 FPM, WHICH WE DID, AND AS THE OTHER ACFT PASSED OVERHEAD, OUR TCASII SHOWED HIS ALT. HE PASSED APPROX 400 FT DIRECTLY OVER US. ACCORDING TO OUR TCASII (WE WERE IMC). MUC APCH ONLY CALLED US 1 TIME, WHEN OUR TFC WAS 7 MI IN FRONT OF US. IT WAS VERY EARLY IN THE AM FOR US. WE HAD FLOWN ALL NIGHT AND OF COURSE TIRED. I WAS FLYING THE ACFT. BEING TIRED IT TOOK A COUPLE OF EXTRA SECONDS TO INTERPRET THE TCASII SYMBOLOGY, AND VSI INSTRUCTIONS. I THINK MUC ERRED, AND TCASII PREVENTED AN ACCIDENT. I HAVE 1 OTHER QUESTION. IS THE SEPARATION CRITERIA IN GERMANY/EUROPE DIFFERENT THAN IN THE UNITED STATES OF AMERICA FOR DSCNT BELOW 10000 FT MSL OR IN EUROPE FL100? OR, DID TCASII ERR?

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.