<< >> NASA ASRS Report 158425, September 1990

Bizjet light transport departs with known transponder malfunction, misses assigned altitude, and had less than standard separation.

Attributes
ACN	158425
Time
Date	199009
Day	Sun
Local Time Of Day	1801 To 2400
Place
Locale Reference	airport : dtw
State Reference	MI
Altitude	msl bound lower : 5500 msl bound upper : 6000
Environment
Flight Conditions	VMC
Light	Daylight
Aircraft 1
Controlling Facilities	tracon : dtw tower : ewr
Operator	common carrier : air taxi
Make Model Name	Light Transport, Low Wing, 2 Turbojet Eng
Navigation In Use	Other
Flight Phase	climbout : intermediate altitude cruise other
Route In Use	enroute : on vectors
Flight Plan	IFR
Aircraft 2
Make Model Name	Light Transport, Low Wing, 2 Turboprop Eng
Flight Phase	cruise other
Person 1
Affiliation	company : air carrier
Function	flight crew : captain oversight : pic
Qualification	pilot : atp
Experience	flight time last 90 days : 165 flight time total : 3350 flight time type : 1200
ASRS Report	158425
Person 2
Affiliation	government : faa
Function	controller : departure
Qualification	controller : radar
Events
Anomaly	aircraft equipment problem : less severe altitude deviation : overshoot conflict : airborne less severe non adherence : required legal separation
Independent Detector	other controllera
Resolutory Action	none taken : unable
Consequence	Other
Miss Distance	horizontal : 2000 vertical : 800
Supplementary
Primary Problem	Flight Crew Human Performance
Air Traffic Incident	Pilot Deviation

Narrative:

We had been having trouble, bizjet light transport X, with our transponder all day. Since then, it had been fixed at an avionics shop, but several times it was reading 3-400' higher than altimeter reported and dropping off line in transponder operation. Loss was reported 10 plus times of transponder reporting. Departing dtw, cleared to 5000', we were notified our transponder showed us at 5500', that we had traffic at 6000'. The traffic which appeared to be a light transport Y type turboprop, passed over us at what appeared to be 1000' of vertical sep or nearly that large a distance (800'). We descended 200' to 5000' on altimeter, then were cleared to 10000'.

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Original NASA ASRS Text

Title: BIZJET LTT DEPARTS WITH KNOWN TRANSPONDER MALFUNCTION, MISSES ASSIGNED ALT, AND HAD LESS THAN STANDARD SEPARATION.

Narrative: WE HAD BEEN HAVING TROUBLE, BIZJET LTT X, WITH OUR XPONDER ALL DAY. SINCE THEN, IT HAD BEEN FIXED AT AN AVIONICS SHOP, BUT SEVERAL TIMES IT WAS READING 3-400' HIGHER THAN ALTIMETER RPTED AND DROPPING OFF LINE IN XPONDER OPERATION. LOSS WAS RPTED 10 PLUS TIMES OF XPONDER RPTING. DEPARTING DTW, CLRED TO 5000', WE WERE NOTIFIED OUR XPONDER SHOWED US AT 5500', THAT WE HAD TFC AT 6000'. THE TFC WHICH APPEARED TO BE A LTT Y TYPE TURBOPROP, PASSED OVER US AT WHAT APPEARED TO BE 1000' OF VERT SEP OR NEARLY THAT LARGE A DISTANCE (800'). WE DSNDED 200' TO 5000' ON ALTIMETER, THEN WERE CLRED TO 10000'.

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.