37000 Feet | Browse and search NASA's Aviation Safety Reporting System |
|
Attributes | |
ACN | 241038 |
Time | |
Date | 199305 |
Day | Mon |
Local Time Of Day | 1201 To 1800 |
Place | |
Locale Reference | atc facility : dqo |
State Reference | PA |
Altitude | msl bound lower : 15000 msl bound upper : 16100 |
Environment | |
Flight Conditions | VMC |
Light | Daylight |
Aircraft 1 | |
Controlling Facilities | artcc : zdc tower : ord |
Operator | common carrier : air carrier |
Make Model Name | Medium Large Transport, Low Wing, 2 Turbojet Eng |
Navigation In Use | Other Other |
Flight Phase | cruise other |
Route In Use | arrival other |
Flight Plan | IFR |
Aircraft 2 | |
Make Model Name | Any Unknown or Unlisted Aircraft Manufacturer |
Flight Phase | cruise other |
Flight Plan | VFR |
Person 1 | |
Affiliation | company : air carrier |
Function | flight crew : first officer |
Qualification | pilot : atp |
Experience | flight time last 90 days : 200 flight time total : 15000 flight time type : 3000 |
ASRS Report | 241038 |
Person 2 | |
Affiliation | company : air carrier |
Function | flight crew : captain oversight : pic |
Qualification | pilot : atp |
Events | |
Anomaly | altitude deviation : excursion from assigned altitude conflict : airborne less severe non adherence : clearance other anomaly other |
Independent Detector | aircraft equipment other aircraft equipment : unspecified |
Resolutory Action | flight crew : took evasive action |
Consequence | faa : reviewed incident with flight crew |
Miss Distance | horizontal : 0 vertical : 1500 |
Supplementary | |
Primary Problem | Flight Crew Human Performance |
Air Traffic Incident | other |
Narrative:
Level at 15000 ft, an aircraft appeared on the TCASII scope at 18 NM (20 NM scope selected). Position was 12 O'clock and altitude indicated -4. Both pilots tried to spot the aircraft but visual contact was never attained. Captain attempted to call center but frequency was congested and when he did get through, there was no response. At approximately 8 NM, TCASII commanded 'climb, climb, climb.' autoplt was immediately disengaged and climb initiated at 2200 FPM in response to ivi cues. ZDC was notified of climb. At approximately 16000 ft the TCASII command changed to 'monitor vertical speed.' aircraft was leveled at 16100 ft. 'Clear of conflict' was quickly announced and aircraft was returned to 15000 ft. Intruder aircraft was never sighted. Controller was busy and said aircraft was VFR and he had planned to call him out. In a later phone conversation with a ZDC supervisor, the supervisor stated, 'the TCASII shouldn't have done that. The aircraft was VFR.' this appears to be a situation where control of IFR and VFR aircraft was acceptable, but greater controller understanding of TCASII parameters could have avoided the requirement for the crew to leave their assigned altitude in response to a TCASII RA.
Original NASA ASRS Text
Title: ACR AT CRUISE HAS TCASII RA TO CLB. DOES SO.
Narrative: LEVEL AT 15000 FT, AN ACFT APPEARED ON THE TCASII SCOPE AT 18 NM (20 NM SCOPE SELECTED). POS WAS 12 O'CLOCK AND ALT INDICATED -4. BOTH PLTS TRIED TO SPOT THE ACFT BUT VISUAL CONTACT WAS NEVER ATTAINED. CAPT ATTEMPTED TO CALL CTR BUT FREQ WAS CONGESTED AND WHEN HE DID GET THROUGH, THERE WAS NO RESPONSE. AT APPROX 8 NM, TCASII COMMANDED 'CLB, CLB, CLB.' AUTOPLT WAS IMMEDIATELY DISENGAGED AND CLB INITIATED AT 2200 FPM IN RESPONSE TO IVI CUES. ZDC WAS NOTIFIED OF CLB. AT APPROX 16000 FT THE TCASII COMMAND CHANGED TO 'MONITOR VERT SPD.' ACFT WAS LEVELED AT 16100 FT. 'CLR OF CONFLICT' WAS QUICKLY ANNOUNCED AND ACFT WAS RETURNED TO 15000 FT. INTRUDER ACFT WAS NEVER SIGHTED. CTLR WAS BUSY AND SAID ACFT WAS VFR AND HE HAD PLANNED TO CALL HIM OUT. IN A LATER PHONE CONVERSATION WITH A ZDC SUPVR, THE SUPVR STATED, 'THE TCASII SHOULDN'T HAVE DONE THAT. THE ACFT WAS VFR.' THIS APPEARS TO BE A SIT WHERE CTL OF IFR AND VFR ACFT WAS ACCEPTABLE, BUT GREATER CTLR UNDERSTANDING OF TCASII PARAMETERS COULD HAVE AVOIDED THE REQUIREMENT FOR THE CREW TO LEAVE THEIR ASSIGNED ALT IN RESPONSE TO A TCASII RA.
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.