Altitude deviation altitude excursion during flight crew response to TCASII RA. Software 6 point 4A ...

Attributes
ACN	283960
Time
Date	199409
Day	Thu
Local Time Of Day	1201 To 1800
Place
Locale Reference	atc facility : gve
State Reference	VA
Altitude	msl bound lower : 25300 msl bound upper : 26000
Environment
Flight Conditions	Mixed
Light	Daylight
Aircraft 1
Controlling Facilities	artcc : zdc tower : wjf
Operator	general aviation : corporate
Make Model Name	Any Unknown or Unlisted Aircraft Manufacturer
Operating Under FAR Part	Part 91
Navigation In Use	Other Other
Flight Phase	cruise other descent other
Flight Plan	IFR
Aircraft 2
Operator	common carrier : air carrier
Make Model Name	Any Unknown or Unlisted Aircraft Manufacturer
Operating Under FAR Part	Part 121
Flight Phase	descent other
Flight Plan	IFR
Person 1
Affiliation	Other
Function	flight crew : first officer
Qualification	pilot : atp
Experience	flight time last 90 days : 30 flight time total : 3800 flight time type : 100
ASRS Report	283960
Person 2
Affiliation	Other
Function	flight crew : captain oversight : pic
Qualification	pilot : atp
Experience	flight time last 90 days : 90 flight time total : 8500 flight time type : 900
ASRS Report	283827
Events
Anomaly	aircraft equipment problem : less severe altitude deviation : overshoot altitude deviation : excursion from assigned altitude non adherence : clearance other anomaly other
Independent Detector	aircraft equipment other aircraft equipment : unspecified other controllera
Resolutory Action	flight crew : became reoriented flight crew : returned to intended course or assigned course flight crew : took evasive action
Consequence	Other
Miss Distance	horizontal : 0 vertical : 1700
Supplementary
Primary Problem	Aircraft
Air Traffic Incident	Pilot Deviation

Narrative:

After approximately 20 mins from teterboro at interim FL260, we encountered a right converter fail. While going through the checklist to determine our course of action we received a blue then amber TA which changed into a red RA calling for an immediate descent at a rate of 1700 FPM. I began the descent and the first officer called center advising them of the deviation because of an RA. Once we were clear of traffic I began climbing back to FL260. The altitude was overshot to 26320 ft but immediately returned to FL260. Once established we advised ATC that we were level at FL260. Center then said that he was trying to advise us of descending traffic to FL270. We never received the call. The ensuing altitude overshoot occurred when 2 problems were being handled at the same time -- the RA and the failed converter. Once altitude was re- established the remaining portion of the trip was uneventful. Supplemental information from acn 283829: PF immediately responded to advisory and descended to 25300 ft before clear of conflict. As soon as we initiated descent I informed ATC we were responding to an RA. ATC responded they were about to warn us of the descending traffic that created the conflict. That traffic was cleared in his descent to FL270. The other traffic did, in fact, level properly at FL270. Our aircraft TCASII does have the latest updated software to help reduce the number of advisories given. This case is another example of the 'growing pains' of the TCASII equipment. There are just too many variables for the TCASII to be able to always give advisories that are legitimate, when the present equipment has no knowledge of what altitude other aircraft are cleared to be at. If the equipment software cannot be improved further, then controllers will have to be more vigilant in issuing climb and descent clrncs, and pilots will have to be ever more vigilant to slow down rates of climb and descent when nearing altitudes they are cleared to.

Original NASA ASRS Text

Title: ALTDEV ALT EXCURSION DURING FLC RESPONSE TO TCASII RA. SOFTWARE 6 POINT 4A FAILS TO PREVENT EVASIVE ACTION DSCNT.

Narrative: AFTER APPROX 20 MINS FROM TETERBORO AT INTERIM FL260, WE ENCOUNTERED A R CONVERTER FAIL. WHILE GOING THROUGH THE CHKLIST TO DETERMINE OUR COURSE OF ACTION WE RECEIVED A BLUE THEN AMBER TA WHICH CHANGED INTO A RED RA CALLING FOR AN IMMEDIATE DSCNT AT A RATE OF 1700 FPM. I BEGAN THE DSCNT AND THE FO CALLED CTR ADVISING THEM OF THE DEV BECAUSE OF AN RA. ONCE WE WERE CLR OF TFC I BEGAN CLBING BACK TO FL260. THE ALT WAS OVERSHOT TO 26320 FT BUT IMMEDIATELY RETURNED TO FL260. ONCE ESTABLISHED WE ADVISED ATC THAT WE WERE LEVEL AT FL260. CTR THEN SAID THAT HE WAS TRYING TO ADVISE US OF DSNDING TFC TO FL270. WE NEVER RECEIVED THE CALL. THE ENSUING ALT OVERSHOOT OCCURRED WHEN 2 PROBS WERE BEING HANDLED AT THE SAME TIME -- THE RA AND THE FAILED CONVERTER. ONCE ALT WAS RE- ESTABLISHED THE REMAINING PORTION OF THE TRIP WAS UNEVENTFUL. SUPPLEMENTAL INFO FROM ACN 283829: PF IMMEDIATELY RESPONDED TO ADVISORY AND DSNDED TO 25300 FT BEFORE CLR OF CONFLICT. AS SOON AS WE INITIATED DSCNT I INFORMED ATC WE WERE RESPONDING TO AN RA. ATC RESPONDED THEY WERE ABOUT TO WARN US OF THE DSNDING TFC THAT CREATED THE CONFLICT. THAT TFC WAS CLRED IN HIS DSCNT TO FL270. THE OTHER TFC DID, IN FACT, LEVEL PROPERLY AT FL270. OUR ACFT TCASII DOES HAVE THE LATEST UPDATED SOFTWARE TO HELP REDUCE THE NUMBER OF ADVISORIES GIVEN. THIS CASE IS ANOTHER EXAMPLE OF THE 'GROWING PAINS' OF THE TCASII EQUIP. THERE ARE JUST TOO MANY VARIABLES FOR THE TCASII TO BE ABLE TO ALWAYS GIVE ADVISORIES THAT ARE LEGITIMATE, WHEN THE PRESENT EQUIP HAS NO KNOWLEDGE OF WHAT ALT OTHER ACFT ARE CLRED TO BE AT. IF THE EQUIP SOFTWARE CANNOT BE IMPROVED FURTHER, THEN CTLRS WILL HAVE TO BE MORE VIGILANT IN ISSUING CLB AND DSCNT CLRNCS, AND PLTS WILL HAVE TO BE EVER MORE VIGILANT TO SLOW DOWN RATES OF CLB AND DSCNT WHEN NEARING ALTS THEY ARE CLRED TO.

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.

Altitude deviation altitude excursion during flight crew response to TCASII RA. Software 6 point 4A fails to prevent evasive action descent.