B737-700 flight crew experiences TCAS RA on a phx SID. Feels recent air carrier policy directing 30 ...

Attributes
ACN	740031
Time
Date	200705
Local Time Of Day	1201 To 1800
Place
Locale Reference	airport : phx.airport
State Reference	AZ
Environment
Flight Conditions	VMC
Light	Daylight
Aircraft 1
Controlling Facilities	tracon : p50.tracon
Operator	common carrier : air carrier
Make Model Name	B737-700
Operating Under FAR Part	Part 121
Flight Phase	climbout : initial
Route In Use	departure sid : silow
Flight Plan	IFR
Aircraft 2
Controlling Facilities	tracon : p50.tracon
Operator	common carrier : air carrier
Make Model Name	Airbus Industrie Undifferentiated or Other Model
Operating Under FAR Part	Part 121
Flight Phase	climbout : initial
Route In Use	departure sid : stjohns
Flight Plan	IFR
Person 1
Affiliation	company : air carrier
Function	flight crew : captain oversight : pic
Experience	flight time last 90 days : 141 flight time type : 9500
ASRS Report	740031
Person 2
Affiliation	company : air carrier
Function	flight crew : first officer
Events
Anomaly	conflict : airborne critical other anomaly other
Independent Detector	aircraft equipment : tcas other flight crewa
Resolutory Action	flight crew : took precautionary avoidance action
Supplementary
Problem Areas	Environmental Factor Aircraft Chart Or Publication Company Flight Crew Human Performance
Primary Problem	Company

Narrative:

I have 2 safety concerns about our current fom procedures and TCAS RA programming. The event was an RA generated in our turn to the north on the departure from phx. Preceding us was another carrier. Takeoff spacing was minimal as ATC was trying to depart as many aircraft as possible. The airbus was on a st johns departure and we are on a silow. Concern #1: as an efficiency measure; company flight standards imposed a procedure whereby we use a 30 degree bank turn for departure turns. Other airlines do not follow this procedure. The aim only calls for a standard rate turn. The airbus was using what I estimate to be a 15 degree bank turn. This resulted in our being well inside of his turn radius as we both turned to the right. My first officer compensated by increasing his climb and reducing his speed. This kept us safely inside of his turn radius. The silow had us rolling out north while the airbus continued his turn to the east. We easily maintained visual contact with the airbus from takeoff throughout this entire event. Despite these corrections; our separation was dramatically reduced; causing some concern from ATC. I strongly feel that additional supporting verbiage should be added to the fom to temper our directive to use the 30 degree bank. If everyone played by our rules; there would be no problem; but that is just not always the case. Concern #2: despite the fact that we were above and behind the airbus; the TCAS generated a short RA directing a dramatic descent. Clearly; this is exactly what we didn't want to do. Better separation was ensured by continuing our climb. There are 2 concerns here: 1) the TCAS did not generate the RA until we were behind and diverging away from the airbus in other words; much later than it needed to be. 2) it directed an abrupt descent that would have actually decreased our separation. This is perhaps evidence of a software problem. Expand supporting verbiage on fom 3.4.5. Investigate TCAS RA events during climbs and turns to ensure that they are generating proper RA's.

Original NASA ASRS Text

Title: B737-700 FLT CREW EXPERIENCES TCAS RA ON A PHX SID. FEELS RECENT ACR POLICY DIRECTING 30 DEGREE BANKED TURNS DURING DEPARTURE MANEUVERING MAY CONTRIBUTE TO REPEATED INCIDENTS IN THE FUTURE.

Narrative: I HAVE 2 SAFETY CONCERNS ABOUT OUR CURRENT FOM PROCS AND TCAS RA PROGRAMMING. THE EVENT WAS AN RA GENERATED IN OUR TURN TO THE N ON THE DEP FROM PHX. PRECEDING US WAS ANOTHER CARRIER. TKOF SPACING WAS MINIMAL AS ATC WAS TRYING TO DEPART AS MANY ACFT AS POSSIBLE. THE AIRBUS WAS ON A ST JOHNS DEP AND WE ARE ON A SILOW. CONCERN #1: AS AN EFFICIENCY MEASURE; COMPANY FLT STANDARDS IMPOSED A PROC WHEREBY WE USE A 30 DEG BANK TURN FOR DEP TURNS. OTHER AIRLINES DO NOT FOLLOW THIS PROC. THE AIM ONLY CALLS FOR A STANDARD RATE TURN. THE AIRBUS WAS USING WHAT I ESTIMATE TO BE A 15 DEG BANK TURN. THIS RESULTED IN OUR BEING WELL INSIDE OF HIS TURN RADIUS AS WE BOTH TURNED TO THE R. MY FO COMPENSATED BY INCREASING HIS CLB AND REDUCING HIS SPD. THIS KEPT US SAFELY INSIDE OF HIS TURN RADIUS. THE SILOW HAD US ROLLING OUT N WHILE THE AIRBUS CONTINUED HIS TURN TO THE E. WE EASILY MAINTAINED VISUAL CONTACT WITH THE AIRBUS FROM TKOF THROUGHOUT THIS ENTIRE EVENT. DESPITE THESE CORRECTIONS; OUR SEPARATION WAS DRAMATICALLY REDUCED; CAUSING SOME CONCERN FROM ATC. I STRONGLY FEEL THAT ADDITIONAL SUPPORTING VERBIAGE SHOULD BE ADDED TO THE FOM TO TEMPER OUR DIRECTIVE TO USE THE 30 DEG BANK. IF EVERYONE PLAYED BY OUR RULES; THERE WOULD BE NO PROB; BUT THAT IS JUST NOT ALWAYS THE CASE. CONCERN #2: DESPITE THE FACT THAT WE WERE ABOVE AND BEHIND THE AIRBUS; THE TCAS GENERATED A SHORT RA DIRECTING A DRAMATIC DSCNT. CLRLY; THIS IS EXACTLY WHAT WE DIDN'T WANT TO DO. BETTER SEPARATION WAS ENSURED BY CONTINUING OUR CLB. THERE ARE 2 CONCERNS HERE: 1) THE TCAS DID NOT GENERATE THE RA UNTIL WE WERE BEHIND AND DIVERGING AWAY FROM THE AIRBUS IN OTHER WORDS; MUCH LATER THAN IT NEEDED TO BE. 2) IT DIRECTED AN ABRUPT DSCNT THAT WOULD HAVE ACTUALLY DECREASED OUR SEPARATION. THIS IS PERHAPS EVIDENCE OF A SOFTWARE PROB. EXPAND SUPPORTING VERBIAGE ON FOM 3.4.5. INVESTIGATE TCAS RA EVENTS DURING CLBS AND TURNS TO ENSURE THAT THEY ARE GENERATING PROPER RA'S.

Data retrieved from NASA's ASRS site as of January 2009 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.

B737-700 flight crew experiences TCAS RA on a phx SID. Feels recent air carrier policy directing 30 degree banked turns during departure maneuvering may contribute to repeated incidents in the future.