C210T has near midair collision near act.

Attributes
ACN	730733
Time
Date	200703
Local Time Of Day	1201 To 1800
Place
Locale Reference	airport : act.airport
State Reference	TX
Altitude	msl single value : 5600
Environment
Flight Conditions	VMC
Light	Daylight
Aircraft 1
Operator	general aviation : personal
Make Model Name	Cessna 210 Centurion / Turbo Centurion 210C 210D
Operating Under FAR Part	Part 91
Flight Phase	cruise : level
Flight Plan	VFR
Aircraft 2
Controlling Facilities	tracon : act.tracon
Make Model Name	Any Unknown or Unlisted Aircraft Manufacturer
Person 1
Affiliation	other
Function	flight crew : single pilot
Qualification	pilot : cfi pilot : commercial pilot : instrument pilot : multi engine pilot : atp
Experience	flight time last 90 days : 20 flight time total : 3500 flight time type : 600
ASRS Report	730733
Events
Anomaly	aircraft equipment problem : less severe conflict : nmac
Independent Detector	other flight crewa
Resolutory Action	flight crew : took evasive action
Miss Distance	horizontal : 0 vertical : 50
Supplementary
Problem Areas	Flight Crew Human Performance ATC Human Performance Airspace Structure
Primary Problem	Ambiguous

Narrative:

I was flying level; slightly east of a southerly heading (about 170 degrees); about 0.7 NM west of the act class D airspace (and above the upper limit of the class D airspace). I was monitoring waco approach; though not in contact with them. I heard waco approach's alarm go off in the background while waco approach was transmitting to someone. They gave an aircraft a TA which included the warning that they had traffic directly ahead at their 12 O'clock position. Apparently he did not alter his direction of flight because the next thing that happened several seconds later is that I saw an aircraft coming towards me from the southeast just as he pulled up and passed very close over the top of me. I then heard the controller query him. He replied that he had just seen the other aircraft pass just below him. My zaon traffic alerter had given me a warning; but it showed the other aircraft coming from a direction at about 90 degrees to the left of my flight path; and so I was visually searching at the horizon on my left. Since I did not see the other aircraft; even with a wide scan; I wonder if it was climbing up towards me such that I did not see it in the ground clutter to the southeast. If so; he should have easily detected me since my airplane would have been above the horizon in his view. The other aircraft was heading northwest at what I would guess to be a heading of about 300 degrees. If the other aircraft was in cruise; then the other aircraft was not an appropriate altitude for his direction of flight. He should have been at even +500 ft if he was flying VFR (4500 ft or 6500 ft); or on a 1000 ft altitude if he was IFR (5000 ft or 6000 ft). However; he might have been climbing or descending. What I learned from this is the following: 1) I might have been better off if I had been on flight following myself instead of just monitoring the waco approach frequency. 2) you can't trust the even/odd cruise rules. Some pilots don't follow them; and besides that; the pilot may be climbing or descending. 3) the traffic alerter is not very accurate on direction. Don't assume that it is correct to the nearest 45 degrees. Assume it is only generally correct to the nearest 180 degrees.

Original NASA ASRS Text

Title: C210T HAS NMAC NEAR ACT.

Narrative: I WAS FLYING LEVEL; SLIGHTLY E OF A SOUTHERLY HDG (ABOUT 170 DEGS); ABOUT 0.7 NM W OF THE ACT CLASS D AIRSPACE (AND ABOVE THE UPPER LIMIT OF THE CLASS D AIRSPACE). I WAS MONITORING WACO APCH; THOUGH NOT IN CONTACT WITH THEM. I HEARD WACO APCH'S ALARM GO OFF IN THE BACKGROUND WHILE WACO APCH WAS XMITTING TO SOMEONE. THEY GAVE AN ACFT A TA WHICH INCLUDED THE WARNING THAT THEY HAD TFC DIRECTLY AHEAD AT THEIR 12 O'CLOCK POS. APPARENTLY HE DID NOT ALTER HIS DIRECTION OF FLT BECAUSE THE NEXT THING THAT HAPPENED SEVERAL SECONDS LATER IS THAT I SAW AN ACFT COMING TOWARDS ME FROM THE SE JUST AS HE PULLED UP AND PASSED VERY CLOSE OVER THE TOP OF ME. I THEN HEARD THE CTLR QUERY HIM. HE REPLIED THAT HE HAD JUST SEEN THE OTHER ACFT PASS JUST BELOW HIM. MY ZAON TFC ALERTER HAD GIVEN ME A WARNING; BUT IT SHOWED THE OTHER ACFT COMING FROM A DIRECTION AT ABOUT 90 DEGS TO THE L OF MY FLT PATH; AND SO I WAS VISUALLY SEARCHING AT THE HORIZON ON MY L. SINCE I DID NOT SEE THE OTHER ACFT; EVEN WITH A WIDE SCAN; I WONDER IF IT WAS CLBING UP TOWARDS ME SUCH THAT I DID NOT SEE IT IN THE GND CLUTTER TO THE SE. IF SO; HE SHOULD HAVE EASILY DETECTED ME SINCE MY AIRPLANE WOULD HAVE BEEN ABOVE THE HORIZON IN HIS VIEW. THE OTHER ACFT WAS HEADING NW AT WHAT I WOULD GUESS TO BE A HDG OF ABOUT 300 DEGS. IF THE OTHER ACFT WAS IN CRUISE; THEN THE OTHER ACFT WAS NOT AN APPROPRIATE ALT FOR HIS DIRECTION OF FLT. HE SHOULD HAVE BEEN AT EVEN +500 FT IF HE WAS FLYING VFR (4500 FT OR 6500 FT); OR ON A 1000 FT ALT IF HE WAS IFR (5000 FT OR 6000 FT). HOWEVER; HE MIGHT HAVE BEEN CLBING OR DSNDING. WHAT I LEARNED FROM THIS IS THE FOLLOWING: 1) I MIGHT HAVE BEEN BETTER OFF IF I HAD BEEN ON FLT FOLLOWING MYSELF INSTEAD OF JUST MONITORING THE WACO APCH FREQ. 2) YOU CAN'T TRUST THE EVEN/ODD CRUISE RULES. SOME PLTS DON'T FOLLOW THEM; AND BESIDES THAT; THE PLT MAY BE CLBING OR DSNDING. 3) THE TFC ALERTER IS NOT VERY ACCURATE ON DIRECTION. DON'T ASSUME THAT IT IS CORRECT TO THE NEAREST 45 DEGS. ASSUME IT IS ONLY GENERALLY CORRECT TO THE NEAREST 180 DEGS.

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.