Narrative:

During arrival at mvy, tower instructed me to follow a cherokee at my 9 O'clock position. With a ground speed of 230 KTS. I requested left base entry (arriving from the north). Tower denied the request and instructed me to report midfield downwind to runway 6. From the current position it required me to turn left, go around the cherokee. As I commenced the turn to re-enter the downwind, my aircraft and another company aircraft that departed runway 6 and turned northbound on course were in a compromising position that required both pilots to make evasive maneuvers to avoid collision. Supplemental information from acn 631468: during rollout, tower advises of traffic entering from different areas. In general, no altitudes or clock position. Flew runway heading to 700 ft, initiated l-hand turn to 340 degrees. Through 1000 ft I turned off lights and pumps and accelerated to 130 KTS per company profile. Through 1300 ft MSL, I notice company at 12 O'clock position on a collision course. Company traffic made constant altitude left bank. So I made hard left bank with descent to put some distance in altitude. I called tower upon arrival north boston. Controller said 'we told the company traffic to enter midfield left downwind for runway 6. He asked for left base. Tower said to 'follow cherokee on downwind, our radar shows him on downwind.' he was a lot more to the northeast than we thought. No TA's regarding altitude or clock position were given once airborne.

Related reports:

Google
 

Original NASA ASRS Text

Title: A402 ENTERING TFC PATTERN AT MVY AT 1200 FT EXPERIENCED NMAC WITH C402 DEPARTING PATTERN.

Narrative: DURING ARR AT MVY, TWR INSTRUCTED ME TO FOLLOW A CHEROKEE AT MY 9 O'CLOCK POS. WITH A GND SPD OF 230 KTS. I REQUESTED L BASE ENTRY (ARRIVING FROM THE N). TWR DENIED THE REQUEST AND INSTRUCTED ME TO RPT MIDFIELD DOWNWIND TO RWY 6. FROM THE CURRENT POS IT REQUIRED ME TO TURN L, GO AROUND THE CHEROKEE. AS I COMMENCED THE TURN TO RE-ENTER THE DOWNWIND, MY ACFT AND ANOTHER COMPANY ACFT THAT DEPARTED RWY 6 AND TURNED NBOUND ON COURSE WERE IN A COMPROMISING POS THAT REQUIRED BOTH PLTS TO MAKE EVASIVE MANEUVERS TO AVOID COLLISION. SUPPLEMENTAL INFO FROM ACN 631468: DURING ROLLOUT, TWR ADVISES OF TFC ENTERING FROM DIFFERENT AREAS. IN GENERAL, NO ALTS OR CLOCK POS. FLEW RWY HDG TO 700 FT, INITIATED L-HAND TURN TO 340 DEGS. THROUGH 1000 FT I TURNED OFF LIGHTS AND PUMPS AND ACCELERATED TO 130 KTS PER COMPANY PROFILE. THROUGH 1300 FT MSL, I NOTICE COMPANY AT 12 O'CLOCK POS ON A COLLISION COURSE. COMPANY TFC MADE CONSTANT ALT L BANK. SO I MADE HARD L BANK WITH DSCNT TO PUT SOME DISTANCE IN ALT. I CALLED TWR UPON ARR N BOSTON. CTLR SAID 'WE TOLD THE COMPANY TFC TO ENTER MIDFIELD L DOWNWIND FOR RWY 6. HE ASKED FOR L BASE. TWR SAID TO 'FOLLOW CHEROKEE ON DOWNWIND, OUR RADAR SHOWS HIM ON DOWNWIND.' HE WAS A LOT MORE TO THE NE THAN WE THOUGHT. NO TA'S REGARDING ALT OR CLOCK POS WERE GIVEN ONCE AIRBORNE.

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.