A pilot departed on btm runway 33 and once airborne took evasive action to avoid an aircraft departi...

Narrative:

After broadcasting my intentions to taxi to runway 33; I noticed aircraft Y that looked like he'd be taxiing soon. While taxiing I saw the windsock and decided to use runway 29 and broadcast my intentions. I completed the before takeoff checklist and as I was about to taxi; when realized I'd not heard aircraft Y on the radio. I looked toward the terminal but only saw the very top of it; if aircraft Y was still there I could not see it. I then looked toward runway 33 and did not see aircraft Y. I then announced taxiing into position and departing 29 straight out. A few hundred feet down the runway I glanced at the terminal; no airplane where it had been. I then looked toward to 33 and saw aircraft Y on the takeoff roll. I was airborne by then; and instantly did a hard right turn to the east. I never did get to runway 33 in the turn and kept climbing. Only after eastbound did I notice the active frequency was on the wrong frequency and toggled the correct frequency into the active spot. I do not know when the CTAF frequency was toggled away. The G1000 has several small buttons; squelch volume control; frequency transfer; and a button to switch to the other radio to change frequencies. More separation would be helpful.

Original NASA ASRS Text

Title: A pilot departed on BTM Runway 33 and once airborne took evasive action to avoid an aircraft departing Runway 29 which he did not hear because his G1000 had switched from the CTAF frequency.

Narrative: After broadcasting my intentions to taxi to Runway 33; I noticed Aircraft Y that looked like he'd be taxiing soon. While taxiing I saw the windsock and decided to use Runway 29 and broadcast my intentions. I completed the before takeoff checklist and as I was about to taxi; when realized I'd not heard Aircraft Y on the radio. I looked toward the terminal but only saw the very top of it; if Aircraft Y was still there I could not see it. I then looked toward Runway 33 and did not see Aircraft Y. I then announced taxiing into position and departing 29 straight out. A few hundred feet down the runway I glanced at the terminal; no airplane where it had been. I then looked toward to 33 and saw Aircraft Y on the takeoff roll. I was airborne by then; and instantly did a hard right turn to the east. I never did get to Runway 33 in the turn and kept climbing. Only after eastbound did I notice the active frequency was on the wrong frequency and toggled the correct frequency into the active spot. I do not know when the CTAF frequency was toggled away. The G1000 has several small buttons; squelch volume control; frequency transfer; and a button to switch to the other radio to change frequencies. More separation would be helpful.

Data retrieved from NASA's ASRS site as of April 2012 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.

Attributes
ACN	971007
Time
Date	201109
Local Time Of Day	1201-1800
Place
Locale Reference	BTM.Airport
State Reference	MT
Environment
Flight Conditions	VMC
Light	Daylight
Aircraft 1
Make Model Name	Small Aircraft High Wing 1 Eng Retractable Gear
Operating Under FAR Part	Part 91
Flight Phase	Takeoff
Flight Plan	None
Aircraft 2
Make Model Name	Any Unknown or Unlisted Aircraft Manufacturer
Flight Phase	Takeoff
Component
Aircraft Component	Air/Ground Communication
Person 1
Function	Pilot Flying Single Pilot
Qualification	Flight Crew Air Transport Pilot (ATP) Flight Crew Flight Instructor Flight Crew Multiengine
Experience	Flight Crew Last 90 Days 81 Flight Crew Total 16000 Flight Crew Type 235
Events
Anomaly	Conflict NMAC

A pilot departed on btm runway 33 and once airborne took evasive action to avoid an aircraft departing runway 29 which he did not hear because his G1000 had switched from the CTAF frequency.