Pilot drifted above cleared altitude conflicting with opposite direction traffic. The pilot reporter...

Attributes
ACN	1324254
Time
Date	201601
Local Time Of Day	1801-2400
Place
Locale Reference	ZZZ.Airport
State Reference	US
Environment
Flight Conditions	VMC
Light	Night
Aircraft 1
Make Model Name	Light Transport Low Wing 2 Turboprop Eng
Operating Under FAR Part	Part 135
Flight Phase	Cruise
Route In Use	Direct
Flight Plan	IFR
Aircraft 2
Make Model Name	Small Transport
Flight Phase	Cruise
Person 1
Function	Single Pilot
Qualification	Flight Crew Air Transport Pilot (ATP) Flight Crew Flight Instructor Flight Crew Multiengine
Experience	Flight Crew Last 90 Days 150 Flight Crew Total 11030 Flight Crew Type 1825
Events
Anomaly	Conflict Airborne Conflict Deviation - Altitude Overshoot Deviation - Altitude Excursion From Assigned Altitude Deviation - Procedural Clearance

Narrative:

After driving 6 hours and being fatigued from flying 32 legs the previous week; I deviated from my assigned altitude. The controller pointed out the oncoming traffic; which I even altered course 15 degrees to avoid the oncoming aircraft. I suddenly discovered that I exceeded my assigned altitude of 12000 feet by at least 500 feet. I rapidly made a descent back down to 12000 feet. Visual contact with the oncoming aircraft was never lost until passing and my main goal was to maintain visual separation with that traffic.I would be remiss if I didn't say that fatigue and emotional factors contributed greatly to this pilot deviation. My company is short on pilots and long on work. I was covering this run for the time being until we hire a pilot to fly it permanently. Just another example that even if you are getting legal crew rest doesn't mean it's safe.

Original NASA ASRS Text

Title: Pilot drifted above cleared altitude conflicting with opposite direction traffic. The pilot reporter corrected the error after Controller advised him of the situation. Pilot commented fatigue was a contributing factor.

Narrative: After driving 6 hours and being fatigued from flying 32 legs the previous week; I deviated from my assigned altitude. The controller pointed out the oncoming traffic; which I even altered course 15 degrees to avoid the oncoming aircraft. I suddenly discovered that I exceeded my assigned altitude of 12000 feet by at least 500 feet. I rapidly made a descent back down to 12000 feet. Visual contact with the oncoming aircraft was never lost until passing and my main goal was to maintain visual separation with that traffic.I would be remiss if I didn't say that fatigue and emotional factors contributed greatly to this pilot deviation. My company is short on pilots and long on work. I was covering this run for the time being until we hire a pilot to fly it permanently. Just another example that even if you are getting legal crew rest doesn't mean it's safe.

Data retrieved from NASA's ASRS site 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.

Pilot drifted above cleared altitude conflicting with opposite direction traffic. The pilot reporter corrected the error after controller advised him of the situation. Pilot commented fatigue was a contributing factor.