Flight Crew Multiengine; Flight Crew Instrument; Flight Crew Commercial; Flight Crew Flight Instructor
Flight Crew Last 90 Days 45; Flight Crew Type 45
Situational Awareness; Human-Machine Interface; Communication Breakdown
Aircraft Equipment Problem Critical; Deviation / Discrepancy - Procedural FAR; Deviation / Discrepancy - Procedural Published Material / Policy; Deviation / Discrepancy - Procedural Clearance; Inflight Event / Encounter Fuel Issue
Air Traffic Control Provided Assistance; Flight Crew Diverted; Flight Crew Requested ATC Assistance / Clarification; Flight Crew Overcame Equipment Problem; Flight Crew Landed As Precaution; General Flight Cancelled / Delayed
Aircraft; Procedure; Human Factors
The flight was from ZZZ to ZZZ1 back to ZZZ. we departed around XApm; landed ZZZ1 around XC:15pm. on the return flight back to ZZZ near by ZZZ2; the engine was rough and partially lost power and we [requested priority handling] right away with ZZZ3 Approach. We did our best to land aircraft safely at ZZZ2 and no one was injured. Before the flight; we did the flight plan; based on the POH (Pilot Owner's Handbook); we calculated the fuel burn. Total route is 298 NM; which will cost 3.5 hours. So we should have had remaining 1 hour fuel. I believe low fuel caused the problem. In the future I will pay more attention to the fuel; do not trust fuel indicator; give myself a bigger fuel margin.
On a 298 NM flight from ZZZ to ZZZ1 and back to ZZZ in a Cessna 152; the PIC calculated fuel burn over the flight based on the POH and fell within the expected reserve requirement.  The plane took off at XA:00 with verified completely full fuel tanks.  When we landed at ZZZ1 at XC:15 and the fuel gauge appeared to show a fuel level in line with calculations to make the return flight.  On the return trip; approximately 20 NM from ZZZ at around XD:45; the engine was rough and lost partial power.  I immediately radioed in and [requested priority handling] with ZZZ3 Approach and the tower requested that I remain on frequency and cleared our aircraft for immediate landing at ZZZ2.  The PIC landed the plane safely without power; there was no damage; and no one was injured.   Between the timing of the failure and calculated fuel burn; the numbers did not align. We followed every altitude assigned by ATC along the flight; leaned the fuel mixture and kept appropriate power as calculated but margin was insufficient.  In the future I will take an even more conservative approach to my own fuel calculations after this impactful experience.
Flight crew reported partial engine power loss during cruise. The flight crew elected to divert and make a precautionary landing.