Beechcraft King Air 360 Er vs Bell 525 Relentless vs Piper M600 Sls

The Beechcraft King Air 360ER and Piper M600 SLS are both fixed‑wing turboprops, while the Bell 525 Relentless is a twin‑engine helicopter. In category terms, the King Air 360ER sits in the twin‑engine pressurized utility/business turboprop class, optimized for multi‑passenger regional missions and flexible airports. The Piper M600 SLS is a single‑engine pressurized personal/business turboprop, typically positioned as a high‑end owner‑flown or small‑team aircraft. The Bell 525 is a super‑medium helicopter aimed at executive transport and offshore/utility roles where vertical lift matters more than runway performance. On range, the King Air 360ER generally offers the longest fixed‑wing endurance in this group (roughly on the order of 1,500 nm depending on configuration and reserves), the M600 SLS follows (about 1,400 nm class), and the Bell 525 typically has a shorter still‑air range than the fixed‑wing turboprops (commonly around the ~500–700 nm class, mission‑dependent). For passenger capacity, the King Air 360ER usually carries the most (often 6–9 seats), the Bell 525 commonly seats around 10–16 depending on layout, and the M600 SLS is typically configured for about 4–6 passengers plus a pilot.