Airframe and cabin

Load paths

Rotor lift is carried from the mast into the structure by four rigid suspension bars; a flexible mount under the main gearbox takes the other loads and filters vibration. The gearbox sits on the central section, the airframe's strongest part, with the engine behind it.

The skid gear is attached to the same central section and acts as a spring on landing. A hard landing loads both — and is a maintenance event, not a judgement call.

Sources 1, 4

Tail boom, fin and stabiliser

The vertical fin is shaped to produce sideways lift in forward flight, which takes load off the tail rotor. That's why pedal positions change between hover and cruise.

The horizontal stabiliser keeps the fuselage at a sensible attitude as speed increases. Without it the nose would drop as the disc tilts forward.

A tail skid protects the tail rotor in a nose-high landing. Damage to it is a sign the tail may have touched.

Sources 4, 5

Fin, strakes and inspections

Because the fin carries part of the anti-torque job in cruise, less right pedal is needed there than in the hover. That makes the fin structure matter: after a spar crack was found on an AS355 twin, EASA has required repeated fin inspections on the AS355 and on B3s without a production fin modification since 2017, and in 2023 added a temporary Vne placard for the twin.

Some aircraft carry BLR's FastFin: a strake and a reshaped cowling on the tail boom that change how rotor downwash flows around it, intended to improve tail-rotor margin when hovering in a crosswind. If it is fitted, there is an RFM supplement.

Sources 4, 6, 7

Cabin in numbers

Cabin and holds

The pilot's seat is on the right. Cabin layouts vary — passenger, utility, EMS and tour interiors are all common — and each changes the empty mass and centre of gravity.

Baggage goes in the two side holds and the rear hold, each with its own load limit placarded at the door. A heavy item in the wrong hold is a centre-of-gravity problem, not just a weight one.

Sources 2, 3, 9

Interiors for the job

The cabin is reconfigured for the job. Tour aircraft carry passenger seating, EMS aircraft a stretcher and medical fit, utility aircraft a bare floor with tie-downs, and vertical-reference aircraft often a mirror and a bulged window in the pilot's door.

Every change moves the empty mass and CG, and the interior fitted is part of the weight and balance report. If the cabin has changed since the report was done, the report no longer describes the aircraft.

Sources 8, 9

Doors

There are doors on both sides: a front door for each front seat and rear doors for the cabin. The configuration varies with year and fit; the current H125 baseline has a sliding rear door on the left and a hinged rear door on the right.

Doors are part of the limitations as well as the cabin: which may be removed or opened in flight, and at what speeds, is in the RFM. For rescue services, Airbus publishes a free Ground Rescue Booklet for the H125 covering emergency access.

Before a passenger flight, show each person how their door opens, and check it is latched.

Sources 2, 10, 11

Cowlings and access panels

The engine, main gearbox and the hydraulic components on the upper deck sit under cowlings that hinge open or come off. On the walkaround they are how you see what matters — fluid levels, leaks, servo attachments, the engine bay.

The trap is closing them. A cowling or panel that is not fully latched can open in flight, and anything that leaves the upper deck can reach the main or tail rotor. Check every latch yourself after maintenance or a fluid check, including the ones someone else closed.

Sources 4, 12

Ground handling

Off the pad, the Astar is usually moved on ground-handling wheels fitted to the skids, with someone controlling the tail. Push and pull only where maintenance has shown you; the tail rotor, its control rods and the horizontal stabiliser are not handles.

Parked, the main-rotor blades are tied down so wind cannot flap them or turn the rotor. Ties, covers and handling wheels all have to be off or secured before start — classic last-walk items, because they are fitted after the walkaround is done.

Source 12