Sinak is located at the eastern end of the Freeway, in a side valley to the south a few miles from Mulia airstrip. It’s a fairly popular destination from all four of the major Papuan airports (Nabire, Timika, Sentani and Wamena) and being long enough for a Cessna Caravan, makes it a popular destination for a variety of cargo loads.

Final approach into Sinak airstrip, Papua

Runway statistics

Orientation: 08/26 (Landing 26, take-off 08)
Length: 650m
Elevation: 6700ft
Slope: 10% up-slope
Surface: course gravel/stones, very rough in places

Unloading fuel drums in Sinak, Papua

Pilot notes

The valley Sinak is located in is fairly wide and orientated north-south. Weather wise, first thing in the morning it can be fogged in, especially if there’s been any overnight rain, so I find it better to arrive any time from mid-morning to early afternoon. Winds tend to pick-up from mid-morning onwards and it’s not unusual to have 20kts+ gusting up the valley creating some interesting crosswinds from the north.
The approach into Sinak has a rather large hill just off to the right side (as can be seen in the photo below) which makes for a slightly more interesting approach than it would otherwise be. That hill also creates quite a lot of turbulence on the approach as it swirls around and over it. Provided you can safely get through the turbulence on the approach, the winds settle down from around 100ft from the airstrip itself allowing for a smooth touchdown.
Departure from Sinak airstrip, Papua

That quartering (tailwind) crosswind however tends not to ease up and one thing you don’t want to do with any aircraft, especially a large tailwheel aircraft like the Porter, is touchdown crooked. However, the long length and constant up-slope of Sinak allows you to fly up the airstrip for a touchdown nearer the top and perfectly straight. Landing deeper into the airstrip is actually of benefit anyway, as the lower parts of Sinak tend to be home to the larger rocks which can easily puncture the coke-can thin skin of the Porter’s horizontal stabiliser and elevator.

The departure is a lot easier and that tailwind on landing becomes a headwind that helps you get airborne a little quicker. I always like to pick the tailwheel up off the ground as early as possible by pushing forward on the control stick as soon as I start adding power. The ground roll doesn’t tend to be much but anything you can do to minimise the chances of punching a hole in the aircraft are worth doing.

I also tend to hold off retracting the flaps until well clear of that hill and, if necessary, use ground effect along the airstrip to accelerate the aircraft to a higher speed before starting the climb. The last thing you want to be doing is climbing away at too low a speed, encounter wind-shear and stall close to the ground. Once clear of the turbulence and terrain, I get the flaps up and climb away into the valley for the return back to Nabire or Timika.

Unloading cargo, Sinak, Papua
Matt Dearden

Matt Dearden

English born professional pilot, writer, blogger and columnist. Currently flying the Pilatus PC-6 Turbo Porter in Papua, Indonesia.

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