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PC12 stall testing



Someone told me the type could not be certified until they added a stick shaker. Is that correct?

Administrator
Shoreham EGKA, United Kingdom

Shaker and even a Stick Pusher. You have to test it before each flight.

LFPT Pontoise, LFPB

I am so pleased my trusty 172 stalls in a more benign manner!

UK, United Kingdom

And yet, no inflight breakups… What incredible machines.

EGTF, LFTF

Look quite benign incipient spins, they may be testing skidding and slipping stalls, so context might be useful. Some looked slightly accelerated (high alpha with a pull into the stall).

Some operators use the yoke mounted stick shaker/pusher disconnect button in the flare, so the type is more benign in the stall regime than this video clip suggests.

Oxford (EGTK), United Kingdom

Yikes, about 1000ft loss shown on the altimeter with that nose down, the perks of flying high aerodynamic performance machines

Does he intentionally makes wing drop by pulling ailerons to their stop? what happens if he just pulls with no roll inputs?
It does not look like 1G symmetric stall inputs to me

Last Edited by Ibra at 02 Oct 10:34
Paris/Essex, France/UK, United Kingdom

The PC12 has very benign stall characteristics at low power settings. However at high power settings (75% MCP) and high deck angle (30’ nose up) the wings will stall at 45 kcas, while the elevator retains authority (thereby not meeting Part 23 req of “loss of elevator authority and pitchdown”). Wing roll will be significant at that power setting and attitude as ailerons lose authority, and the problem is exacerbated by rearward CG (oh and flaps, forgot that one).

As a result, instead of changing wing design the stick shaker / pusher was added.

Last Edited by T28 at 02 Oct 10:55
T28
Switzerland

So do I understand correctly – with power off, it has the ‘expected’ stall behaviour where the nose drops, aiding recovery, but at high power settings the nose remains high?

If that happens, can the pilot recover from that by applying full forward elevator, or does the stick pusher have to save the day before it gets to that point?

Biggin Hill

At high power settings the nose remains “where you put it” as the elevator has enormous authority and does not run out of travel.

You can recover by modulating elevator input (having said that it will probably quickly point downwards due to significant wing drop anyway, a bit like the Mustang), but it does not meet FAR 23, hence the need for the pusher. It was also thought that some pilots might be startled by the continued elevator authority and continue pulling up into the stall…

Last Edited by T28 at 02 Oct 11:05
T28
Switzerland

Interesting that he recovers with the ailerons and doesn’t seem to reduce any power in the dive.

ESME, ESMS
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