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Tuesday, November 25, 2014

DON'T TOUCH THAT KNOB!

Since the installation of Appareo video and data recorders in EMS helicopters, there have been three separate incidents - two of them fatal helicopter crashes - in which a pilot continued flight into bad weather, became disoriented, and allowed the aircraft to enter unusual attitudes.

He then reached forward and caged the attitude indicator.

DON'T DO THAT!

Let's consider what is happening  The pilot elects to fly under visual flight rules into reduced ceiling or visibility. He either thinks that he is up to the task of instrument flight, or he hopes that things won't get worse and will get better shortly. Things don't get better and the pilot loses ground reference entirely. He is in the goo and cannot tell which way is up or down by looking out the window

Although he may have some experience flying on instruments, he is not proficient; and he loses control of the aircraft, allowing it to get into an unusual attitude. This often occurs during a turn back to where things were better.

By now his vestibular and proprioceptive systems are lying to him, At some point he realizes he has gone too far, and fear kicks in. It's tragic that he wasn't more afraid sooner.

He looks at his attitude indicator, and doesn't believe it. It is tilted over on it's side, and pitched up or down, and it just can't be right. He doesn't "feel" like he is turning and diving.

So he takes his hand and re-cages the gauge. 



Several seconds later (at 2318:40), with the helicopter at high pitch and roll angles, the
pilot pulled a knob on the instrument panel to cage the attitude indicator (which sets it to display
a level flight attitude). Caging an attitude indicator is meant to be performed only when an
aircraft is in a level flight attitude, such as on the ground or in straight-and-level, unaccelerated
flight. As an experienced pilot and mechanic, he would have understood the conditions under
which the attitude indicator could be safely caged. Therefore, the NTSB concludes that the
pilot’s action to cage the attitude indicator outside those conditions under which it could be
safely caged indicates that he distrusted the information he was seeing. (Possible reasons for this
distrust are discussed in section 2.6.) By caging the attitude indicator while the helicopter was at
high pitch and roll angles, the pilot caused the instrument to provide erroneous attitude
indications that would be difficult to ignore in a high-stress situation

Click here for full report...

The attitude indicator, if caged while upside down, will indicate right side up. If you have just caged the attitude indicator in the picture above, with your aircraft upside down, it is still upside down!

God forbid, if you are a crew member and I have taken you into the clouds, and you see me reaching for that knob - tell me THAT WON'T WORK.

The attitude indicators on early aircraft failed often. The were considered a "secondary" instrument, less reliable than the altimeter, vertical speed indicator, heading indicator, and turn indicator. Pilots are required to demonstrate the ability to fly "partial panel" with a cover over the attitude indicator during instrument proficiency checks - but VFR EMS  helicopter pilots - even though an instrument "rating" is required, do not have to take an instrument check ride. We must only demonstrate the ability to recover from an unusual attitude and shoot a single approach.

This is not enough to prepare a visual pilot for instrument conditions.

So we better stop or divert before we get there - in the clouds, or snow, or heavy rain,. Stop because we aren't prepared, we aren't proficient, we aren't ready.

And three of us have proved it by putting their hand on a knob.

This pilot made the mistake - and lived to tell the tale. Click here.

Disclosure: During my last check ride with my company, I was forced to demonstrate partial panel flying, with a cover over the AI. This is the first time in twenty five years or so that I had to do this. It is very good training and something we should all do regularly. You do not need an attitude indicator to fly on instruments. Practice, practice, practice.

VFR EMS pilots should be required to take an instrument proficiency check at least once a year. A real check ride, not one approach.

Crews - do not let your VFR  pilot take you into instrument conditions. Please. You can prevent a fatal crash. If you know of team members who are not as familiar with what is happening here - such as pediatric or neo-nate team members, or perfusionists - people who don't fly as often and don't hear about events like this,  please call them and discuss this. You may save their lives.

Speak up!

1 comment:

  1. Good article. At Abu Dhabi Aviation we had an instrument check ride in the flight simulator every six months which, from what I saw in the sim and as an examiner, should be the very minimum. Once a year is not enough as flying on instruments, as you know, is the most perishable skill we pilots have.

    ReplyDelete

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