AVSIG: NBAA: Over 17% of flights foregoing control check wwswsigarch.jpg (7236 bytes)

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Mac Tichenor (DAL)
Top Gun


Reged: 06/04/04
Posts: 1857
NBAA: Over 17% of flights foregoing control check
      #430929 - 09/22/16 01:18 AM

The 2014 multi-fatality G-IV accident at KBED was particularly shocking for the experienced crew's failure to run a pre-flight check of the flight controls. This routine check would have revealed that the external gust lock was still in place.

In the aftermath, the NTSB tasked NBAA with determining the prevalence of non-compliance with "manufacturer-required routine flight-control checks before takeoff." The NBAA recenlty released its findings.

NBAA analyzed 143,756 business aviation flights* from the years 2013, 2014 and 2015. They found that for 17.6% of flights, there was no C in CIGAR. The data show there was a brief period of increased compliance shortly after the accident, but it it soon returned to previous levels.

Stunning.
______________________________________________________

*the data were available through a voluntary program wherein operators submit flight recorder data to a clearinghouse where it is de-identified and pooled. It's reasonable to assume that the operators who go to this trouble are more safety conscious than average.


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Scott Dunham (RDU)
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Reged: 04/29/04
Posts: 6470
Loc: Chapel Hill, NC
Re: NBAA: Over 17% of flights foregoing control check [Re: Mac Tichenor (DAL)]
      #430930 - 09/22/16 01:33 AM

>> Stunning...

No kidding. Some of this stuff is so freaking basic that you'd think it would NEVER be left out, yet there are the stats...


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Mase Taylor
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Reged: 04/29/04
Posts: 9446
Loc: SOCAL
Re: NBAA: Over 17% of flights foregoing control check [Re: Mac Tichenor (DAL)]
      #430932 - 09/22/16 02:07 AM

That's just amazing. I can't imagine being that complacent.

--------------------
Fly The Airplane As Far Into The Crash As Possible. - Bob Hoover 1922-2016 R.I.P.


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Jeff Hartmann CIC
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Reged: 05/18/04
Posts: 7323
Loc: Chico,CA
Re: NBAA: Over 17% of flights foregoing control check [Re: Mac Tichenor (DAL)]
      #430946 - 09/22/16 01:15 PM

Not being a GIV guy, I wonder, are the controls locked with hydraulics, but allow the yoke to move?

Like others, I can't imagine pushing up power without rolling the yoke back and forth.

I think someone mentioned that they could not be released after hydraulic pressure was up...(?)

(maybe if I read the report...)

--------------------
Jeff

nothing clever to say right now...


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Scott Dunham (RDU)
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Reged: 04/29/04
Posts: 6470
Loc: Chapel Hill, NC
Re: NBAA: Over 17% of flights foregoing control check [Re: Jeff Hartmann CIC]
      #431010 - 09/25/16 02:02 AM

http://dms.ntsb.gov/public/57000-57499/57175/570982.pdf

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Jeff Hartmann CIC
Top Gun


Reged: 05/18/04
Posts: 7323
Loc: Chico,CA
Re: NBAA: Over 17% of flights foregoing control check [Re: Scott Dunham (RDU)]
      #431012 - 09/25/16 11:32 AM

So, if they started, and then pushed the handle forward, there could be binding on the gust locks, or even pressure applied to the controls could bind them and prevent release.
Quote:

To prevent any hydraulic forces acting upon an
engaged gust lock, the gust lock should be released prior to engine starting
and not engaged until all hydraulic pressures read zero




Reminds me of a Helio Courier that crashed, where the owner used a nail or screw to lock the controls, and on takeoff could not pull it out with air loads on the controls.

Thanks

--------------------
Jeff

nothing clever to say right now...


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Mac Tichenor (DAL)
Top Gun


Reged: 06/04/04
Posts: 1857
Re: NBAA: Over 17% of flights foregoing control check [Re: Scott Dunham (RDU)]
      #431019 - 09/25/16 10:54 PM Attachment (106 downloads)


Ah, I mis-remembered that it was a mechanical gust lock.

So someone set takeoff flaps without noticing that gust lock handle was in the way?

>>Movement of both power levers is restricted to no more than 6% above idle.<< Good idea. Too bad it was only wishful thinking.

Edited by Mac Tichenor (DAL) (09/25/16 10:59 PM)


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Jeff Hartmann CIC
Top Gun


Reged: 05/18/04
Posts: 7323
Loc: Chico,CA
Re: NBAA: Over 17% of flights foregoing control check [Re: Mac Tichenor (DAL)]
      #431028 - 09/26/16 09:47 AM

Mac,

Read through what Scott posted, it sounds like they may have (could have) pushed the control lock off, after hydraulic pressure on the system would (could) keep the pins engaged. Handle forward, throttles forward.
I still wonder if the yoke would move, with pinned controls, applying pressure without motion...(?)

I have a hard time believing that no one had tried to move the controls taxing out...

--------------------
Jeff

nothing clever to say right now...


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Mac Tichenor (DAL)
Top Gun


Reged: 06/04/04
Posts: 1857
Re: NBAA: Over 17% of flights foregoing control check [Re: Jeff Hartmann CIC]
      #431042 - 09/26/16 02:25 PM

Well, you prompted me to dig into this... A video of NTSB hearing is available online. At about 44:05, the vice-chair asks about this specifically. The NTSB investigators determined that the gust lock handle was up (engaged) at the beginning of the takeoff roll (they could tell that power lever travel was limited, and that limitation is a result of a mechanical link to the gust lock lever handle).

The POH excerpt that Scott posted refers to a 6% power lever travel limitation. The investigators referred to degrees rather than percent, including referring to the design limit as 6 degrees. Wonder if the POH should've said 6 degrees instead of 6%?

In any event, the purported 6% power lever travel limitation turned out to be 17-degrees on the accident aircraft.* I don't know anything about the G-IV but It's hard imagine that having the levers stop at 17 degrees wouldn't make you re-think your takeoff plan. Instead, they engaged the auto throttles, which somewhat masked the problem by transiently providing more power.

*later testing on a sample of G-IVs showed a range up to 23-24 degrees.

V1 was called at 118 kts, Vr at 125 (all these speeds are ground speeds). At 129 the PIC said "Steer lock is on" This is probably when the gust lock lever was stowed but presumably with too much aerodynamic force on the elevator to allow disengagement of the "hook" that locked it in the full nose down position.

Seven seconds later, at 148 kts, one of the pilots shut off hydraulic power to the control surfaces but still with no effect.

Brakes were applied 11 seconds after the rotate call. Ground speed was 168 kts. The power levers were pulled back four seconds after that. Reversers were deployed shortly after the aircraft entered the paved overrun area. It departed the overrun going 105 kts.


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Jeff Hartmann CIC
Top Gun


Reged: 05/18/04
Posts: 7323
Loc: Chico,CA
Re: NBAA: Over 17% of flights foregoing control check [Re: Mac Tichenor (DAL)]
      #431044 - 09/26/16 02:35 PM

Sounds like they tried to avoid embarrassment by not aborting, and fiddle farting with it during acceleration instead.

Wow, that makes it worse for me...

It is easy to be complacent.

--------------------
Jeff

nothing clever to say right now...

Edited by Jeff Hartmann (EXX/SVH) (09/26/16 02:36 PM)


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