G-IV Crash at KBED follow up

[Old Boeing Driver]

Gulfstream has just published a "Maintenance and Operations Letter regarding the gust lock system.

I wonder if they "know" something?

I copied and pasted as I do not know how to attach the PDF.

Regards,

OBD

FLIGHT CREW OPERATIONAL INFORMATION
TO: All Gulfstream Operators
SUBJECT: Flight Controls (ATA 27) – Gust Lock System
Gulfstream issued Maintenance and Operations Letter (MOL) ALL-MOL-14-0015 on June 13, 2014,
which reminded operators of the importance of adhering to Airplane Flight Manual (AFM) procedures
to confirm flight control integrity and freedom of movement. The procedures direct flight crews to
ensure the gust lock is released prior to engine start (not applicable for G650, which does not have a
gust lock system), and that all flight controls are free to move through their full travel prior to taxi and
during subsequent ground movement.
While a throttle interlock is incorporated in the design of the gust lock system, if proper unlock
procedures are not followed, movement of the throttle to a position capable of providing sufficient
engine power for autothrottle engagement and takeoff power may be possible for GIV models.
Throttle movement is not an absolute indicator of the gust lock status for any Gulfstream model. The
freedom of flight control movement is the ultimate indicator the gust lock is fully released for all
Gulfstream models.
As mentioned in the previous MOL, flight crews are reminded to perform the following as set forth in
the applicable AFM procedures for each model aircraft:
 Ensure the gust lock is OFF prior to starting engines (not applicable for G650)
 Check all flight controls for freedom and correct movement prior to taxi/takeoff
 Confirm the elevators are free during the takeoff roll
If you have questions or comments regarding this communication, please contact Customer Support at
800-810-GULF (4853) or 912-965-4178, by fax at 912-965-4184, or by electronic mail at
[email protected].

[mutt]

ALL-MOL-14-0015 on June 13, 2014 That came out within days of the accident.

[Old Boeing Driver]

MAINTENANCE AND OPERATIONS LETTER
August 18, 2014
ALL-MOL-14-0024
FLIGHT CREW OPERATIONAL INFORMATION
TO: All Gulfstream Operators
SUBJECT: Flight Controls (ATA 27) – Gust Lock System

Must have been a follow up. Sorry.

[Astra driver]

Mutt,

No, this MOL is different from the one issued in June and emphasizes that the throttles and/or Auto throttles may still be engaged when the Gust Lock is engaged.

[stilton]

I imagine this aircraft is equipped with hydraulically boosted flight controls.



So why does it even need a gust lock ? snubbing (lock-out when not powered) is a normal function of a powered flight control.

[MotCap]

Stilton;

The G-2 thru 550 flight control systems are all very similar, operating on the same G-2(G-1159) type certificate developed in the mid 60's.

They have what Gulfstream calls 'manual reversion', which allows to operate the flight controls with 'old school', cables, pulleys and bell cranks, with no hydraulic pressure in the flight control system.

On engines start up you release the flight control lock prior to start, and as the first engine spools up when pressures reaches a certain number the hydraulic boosted flight controls come in to effect.

At the conclusion of the flight, on engines shut down, when the hyd press drops to a certain point you can feel the hyd flt controls cut off, and you are back in the 'manual reversion'. All the flight controls can be moved from the cockpit, or on the outside by the wind. The rudder, and occasionally the elevator, are the most easily damaged if the gust lock is not engaged during high gusty wind conditions.

Thank you for your question .. I hope I provided an understandable reply.

MotCap

[Astra driver]

Just to Clarify, Gulfstream models 2 through 5 do not operate under the same Type certificate.

GII and GIII did share the same G1159 type, but GIV and GV have their own separate type certificates.

That being said many of the systems including the hydraulics and the flight controls are very similar between the 4 models, so Mr Cap is correct in his explanation of the flight control system.

[stilton]

Thanks for the explanation MCap.


We had the ability to go to manual reversion with a loss of hydraulics on the B727 though and no gust lock required, controls were snubbed with no pressure. I imagine the 737 is the same.



I realize the flight control systems are probably quite different although the G650 has no gust lock so they must have found a way to secure the control surfaces when needed.


Best wishes.

[galaxy flyer]

The G650 is all FBW and hydraulics, no manual reversion, no cable connection.

GF