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Controls full and free?

Any before takeoff checklist, or acronym such as CIGAR includes “controls full and free”.

So why do accidents such as this still happen? In this case it was Dale Snodgrass, one of the most experienced F14 pilots, very talented display pilot etc…



The NTSB released the final report today and, sure enough, the control lock was in.

Some control locks, such as on the TB20 are very obvious and you can’t put the ignition key in without removing them. But still, it seems odd to not at least stir the stick before lining up.

United Kingdom

IO390 wrote:

So why do accidents such as this still happen?

Because humans.

When I see something like this I’m reminded that guys that are far better pilots than I could ever dream of becoming make big mistakes, so it’s extremely likely that I will make mistakes, and I try to put in place mitigations – like checklists, habits, and consistency.

I also have a “three strikes” rule. If I make three “mistakes” during my prep for a flight or before I push the throttle forward – I stay on the ground. For example, forgetting something on the walkaround, forgetting something at home, missing a checklist item, etc. If my head is not in the game, I need to stay on the ground. It has happened I have to confess, and in hindsight, it was probably a good idea to stay on the ground that day.

Fly more.
LSGY, Switzerland

Yes, because humans!

Mitigations with control locks is to make them extremely obvious (we have a big rudder lock that you won’t miss, especially as in a tailwheel aircraft you won’t even get to the runway if you don’t take it off) and the elevator/ailerons being the seatbelt holding the stick back (you won’t get into the seat).

The Cessna style ones that go through the yoke have a large metal flag that covers the keyhole for the magneto switch.

Control locks that don’t do something obvious that will prevent you from getting the plane moving are risky due to human error, even with checklists.

The trouble is if someone’s in a hurry, they may omit certain things: it’s all very well to say “don’t do that then”, but time and time again, human nature has resulted in these kinds of errors happening, so it’s important to try to design any system to mitigate errors like this. (That he was doing an intersection takeoff rather than the full length may suggest there was some hurry involved).

Last Edited by alioth at 08 Jul 09:03
Andreas IOM

Distraction, and – surprisingly, not an “urgent” flight! The very experienced pilot had just enough time in the new [to him] type to be having fun with it. The SM1019 is a stunning performer, and a lot of fun to fly, but has some odd pitch and yaw handling characteristics, including pitch control force reversal under certain flight conditions. It also does not have a stall warning system, so a stall can creep up on the unwary pilot. The unusual pitch characteristics of this type, and depending upon the flap setting chosen for takeoff, the pitch up after takeoff could be wild, demanding large pitch down control input – not possible with the controls locked. But, at the heart of it, yup, you have to interrupt the flow of your fun to assure that the airplane is actually configured to fly safely! Where I’m sure that this very experienced pilot took very seriously every military or “work” flight he flew, this was a fun flight, so relaxed – too relaxed.

I talked at length with the NTSB Investigator about this accident, as there were likely other factors too, but he told me that at the heart of the cause was failure to remove the control lock, and perform a “full and free” check before takeoff. Even though it might be just a fun flight, or maybe a super fun flight, you still have to treat it like life or death.

Home runway, in central Ontario, Canada, Canada

What a tragedy, it reminds me of highly experienced pilots walking into propellers. Given the pilot’s experience it is really surprising. Am guessing he had extensive aerobatic experience which teaches an OCD like checking of the controls. On the walk around, before engine start listening out for control frictions and how the controls ‘sound’ against the stops, after engine start and before taxi, taxi checks, and before take off. The American practice of pre take off killer items when taking the runway also includes free and correct. Despite this, it seems like every year heavy iron without modern safety systems have take off accidents (usually fatal) when passing V1 and calling Vr they still have control locks. Most modern ‘glass’ on larger aircraft should show control restrictions before take off on the CAS?

Oxford (EGTK), United Kingdom

Do you treat each and every item on the checklist in your mind such that if you miss it you might die?

(Or just something your instructor told you to do before the fun stuff starts)

EGLK, United Kingdom

CEV was the checklist when tugging gliders in France (controls, essence and volets = controls, fuel and flaps) anything else will not kill you, it may damage aircraft & engine though…

Last Edited by Ibra at 09 Jul 19:28
Paris/Essex, France/UK, United Kingdom

It’s a matter of stepping out of the moment as required, and assuring the airplane is correctly configured for whatever is going to happen next. Sadly, in this event, there was a “new toy” factor, and the pilot forgot to “work” while he “played”. He thought it was play time now, and got bit. Different planes have different “killer” items. You must remember what you’re flying, and what you’re going to do to stay one step ahead. Obviously, controls free and correct is the most very basic – totally easy to do, and should be instinctive. For my amphibian, complete extension or retraction of the landing gear will be either three or four distinct control motions. There is an “up” and “down” light to tell you they are complete, as long as you remember where you’re about to land. But, forget one, and you could be “down” but not “locked” – ‘lands fine, embarrassing when you apply the brakes – I’ve been told.

I am philosophically opposed to control locks in the cockpit at all. Either lock each flight control itself, or they did not need to be locked. During the walk around preflight each pilot diligently does, the pilot will see the red flags, and remove the locks/covers. I do like the Cessna Caravan’s rudder lock, a lever at the base of the rudder, applied by hand to lock, and may be manually unlocked, but will be unlocked by up application of elevator. If you managed to taxi to the runway with a locked rudder, you should already have noticed that!

Otherwise, locking the cockpit controls simply means that they cannot move, but the entire flight control system, of which 95% the pilot cannot inspect, is being subjected to loads. I have flown two different Cessnas with flight control system damage that I only noticed once in flight, because the ailerons and elevator were being blown around much too much, and the control wheel was restraining them. An example: https://en.wikipedia.org/wiki/Air_Moorea_Flight_1121 . I use only external control locks. Would external locks have saved this pilot? Uncertain, maybe he would not have noticed flags either.

Sadly, the SM1019 would get airborne with the pitch control locked. I would like to see a design where takeoff were not aerodynamically possible with the controls locked. I opine that many other GA types would not get airborne with the elevator locked in faired position.

Home runway, in central Ontario, Canada, Canada

Pilot_DAR wrote:

I am philosophically opposed to control locks in the cockpit at all. Either lock each flight control itself, or they did not need to be locked.

Why?

For an aircraft that lives outside some sort of lock is essential, unless you want your control surfaces banging around in the wind.

The TB control lock slots into the yoke tube and places a large flat piece of red-painted metal in front of the combined magneto/starter switch. You cannot get the key in, let alone try to take off, with the control lock in.

An external control lock is just waiting to be forgotten. People skip the external checks, or truncate them, all the time. I have never flown an aeroplane that had external control locks, but if I did so regularly then I would be rapidly looking for a way to do without them.

Loads the wind puts on the flight control system while cockpit-locked are no different from the loads on them in flight when the pilot holds them in a particular position in the airflow. It’s what they’re designed to do and surely better than banging around against opposite stops. If the wind (or other forces experienced while parked) are strong enough to damage restrained control systems then your aeroplane probably shouldn’t have been parked there. In any case, I feel the risk of forgetting an external lock is by far the greater one because it’s a risk for every flight rather than just the ones after a hurricane.

BTW the example you posted states external forces as a possible factor, not probable.

Last Edited by Graham at 15 Jul 20:26
EGLM & EGTN
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