Raving Gear

SYNOPSIS

The pilot, who was the sole occupant onboard the aircraft, was on a private flight from Wonderboom Aerodrome to Grand Central Aerodrome. His intention was to uplift two passengers at Grand Central from where they would have flown to New Tempe Aerodrome near Bloemfontein.

The pilot was cleared for landing Runway 35 at FAGC by Air Traffic Control (ATC). According to the pilot as well as the ATC, the landing gear was down prior to landing as well as on touch down.

Approximately 100m after the aircraft touched down the propeller struck the runway surface and the landing gear collapsed. The aircraft veered off the runway on the right-hand side, coming to rest approximately 5m from the runway edge facing in a westerly direction. According to the pilot he had selected full flaps for landing and the flaps were still in the down position when emergency personnel arrived on the scene. The flaps were, however, retracted by the pilot prior to the arrival of the Accident Investigator on the scene.

Evidence of runway damage was found on the inboard section of the flaps, indicated that it was in contact with the runway surface after the landing gear collapsed.

PROBABLE CAUSE

The pilot retracted the landing gear unintentionally by selecting the gear lever to the up position instead of the flap lever during the landing roll, which caused the landing gear to retract and the aircraft to veer off the runway.

The aircraft sustained minor damage during the incident. The landing gear started to collapse approximately 100m after touch down. Several propeller strike marks were visible on the asphalt runway surface to the right of the centre line, resulting in bending of the propeller blade tips. A clear white trail of glass fibre compound could be seen on the runway surface as the aircraft skidded along its belly and veered off the runway to the right. The aircraft came to halt approximately 5m to the right of the runway edge facing in a westerly direction (283°M).

The landing gear selector switch was located to the left of the throttle quadrant just above the pilot’s right knee and the knob was in the form of a wheel.

The flap lever was located on the right-hand side of the throttle quadrant and was in the shape of an aerofoil. According to the first responders (aerodrome rescue services) the flaps was still in the down position when they arrived on the scene. During an interview with the pilot he acknowledges that he retracted the flaps prior to the arrival of the Accident Investigator on the scene.

CONCLUSION:

Considering the on scene investigation evidence as well as the post accident test evaluation of the landing gear system it was concluded that the collapse of the landing gear could not be associated with a mechanical malfunction or defect in the system. Available evidence (deformation of torque tube) indicates that the pilot retracted the landing gear unintentionally by selecting the gear lever to the Up position, instead of the flap lever, during the landing roll.

After realising what he had done, he again selected the landing gear lever to the down position. The electrical circuit already activated the hydraulic system and the hydraulic actuator commences to retract the landing gear, the process was irreversible once the circuit was activated. Once the pilot elected to reverse the process by extending the landing gear, the hydraulic system was unable to overcome the weight of the aircraft and in the process of extending/pushing the landing gear back into position bent most of the associated tubes/rods in the system.

JIM’S COMMENTS:

Three things: Slow down. Slow down. Slow down.

Do I like to retract the flaps once the wheels are on the ground? Absolutely I do. When you raise the flaps you dump the lift and the aircraft sits firmly on the ground. If the wind is gusting there is no danger of getting airborne again. If there’s a crosswind you won’t be dragged sideways across the runway, and if you need to brake firmly you can go for it because the wheels have a decent grip on the surface.

Dumping the lift immediately after touchdown is an extremely good idea, Large passenger jets do it automatically. As soon as there is weight on the oleos, spoilers pop out on the top of the wings to kill the lift.

However there is one leeeeeetle codicil – you have to be very certain that you move the right lever. This is so critical that many instructors and testing officers become rude and unpleasant if you even think of raising anything just after touchdown. They will tell you that you should vacate the runway and stop the aircraft so you can give your full attention to cleaning up.

I can’t argue – they have a very good point, as illustrated by this poor bugger.

And I don’t have a foolproof way of guaranteeing that you will always get it right. All I can say is: slow down and think before raising anything. This is particularly important soon after converting to a new type of RG aircraft, because there is no standardisation as to where the levers are positioned.

Beechcraft are the real diggers in the woodpile. They randomly meddle with the positions of vital controls for no discernible reason. And it’s not just the gear and flap levers that are the focus of their indecision. Two apparently similar Bonanzas can have the positions of the power levers all jumbled up.

At times they get it very right. Some Beechcraft have the manifold pressure, revs and fuel flow gauges positioned right above the throttle pitch and mixture levers, and you think, that is so sensible – why doesn’t everyone do it? But the next Bonnie you fly may have them all mixed up again. They could not be more moronic.

In the December issue of SAF I wrote about an accident caused by Bonanza pilot switching on the high pressure fuel pump and killing the engine when he thought he was retracting the gear just after takeoff. Silly mistake? Yes and no. The two levers are within inches of each other. Even worse, they both require exactly the same action – you have to pull them out and then move them up. This bit of insanity cost the pilot and his passenger their lives.

So what can we do to make sure this type of stupid accident doesn’t happen to us? There is only one answer – slow down and think every time before you move any switch or lever.

WHAT CAN WE LEARN?

  • The more knobs and switches you have in the cockpit the more you need to slow down.
  • Don’t assume that two apparently similar aircraft have the same cockpit layout.
  • Before a flight test check with the examiner how he feels about retracting the flaps after touchdown.

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