Jammed Controls

(Mike Brown) – Jammed controls in flight is the stuff of nightmares. This pilot had his elevator jam on takeoff and gave him and his passengers an unforgettable experience.

The aircraft came to rest backwards from the initial direction of takeoff, just off the runway.

Two friends were visiting for a few days from Cape Town, and I planned a pleasant sight-seeing flip for them before they headed home. The plan was to fly over the Vaal Dam, on to Parys for a meal at the local airfield restaurant, and then back to Vereeniging, from where we’d drive to OR Tambo. It was a bit of a tight schedule, but doable if planned correctly. Little did I know that this would be a ‘day to remember’ because of an entirely unplanned event.

I’m fortunate enough to own and fly my own aircraft. My plane at the time was a beautifully restored 1947 SAAB 91 Safir.

This little beauty was initially a trainer with the Ethiopian Air Force before ending up as a stock list item on a consignment of ex-military aircraft to be exported. It eventually found its way into South Africa where it was rebuilt and sold to this classic aircraft collector. Shortly after the rebuild, a brick wall collapsed on her tail section, but this was professionally repaired.

She was now in mint condition, and sitting outside in her blue and white colour scheme looked a million dollars. Sure, she was little ungainly on those short undercarriage legs, but in the sky, where it matters most, she had light controls and a decent run of speed. Plus, she had excellent all round visibility through those panoramic clear plexi-glass windows – perfect for the day’s sight-seeing excursion.

The first leg, from Vereeniging to the Vaal Dam, and then to Parys was perfect. But lunch at Parys ended all too soon, and it was time to get back to Vereeniging and take my guests to OR Tambo.

The second pre-flight for the day was a bit more casual than it should have been, but I did check that everything moved as it should and gave the usual briefing to the passengers. During the engine run-ups, I again checked full control movements and was satisfied that everything worked as it had countless times before. Everyone was in a jovial mood when it was time to get underway.

There was one other aircraft in the vicinity, dropping skydivers, so I announced that I would wait for all of them to be safely on the ground before starting my takeoff run.

Having been assured that all meat bombs were back on terra firma, I lined the Saab up into wind on the 1,605 m asphalt runaway. I gently increased power to 38 inches of manifold pressure in the turbocharged Continental engine, and the Saab accelerated down the runway, eager to get airborne.

Accident aircraft

Pull back a little on the control stick to unstick her and then let her accelerate in ground effect was my general plan. “Whoa, what is happening?” I said to myself as the nose rose higher than expected. I released back pressure, but the stick would not go forward. “What the Dickens is happening here?” I thought (or words to that effect). Then it hit me. The elevator has jammed, and not in the neutral position, but slightly nose up.

I tried forcing the stick forward without alarming my passengers, but they were too busy anyway looking outside as we climbed at an uncomfortable angle and an ever-decreasing airspeed. A quick check of the control stick in front of the passenger showed nothing causing any obstruction and that the passenger hadn’t frozen onto the controls.

Although the aircraft was rated for aerobatics, there was no way in hell I was going to try to perform a low-level loop! This would have ended up in a classic stall/spin accident instead anyway, and probably be labelled as pilot error, at my expense.

Full power was not the solution, as the nose would continue to rise. The next best option was to decrease the power to lower the nose. “This should increase our airspeed,” I mentioned to myself. Ailerons and rudder still worked, so directional control was ok. I think that’s when the passengers started to realise that something wasn’t quite right, and the initial smiles quickly disappeared.

“We have a control problem,” I told them matter-of-factually. I sounded quite calm and this reassured them. No time to panic. Panic will kill you. I remembered that you could use the elevator trim to control the aircraft attitude. This happened in Durban a few years earlier when a Cessna 172 experienced a jammed elevator on takeoff. The pilot did a complete circuit, returning the aircraft to the runway in one piece.

But, I was in no mind to begin a test pilot course, and elected to rather just use the throttle. I also had no time to use the radio as I was kind of busy trying to fly the aircraft – Aviate, Navigate, Communicate, in that order.

I closed the throttle to lower the nose, and then managed our descent path back down onto the runway with bursts of power and rudder to maintain a flat, wings level attitude. Airspeed was life, but at the attitude the Saab was flying, the rate of descent was high.

We landed fast on the tar with a hard thud. The impact broke the right gear off, while simultaneously the left undercarriage bent. The nose-gear collapsed shortly thereafter.

The Saab skidded off to the right-hand side of the runway and completed a gentle pirouette before coming to rest with the nose just on the edge of the tar and pointing at a 45-degree angle down the departure runway. We had managed to stay within the airfield boundary. Smoke, burnt rubber and hot oil smells intruded into the cabin.

Fearing a fire, I shouted, “Out!” to my passengers. I was surprised how quickly they vacated the aircraft and how soon they were already looking back in at me, wondering whether I was getting out as well or not, while I flicked off switches and gathered the fire extinguisher.

Thankfully, none of us sustained any injuries at all, and I can only attribute this to the strong design of the aircraft itself. Standing back from the wreckage, I could see that the right wing was severely deformed and must have absorbed some of the energy in the landing after the gear collapsed.

Walking to the rear of the aircraft, we all saw that the elevator was jammed slightly up, and wouldn’t budge. In the cockpit, the stick was still centred, and we couldn’t find what was causing the jam. So, we left it for the accident investigator to solve.

Help soon arrived in the form of bakkies, a police vehicle and an ambulance – the team at the skydiving facility had seen the accident and were quick to respond.

I remember thinking to myself how lucky we were to survive, and then wondered how the hell I was going to get my friends to OR Tambo. To make matters worse, their luggage was still locked up in my car back at my hangar in Vereeniging.

Notice the position of the logbook at the base of the stick.

Logbook or…

What caused the jammed elevator?

Initially we thought that either something dislodged along the control cables/pulley system, or something in the cockpit rolled under the base of the control stick and jammed the forward movement.

When I reviewed the photographs, I saw my flight-folio laying at the base and side of my control stick. Could this be the source of our trouble? Normally I place the fight-folio on the side of the centre consol between the seats. Could this have moved when we checked our seatbelts and fallen onto the floor, or did it come to rest here from the deceleration forces of the accident itself?

Another cause of the jam

The aircraft was sold off to another gentleman who was going to rebuild it back to flying condition. Last year, (2020) I paid him a visit just before the aircraft was to fly again, and he and I discussed my little episode of the accident.

He believes that the cause of the jam could be from what he found during the rebuild.

A pin that holds the joystick to the base was found to be loose. This pin cannot be seen during the pre-flight, and he believes that this loose pin came adrift during the takeoff roll. The more I pulled the stick back, the more the stick jammed. We were damn lucky that this did not become a fatal accident.

I know I did a full control movement before takeoff and the controls were free, so if it was the flight-folio that had fallen, or the pin that came loose, then it must have happened when the aircraft accelerated and climbed.

Maybe we’ll never know the exact cause?

Fortunately the recovery of the wreck was not that difficult.

WHAT I LEARNT

  • Don’t panic, fly the plane, and think logically.
  • Identify, Verify and Rectify if possible.
  • Remember the primary and secondary effects of the controls – throttle controls thrust which affects nose attitude.
  • Crashing with wings level onto an airfield is far better than spinning/stalling in by trying to go around on low airspeed and limited controls.
  • Control the crash if possible, you will have a better chance of survival.
  • Get to know your aircraft. Change in pitch with gear and flaps varies from aircraft to aircraft. Go into the general flying area, gain a good bit of height and experiment with jammed control situations and recovery techniques.

Could I have gone around in the circuit balancing power and nose attitude using trim – maybe? But I had runway ahead and was within the bounds of the airfield, so I believe I made the correct decision to get it down as quickly as possible. Before the accident, I hadn’t thought of or tried flying an aircraft only on trim, so I was not ready to try at low altitude.

What do I do differently now? I check control movement/freedom in every conceivable direction during my pre-flight walk around, as part of my pre-takeoff checks as before, but now I add a full and free check after lining up on the runway, just to make sure nothing has moved/snagged or jammed.

I also ensure that ALL objects, even the flight-folio are securely stashed away, and eyeball the options for a forced landing after every takeoff with a jaundiced eye! And before the speculation starts – the Saab doesn’t have control locks!

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