The Kenya Air Force’s Most Outstanding Engineering Job of the Last 50 Years

KAF_F-5_Jet2

By Roy Gachuhi

Warrant Officer II Luke Kangogo Kittony was in the F-5 Engineering Squadron at Laikipia Air Base, Nanyuki when an F-5E jet crash landed on the runway on a rainy afternoon. The pilot successfully ejected but the plane suffered such severe damage that Northrop, its manufacturer, recommended it be dismantled, crated and flown back to the factory for rebuilding. But the Air Force decided to rebuild the plane at home and it fell upon Kangogo to lead the effort. It was a total success and history was made; F5E tail number 909 became the only fighter jet to be rebuilt outside the factory and Northrop itself applauded the engineering feat. Below, WOII Kangogo tells the story:

This aircraft was being flown by a gentleman known as Capt ABA Mohammed. He was one of the line pilots in the F-5 squadron. On that particular day, it had rained. Due to aquaplaning – a situation where a film of water forms between the tyres and the surface, degrading the braking efficiency of the aircraft – the plane skidded on the runway.

Capt Mohammed had difficulty controlling it and it burst a tyre and veered off the runway. I believe it was to the right side of the runway and it went quite some distance, some 30 to 40 metres away.

The aircraft dug into the dirt and the aircraft suffered severe damage in various areas. Most of the damage was on the right wing. It also ripped off some of the panels. The pilot ejected and by God’s grace, he survived. It was very, very dangerous to do that. Thereafter, we as engineers had nothing else to do but to recover the aircraft. We towed it to the hanger and parked it in a corner awaiting a decision.

Now, aircraft are just like any other machine. Some of the parts needed to get it to work are not always readily available from the manufacturer. You can be put on a long wait. To keep things going in the hanger and your aircraft flying, we take some of these parts from other grounded planes.

In airman’s slang, it is called robbery. After 909’s crash, we used to rob spares from it to service other aircraft in the squadron. This plane was robbed until it was just a skeleton. And there was no documentation. If a part was missing somebody reflexively said ‘just get it from 909’. All good parts were robbed from it.

Then came a time when a decision was made by higher authority that this aircraft be brought to serviceable condition. Northrop, the manufacturer, was invited to come and assess it. I believe there was even a representative from the US Air Force. They concluded that the aircraft was irreparable here in Kenya. They recommended that the aircraft be dismantled and crated and flown back to the Northrop factory for repair and testing thereafter and then flown back to Kenya.

The reason why they recommended that it goes back to the factory is because a lot of parts were robbed from this aircraft. They couldn’t even take inventory to determine what was there and what was not. Secondly, there was the damage to the aircraft itself. The damage that it sustained after going off the runway, especially on the right wing, was quite extensive.

In their assessment, the aircraft had to go to the factory because it required a lot of parts to be machined before being refitted into it and then being subjected to a jig. This is a process through which an aircraft is put to ensure that both wings are on the same angle of attack. They said there couldn’t see an alternative to this.

But General Mahmoud Mohammed made what I think was a very bold decision. Some people thought he did so out of ignorance, not being an aviator himself. He was an army man, an infantry soldier who before becoming Kenya Air Force Commander was the deputy commander of the Kenya Army.

But I think he had both common sense and a sixth sense that it could be done. It ended up being an extremely proud moment for me and the Air Force and a surprise for the manufacturer.

The decision to rebuild 909 was seven years coming. The jet crash landed in 1980 and the order to rebuild it did not come until 1986. Meanwhile, it became the “store” from which parts to service other planes were obtained.

In 1983, I had been sent to the US on a course one of whose disciplines was sheet metal aircraft structures. It dealt in aircraft structural technology. It was an extensive course where participants were building aircraft in the training school based in Illinois. Thereafter I did my practicals at Williams Air Force Base in Arizona.

I was in a class of 15 students from about 15 countries, including the US itself. I emerged the top student. In Arizona, they nicknamed me the Doctor of Sheet Metal because whenever there was a problem, I was every student’s reference point.

A confidential report was made and sent to the Kenya Air Force. On getting it, Gen Mohammed is said to have remarked: ‘If Kangogo can lead people from all these 15 countries including America itself, why can’t he repair this aircraft that is supposed to be taken back to USA? He was leading them, why should it be taken there?’

That was the genesis of the decision to rebuild 909 at home. It was then decided that I be exempted from all military duties for one year to repair the aircraft. I was also given a free hand to choose three technicians to work with; I chose Corporal Martin Warare and Senior Private Aron Kiprotich and Senior Private Malla.

My crew’s first act was to take a complete inventory of the aircraft; we listed every last missing part down to the last rivet.

After this, I decided: ‘Let us start doing the repair first’. We didn’t have the machines in the Air Force to curve the metal and form certain shapes of the skin as required. So I used to cut them into size and take them to Kenya Airways and form them and return to Nanyuki, fix them, measure another one, form, return to Nanyuki and on and on like that until Kenya Airways started developing an interest in me.

In fact, even before my contract had officially run out, Kenya Airways had already given me a letter of appointment. But I served out all my remaining years at the Air Force and when time to leave came, I departed honourably.

The relationship between the Air Force and Kenya Airways was purely on trust basis – there was no contract in black and white for this job. The airline boss of the sheet metal shop where I obtained my materials was an engineer called Sokhi Khalil, a great gentleman. Whatever I needed, Khalil’s stock answer was “no problem.”

There is a very strong member of the wing which is called a spar. It is the one which connects the wing to the body of the aircraft. That is where all the forces act upon. The spar is the one that takes the entire load. When you put the engine or any of the items that hung on the wing it is the spar that transmits that load to the body of the aircraft. And if it is weak, or if you repair it wrongly, then the wing will definitely fall off in mid-flight.

The one that KAF 909 broke in the crash was called a 66 per cent spar. I looked at the engineering drawings from Northrop on how to repair a spar. Then I went to Kenya Airways to buy those thick metal parts and I took them back to Nanyuki.

I cut them to size there and then started bolting. For those we use special fasteners, not rivets; rivets are only used for the skin to the body. These are special fasteners to attach the wing to the body of the aircraft.

After repairs were done, the crew started installing the parts that had been robbed from 909 before proceeding to the testing phase, starting with the hydraulics.

We have a huge machine which is called a hydraulic rig. It pressurizes aircraft and pumps it into the aircraft system the same way the aircraft engine pumps. It pumps at the rate of 3000 pounds per square inch. It is very powerful. If there is a leaking pipe, it can spray and even rip off another aircraft part because of that pressure.

We started slowly, like say 10 psi, and only so very gradually went on increasing the pressure, all the while looking out for leaks. When any such were seen somebody would shout: ‘Stop! Stop! Stop! Hydraulic is leaking from somewhere!’ We would run there and gaze – ‘Arh, yes! A pipe is missing!’ We would then go to the illustrated parts catalogue and thumb through it – pa! pa! pa! Yes, here! Got it! We would order it and fix it!’ It was a totally absorbing thing.

For those parts that were taking time to procure, 909’s crew robbed them from other grounded aircraft, this time making sure we documented it. We maintained a book where technicians entered data indicating that ‘so-and-so has robbed this part from this aircraft on this date’, and then wrote what is called a shortage level. They then put a label and tagged it to the place where they had robbed the part so that anybody passing could clearly see that ‘arh, this was robbed by so-and-so.’

Our biggest challenge was the electrical area. Unlike hydraulics, electrical currents have no leakages. The only way one could tell faults was by operating the various surfaces and following a wire from end to end when an instrument selection from the cockpit yielded no response. It was extremely time consuming.

After ascertaining that all the control surfaces were working okay, the next thing was the engines. The engines of course, had been robbed. The good thing with engines is that they rotate within the fleet; you can remove one to service another one because they are all the same.

Our crew got overhauled engines and installed them on 909. Then we started testing the systems all over again using the engines, not the rigs. Running the engines, of course, could not be done in the hanger because of the extreme noise levels.

Let me tell you one thing: after each and every step you take successfully, you are overcome with joy and satisfaction. It is like your little baby, when you first see her standing up like this and you exclaim: ‘Yeaaaa!’ You celebrate!

The first time we rolled the aircraft out of the hanger to go for engine run, ooooohh! It was a big day in Laikipia! Everybody came out to say: ‘Is that 909? Even the Base Commander, Brig Humphrey Njoroge, stopped whatever he was doing in his office to come and see for himself.

It was like a new baby. There was lots of excitement all around. It was like the whole base had come to a standstill just to see 909 rolling out once again. It was wonderful.

909 was rolled to the place where we were to do the engine run. It is far out at the runaway. We started running the engines, one at a time, exactly as we had done with the rigs, very, very gently at first. It starts with an idle run, just like you idle your car engine.

We let it idle for some time, all the while monitoring the systems: any leak? No. engine instruments, okay? Yes. Everything else okay? Yes. Then we started increasing power – little by little until we went full blast, that is the afterburner. You see a huge flame coming from the back of the aircraft. In flight, that is when it goes supersonic.

When all that was successfully done, we rolled 909 back to the hanger and then reported to our bosses: ‘This aircraft is now ready for a test flight. Ground crew has finished its work. It is now ready for the pilot.’ That is now where Col Shava comes in. Shava said, ‘I’ll take it!’

On the day that Shava took 909 up, I think everybody at Laikipia Air Base came out to watch her fly. Even people from headquarters came. People came out in all their numbers. People kept saying: ‘909 is going up!’ When it was rolling on the runway to take off, my heart was pumping like this, ‘pa! pa! pa! pa!’

But I knew for sure that everything was okay. When you test everything on the ground and it is okay, there is no reason why it should not work up there. But that human element still seizes you and you feel it. And so you still wonder, ‘will it take off? Will it not? Did I get the angle of attack – actually it is called the angle of incidence – did I get the angle of incidence right when I repaired that wing? This is only done in the factory!’

But I was sure. I knew very well that everything was okay. Shava took off. After one hour and there was no incident, communication was okay with the tower, it came back and did a very fast fly past over the hanger where we were all assembled. Shava made two passes over us, each time dipping his wings on either side of the aircraft and then climbing steeply into the clear skies. It was his sign that everything was okay.

He landed perfectly. I am telling you, I was so happy, everybody was so happy, the base commander, the squadron commander, everybody! And you know what, 909 is still flying today!