CAT III LANDING ON A MIRAGE 2000-PART III

CAT III ILS ON THE MIRAGE 2000

   DO READ PARTS 1 & 2 BEFORE READING THIS

My story is about the Mirage 2000 fighter aircraft and flying in the early 1990s. My soft-spoken Base Commander was a man from the old school who would not look outside the Rule Book. I was the Air Force Examiner on the Mirage 2000 aircraft and had devised holding patterns, one-in-ten approaches, ILS stacks, etc., things never heard by fighter pilots before. The book said I could fly in RVR of 1000 metres. One day, it so happened that my Base Commander's boss at Command HQ, the Senior Air Staff Officer (SASO), an Air Marshal, had come down to visit the base and see how we conducted bad weather operations.  

It was drizzling that morning and the weatherman said that we could soon expect zero/zero conditions. The Base Commander shrugged his shoulders and looked rather apologetically at the SASO. SASO looked at me and said, " Air Force Examiner.. ........ ....Chicken?" I replied in a twang with a hint of an accusation, "It's your published order, sir. Override it and we could go." "Done," he said. 

For those who don't know, the Mirage 2000 is the easiest aircraft in the world to fly, but bloody demanding to operate in war, given its multiple capabilities. The Indian Air Force took cognisance of this fact and split the force into squadrons with specific roles. The best aid available on board was the autopilot which could do anything, well, almost. In fact, the very same autopilot is fitted on the Airbus 319 / 320s. I had devised and tested an autolanding system, which I practised in a two-seater by night from the rear seat. Landings from the rear seat at night were not easy-you needed practice to get the hang of it. This was a drawback in the aircraft, in that the rear cockpit had a camera screen that repeated what the front-seat pilot could see through the Head Up Display (HUD) in the front cockpit by filming the HUD. The display was far too bright to see anything at all and had to be switched off. You had to approach the runway by looking through the side panels and aligning yourself with the edge of the runway in the fore and aft plane and the Green on Amber on the AVASI in the vertical plane. When about 50 feet above the ground, you could see the runway lights coming under you, so getting back to the centre line was easy. I would intentionally fly head-down approaches at night, asking the front-seat pilot to take over controls if my approach seemed hairy.

The Mirage 2000 is a tailless delta-wing aircraft and faced a problem common to all delta-wing aircraft; the nose of the aircraft had to be raised fairly high to generate the lift required to come in to land at reasonably low speeds. In fact, the Concorde also had this problem, solved ingeniously by deliberately drooping the nose so that the pilot could see what was ahead. In the Mirage 2000, you had to raise your seat fully and change the display on the HUD to what is called the approach mode, which had a landing-oriented but totally different set of symbols on display. Landing after these two actions then became as easy as in the daytime. Rain was a problem, because, even in a drizzle, forward visibility reduced to zero! The Inertial Nav System generated a synthetic runway to project on the Head Up Display, but this was never to be used as the INS drifted with time. Today, with GPS and TACAN integration with the continuously refreshed Ring Laser INS, there is no problem in using the synthetic runway.

I got the SASO kitted up and into the rear seat quickly enough. As we taxied out, the fog came in and visibility reduced to 30 metres. I handed over controls to the SASO and asked him to taxi out. He coped well because the taxi-tracks were 30 metres wide and he could see the centreline and the grass beyond the taxi-track edges. As we moved further away, visibility dropped to 10 metres and I had to take over controls again. ATC piped in with a warning that RVR was 20 metres and dropping. Without informing the SASO, I switched the ILS on and used the localiser to get onto the runway centreline. I asked the SASO if he would like to take off. He declined, saying, "I can't see anything." I insisted he take off, saying that the aircraft was on the centreline and would stay there for the 450 metres required for take off. In any case, I was there to assist or take over if anything went awry. He agreed and the take off was uneventful. 

We climbed out of all clouding by 9,000 feet. SASO started to throw the aircraft around, enjoying himself. Later, I took him down to 1,000 feet above ground level in a flattish and safe sector and, whilst still in cloud, showed him the ground mapping and safety modes of the multimode radar. I showed him how to distinguish roads from rail tracks, how to assess heights of hill features, what rivers and bridges looked like, etc. He was more than impressed with the quality of the display and what all could be achieved. Soon it was time to get back. I took over controls and said, "See for yourself how this aircraft autolands, sir." 

I got in touch with our local radar and informed him we were doing an auto-ILS and requested back up. I started to slow the aircraft down from 450 to 200 knots, punched the required buttons, raised my seat, selected auto-ILS and changed the HUD to landing mode. I then showed SASO my hands and said, "I won't touch controls unless required."The aircraft auto navigated to the holding point and as my speed dropped below 225 knots, the "lower undercarriage" command prompted me to lower the landing gear. The aircraft had climbed to the stack safety height of 2,600 feet above sea level by then and entered the holding pattern at 200 knots. Since we were the only aircraft in the air, we exited the stack on our first turnaround.

I informed ground radar of our exit and as we approached the ILS LOC beam, the aircraft turned and captured the localiser. As mandated, I called out LOC capture. I then reduced power to hit approach angle of attack(ά) of 13° and maintained it. Soon we were on glide path and the aircraft commenced descent. Radar called out,"You're on glide path and centreline. RVR is now zero in light drizzle. Wind is calm. Recheck wheels down and locked. Acknowledge." The Mirage 2000 has a beep signal that is transmitted on three frequencies at one time, when a button is pressed, but only if the wheels were down and locked. This signal confirms to the ground controllers that the wheels are actually down and locked. Radar, in turn, acknowledged the signal and we were now on ATC frequency on our second radio set. All this while we were in cloud. ATC called us and said that all runway lights and the AVASI (Visual Slope Indicator) were on. We would never see them.

I had selected Radioaltimeter visual warning to 20 feet. As the aircraft silently descended through clouds, radar kept telling us, "On glide, on centreline." My hands were visible to SASO, who said,"Can't see a sausage outside." "Look at the Head Down Display, sir," I added. It showed our glideslope. At 350 feet on radalt, I disconnected ILS glideslope, its minima being 300 feet-not even a Cat I ILS. I kept the last used glidepath on the autopilot and retained auto-centreline control. We were aligned perfectly down the centreline. At 100 feet, radar said, "Approaching our minima, on advisory if requested." I responded, "Yes, please."

He continued,"On centreline, crossing threshold, height should be 30 feet." It was. As the radalt warning came at 20 feet, I throttled back to idle and allowed the aircraft to sink, allowing the ά to increase to 14°. Close to the ground, at 15 feet and less, the air compressed under the large delta wings of the Mirage 2000 tends to cushion its landing. Radar said, "Approaching touchdown." As we touched down smoothly, the autopilot disconnected by default. I just stayed on the ILS line and asked SASO,"Shall we do another one, sir?" He declined. I gently brought the aircraft to a halt and asked for the follow-me jeep. My engine noise and flashing lights were picked up by the follow-me jeep, and I put my 2000-watt landing lights on. This was reflected by the orange stripes of the jeep and we followed him all the way home at a sedate 10 kph. On the long stretch back, SASO waxed eloquent, totally impressed with the aircraft (and the Indian Air Force Examiner?) 

Today's Mirage 2000 has been upgraded radically so that the synthetic runway genuinely shows where the actual runway is. Auto-throttle has not been added.