Guy Leitch

Recreational pilots may be forgiven for sometimes thinking that airline pilots have a boring job, flying the same routes, day in and day out, to strict procedures, while maximising fuel efficiency to keep the bean-counters happy.

HOWEVER, EVEN WITH AIRLINE FLYING, there are opportunities for pilots to have a bit of fun and excitement. One such opportunity is the straight-in approach to Hoedspruit’s Runway 09.

The descent and landing into Hoedspruit 09 is interesting because of the short distance from the Drakensberg Escarpment to the threshold. It reminds me of a Presidents’ Trophy Air Race where the organisers placed a checkpoint just 5 nm beyond the escarpment. I know of a number of pilots who admitted to exceeding Vne getting down to the checkpoint.

Despite having been a front-line military airfield for Mirage operations, the 09/27 runway at Hoedspruit is decidedly secondary as it is only 2000 m long and 27 m wide. As an interested amateur pilot, it seemed to me to be something of a challenge for a jet the size of an Embraer 190. In asking Airlink about how they fly the approach and landing, I learned much about airline operations, procedures and limitations.

The day we flew straight into Hoedspruit’s 09 from Cape Town, I was amazed to see the windsock showing about a 15-knot tailwind – blowing from 270, directly down the runway.

‘terrain separation with the ‘Mark 1’ Eyeball’

As a ‘Pappa Charlie’ pilot who regularly descends into Hoedspruit in a piston single, on clear VFR days it’s always fun because I want to stay high over the escarpment, even if only to keep my wife/hostie in the back happy by minimising turbulence. I typically remain at FL095 until past the escarpment at Mariepskop and then put the nose down and descend at about 1500 fpm or more, keeping the power on to keep the engine warm, but also with a wary eye on VNE.

For a jet airliner to descend from FL370 straight in-to Hoedspruit, top of the descent has to be far before the escarpment. For our descent in Airlink’s Embraer 190 there was a layer of alto stratus at around FL150. So the descent would have been at least partially IMC.

To learn more about this, I asked Tammy King, Airlink’s Executive Manager Flight Operations and Head of Training, to tell me how these approaches are flown.

For the descent in CAVOK conditions, with the air crystal clear and visibility all the way to the Indian Ocean, it may be tempting to do terrain separation with the ‘Mark 1’ eyeball. Yet regardless of conditions, the flights remain IFR, as it gives the crew the option to resume IFR in case of diversion, or if the visual approach criteria cannot be maintained.

Tammy explained that the approaches into Hoedspruit are always planned as standard instrument approaches to Runway 18/36. However, the pilots also have the option of a straight-in visual approach to Runway 09. So even for airline pilots, there is clearly a lot of scope left for the crew to decide how they want to get their aircraft onto the ground at Hoedspruit.

Hoedspruit’s (FAHS) layout – showing how much time is saved by using 09 straight-in.

If conditions are VMC and the runway can be kept in sight, once the aircraft is within 25nm of the airport, a visual approach can be requested. For the instrument rated pilots reading this, it is necessary that the cloud base be above the MSA or there has to be “a reasonable assurance that a visual approach and landing can be completed.”

For recreational pilots used to aircraft with basic VFR instruments, it’s interesting to know that the airline pilots on IFR do not have to be able to see the escarpment as the aircraft displays terrain as part of its EGPWS. This relatively modern technology would have been a life saver for the number of VFR flights that started down too early and impacted the western slopes of the mountains. One of these famously took out teenage pop star Gwynneth Ashley Robin and her band in a C210 that crashed into the escarpment near Penge.

The way the Hoedspruit approach works in practice is that, from top of descent, the crew continues to descend under IFR to the Minimum Sector Altitude (MSA). Then they can put the  nose down in a steeper descent once they have passed the Mariepskop radar station on a straight-in visual approach to 09.

The increased rate of descent once past Mariepskop raises the question of how you get an aerodynamically slippery airliner to both go down and slow down simultaneously. Tammy King explains that the challenge of both going down and slowing down all depends on the energy of the aircraft in terms of the speed limits for flaps and landing gear. She points out that a considerate pilot will leave a healthy margin to not put them under strain.

Airlink Chief Pilot Tammy King.

Tammy says that if on the approach, the crew find themselves high after having cleared the terrain, they just slow the aircraft down by powering back and holding the nose up. She explains that the crew then have the option to select flaps while at the lower air speed and thus increase the drag and rate of descent. However, on some approaches with a heavy aircraft, speed brakes are needed. This then gives them the option of putting the nose down to convert the excess height into speed to intercept the visual glide path, even if from above.

I asked Tammy about the effect of the 15-knot tailwind we had experienced and she told me that the E190 is certified to land with a 15 knot tailwind component. (The ERJ135 has a 10-knot limit). Tammy explained that the landing figures are calculated before descent to ensure that all the performance limitations are complied with before accepting a tailwind landing. These limitations are determined by factors such as the landing weight of the aircraft and the friction rating of the runaway.

Airlink has, as standard procedure, landed at airports such as St Helena which have shorter runways than Hoedspruit, and with more challenging conditions, so landing straight-in on Hoedspruit 09 is a comfortably standard procedure. The E190 can easily operate in and out of 2000m at maximum weight. Interestingly, Airlink has had both aircraft types certified to operate on narrow runways, down to a minimum runway width of 20 m, compared to the standard minimum 30m for commercial jet aircraft.

Airlink’s narrow runway approval is important for Hoedspruit as it is also an Air Force Base and there’s ongoing discussion about the proximity to the runway of the runway lights and the above ground cables that feed them. As the runway lights are not frangible (at least not to civilian standards), the effective runway width is thus reduced from 30m to 20m, even though the actual width is still 30m.

Given a tailwind and shortish runway, the important thing when landing is to nail the speed and not float. On my flight the Airlink pilots made a commendably firm arrival and the braking was not particularly severe. Although the E190 has reverse thrust, it was not necessary, and it is not part of the aircraft’s landing performance calcs. Tammy explains that reverse is basically a nice to have when required. The E190 has carbon brakes that operate best at high brake temperatures. She says that the E190 is a very capable aircraft, and is built for short field performance, so only moderate braking is required for landing in 2000m.

Hoedspruit’s (FAHS) radar terrain clearance chart.

I asked Tammy what the downwind limitations to use 09 straight-in are and when they would choose to go all the way round to 27, increasing track miles, flying time and fuel used. She said that they normally use 09 for landing and 27 for departure to save operational costs. The crew will therefore rather use runway 18/36 if 09 is beyond limits for landing. She pointed out that the straight-in approach also reduces taxi distances after landing because 09/27 is significantly closer to the terminal.

Jets have plenty of power and can easily outclimb the Drakensberg escarpment, so 27 is the natural choice for takeoff.

Tammy concluded by saying that it is indeed fun to fly the straight-in approach to Hoedspruit. There are always options available for the crew for cost savings with straight in approaches or shorter routings, but she dutifully pointed out that cost savings will never take precedence over safety.

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