Steep approaches and short runways regularly go hand in hand, and the ability of business aircraft to meet their operational requirements is often key to getting into some of the world’s most desirable locations. Experts from CAE, Embraer, Honeywell Aerospace and Oriens Aviation explain the intricacies of this demanding flying
Among business aviation’s great attractions is its ability to serve airports outside regular airline schedules. Among them, many of these airports are smaller facilities with short runways, and some require a steeper than normal approach to land, because of obstacles or geographic features ahead of the runway, or for noise abatement close to metropolitan areas, while more than a few boast a steep approach to a short runway. Departure generally also requires a steep or stepped climb to clear post-take-off geography.
Fortunately, modern business aircraft are increasingly designed for operations at these more demanding airports. Airframe design, avionics, regulation and training have made the once rare art of the steep approach commonplace, but there is still no space for complacency in this safety-critical environment. So, what flying skills, training and technologies are involved, and just how important is it for aircraft OEMs to provide steep approach capability?
Some years ago, your correspondent experienced the steep approach into Saanen from the cabin of a PC-12 flown by Edwin Brenninkmeyer, founder and CEO of Oriens Aviation, the exclusive Pilatus and Tecnam aircraft distributor for the British Isles, and a Pilatus, Tecnam and Cirrus authorised service centre. Who better then, to describe the piloting requirements of steep approaches?
“A standard approach is 3°; it’s what pilots ‘calibrate themselves’ to, what they are used to,” Brenninkmeyer explains. “On the PC-12 and PC-24 there are options for software-driven steep approach kits for anything over 4°. It sounds like a small difference, but it means big changes in descent rate, the profile you fly, and lots more. There is also the question of whether the approach is VFR versus IFR, requiring a steep approach with an ILS. The enhanced ground proximity warning system – EGPWS – must be considered too, because it will give multiple alerts over excessive sink rate and other parameters during a very steep approach. The steep approach kit eliminates the problem.
“Pilots need special training for steep approaches, especially since different airports have different requirements. London City, for example, has a 5.5° approach, while Sion begins with a very steep 6° from high altitude before reducing to 4°. There are also levels of pilot qualification; if you do an online ‘test’ for Sion, the minima are higher, but if you do simulator training for Sion, the minima are lower, while London City has only a simulator option.”
Back in 2016, ASL proved the Embraer Legacy 450’s ability to operate from the short runway at La Mole-St Tropez. In 2017, the same operator achieved clearance for the steep approach into London City, where the Legacy 500 was already qualified. In a significant move, the Legacy 450 qualification was gained entirely at the FlightSafety International Legacy 450/500 simulation facility in St Louis.
Steep approach has since become an important capability for Embraer, a spokesperson confirming: “The Praetor 600, Praetor 500 and Phenom 300E are certified for steep approach, and customers can select this option during the purchase process or install it via Service Bulletin after aircraft delivery. Previous Embraer executive jets, including the Legacy 600, Legacy 650 and Lineage 1000, also have steep approach certification.”
Embraer says the full fly-by-wire control system installed in its Praetor 500 and Praetor 600 aircraft enables short runway performance and reduces pilot workload. The technology carries over into other Embraer products too, including the E-Jet family of commercial airliners, which frequently operate into London City Airport, and C-390 Millennium military airlifter. The spokesperson continues: “The Embraer Enhanced Vision System – E2VS – technology can also help Praetor pilots during challenging operations. It provides an enhanced vision system combined with a heads-up display, generating better situational awareness and allowing reduced-visibility landings.
“In the Phenom 100EX and Phenom 300E jets, technologies including a runway overrun awareness and alerting system – ROAAS – have been certified to provide pilots with an additional sense of safety. ROAAS engages during the approach phase and, five times per second, calculates how much runway is required to land, comparing those results against the available runway length at the destination airport and alerting the pilot in case of a runway overrun risk.”
Technology and training
Honeywell Aerospace has two primary avionics offers providing protection against runway overrun. Popular with airline and bizjet customers, Honeywell’s SmartRunway and SmartLanding system adds software to its EGPWS in an evolution of its runway awareness and advisory system technology. The product enhances crew situational awareness during landing, on the ground and on take-off, delivering a series of visual advisories.
Thea Feyereisen, Distinguished Technical Fellow – Honeywell Aerospace Technologies, explains that Honeywell also offers a ROAAS; this is a more comprehensive system than SmartRunway and SmartLanding, and has garnered industry recognition.
“ROAAS includes a situational awareness display and aural alerting on approach. It can use information from the flight management system and has its own ‘runway picker’ algorithm, combined with a ‘Golden Runway Database’, and takes into account information added by the crew, like runway contamination, winds and gradients. Then it looks in real time at the aircraft’s energy, providing a predicted landing distance calculated from published tables and based upon aircraft performance. It also looks at what speed and altitude will be across the threshold and then factors in weight, runway conditions and other information. This powers the display and provides an alert if the aircraft is unable to stop on the available runway.” Should a crew find themselves running short on stopping distance, the system will announce ‘Max Brakes, Max Reverse’.
Meanwhile, Honeywell Aerospace is working towards gaining FAA approval for its next-generation Surface Alerts, or SURF-A technology. SURF-A adds runway collision warning advisories, visual and aural, to the runway overrun alerts delivered by SmartRunway and SmartLanding, and ROAAS, as part of a suite of technologies known as Smart X. The systems are carefully integrated to avoid repeated or distracting alerts, while SURF-A uses ADS-B and other data to provide a 30-second warning of the likelihood of a runway collision.
But technology is only part of the story. Pilot training is the essential ingredient that enables safe application of technology and the techniques required to use it. Timothy Schoenauer, Senior Director Global Training Solutions at CAE, notes that short runway instruction is delivered as part of a pilot’s type training. “Pilots learn about short runway operations in their initial training on aircraft including the Bombardier Global 7500. They are also taught performance calculations enabling them to determine airports and runway useable lengths that are not only within the airplane’s capability but within their personal limits. Although we use London City – along with its respective details – for steep approach training, it is taught with an ‘airport agnostic’ philosophy. The steep approach procedure itself does not differentiate between long or short runways. Performed properly, it will allow operations into airports with a steep approach that may lead to a landing on a short runway, provided the length is adequate for a subsequent take-off under given conditions.”
Considering how steep approaches are taught, Schoenauer cautions that techniques and concepts might vary between aircraft types. In general, he says, steep approach is taught with the following in mind, among other elements:
- Thorough approach briefing/ planning
- Stabilised approach concept, speed control, aircraft configuration
- CRM/SOPs (crew resource management/standard operating procedures) with aircraft-specific callouts
- Threat and error management
- Sight picture comparison with that of a normal 3° slope
- Early configuration, proper control inputs and flare technique
- Runway dimension illusions
- Go around mindedness
Noting that, “By and large, if it is steep in, then pilots should likely plan for a steep climb out, while referring to the published missed approach criteria,” Schoenauer adds: “One of the most critical techniques taught for take-offs and landings, but even more so for steep approach with short runway operations, is adequate performance planning and briefing. This starts well in advance of the flight with training at CAE, and continues in the FBO and then into the cockpit. It is also covered in the simulator during practical training.”
Any conversation about steep approaches and short runways with pilots in Europe inevitably includes mention of London City, Courchevel, Saanen and others. Training for specific airport qualifications requires actual airport representation. The editor’s experience confirms that CAE’s Prodigy visuals and acuity are deeply impressive, thanks in part to their roots in the gaming industry, meaning that visual cues for all airport approaches are extremely realistic. The same is true of another forthcoming CAE technology, employing Apple Vision Pro to deliver a high-quality VR training product away from the simulator.
“The application for the Apple Vision Pro is an exciting new product that will prove itself invaluable for training not only for initial courses, but for currency,” Schoenauer enthuses. “Irrespective of the number of steep approaches operationally completed, pilots are required to accomplish recurrent steep approach training every 12 calendar months, while the application could also allow them to apply skills to a specific airport before a trip. Experiencing an approach or other aspect before the actual flight affords a pilot foresight of what to anticipate in advance. One day this, along with what the terrain or airport looks like, the expected sight picture late in the approach or general experience, will give that ‘been there’ advantage.”
Brenninkmeyer adds that very experienced pilots flying the PC-12, or an aircraft of similar capability, might find themselves operating VFR into small grass strips, perhaps with trees or other obstacles at one end. “The scenario likely requires a steep approach, which the pilot can set up as a guide, but it won’t be the kind of approved approach that’s flown into Sion, for example.”
He also agrees with Schoenauer’s assessment that a steep take-off is typically required out of an airport into which a steep arrival was made, adding: “At an airport like Sion or Innsbruck, for example, you have to be certain your aircraft has the performance with its fuel load and weight to make the gradient required by the airport’s standard instrument departure, or SID. If your aircraft can’t meet the SID, then the minima are higher and there is usually a visual circling manoeuvre that precedes the SID, meaning you depart, then turn in the valley, watching the turn radius all the time. You then join the SID further back down the valley, at a higher minimum altitude. In a twin-engined aircraft, of course, the crew also considers whether the gradient can be maintained if an engine fails and, if it can’t, what their ‘out’ is.”
Looking back on the steep approach into Saanen, I recall feeling a little like we were slipping rapidly down a playground slide, with a surprisingly late flare to land, before grazing cows were flashing past to the left and airport buildings to the right. It was a dramatic experience. “Steep approaches into valleys always feel quite dramatic for passengers,” Brenninkmeyer believes. “Jets will typically use their airbrakes, which generate a little more noise, too. Then the flare is more pronounced, so passengers notice the pitch change more. And the runway is typically short, meaning pilots strive for a combination of smooth landing and getting the aircraft down firmly with plenty of runway left.”
Thinking especially about the PC-12, Brenninkmeyer says steep approaches and short runways are not irregular for pilots. The perishable skills required for these more complex operations are practised frequently for real, on top of required simulator and other training. And that’s a point he chooses to emphasise: the need for training. “Well-defined training is required for airports like London City and Sion, but more is required for pilots flying aircraft like the PC-12 into smaller, perhaps grass strips, where there is no defined procedure. Operating safely in this environment requires experience and additional knowledge.”
Indeed, operating steep approaches safely is all about training and preparedness.