Pilots can be excused for not recalling from their initial type-rating training a dedicated session on steep approaches because if they’re discussed at all, it’s typically a way to spend leftover time in the sim following the completion of a required session.
Unless they happen to be seeking approval to operate a new-to-you aircraft into a particular airport, that is, or for a company that flies into such places regularly. Perhaps that’s because pilots don’t necessarily think of these approaches—until one presents itself in the course of a trip, with conditions that compound the facts of a particular airport. But they feature in accident scenarios often enough to deserve special attention.
So, what is the training required, what approvals are necessary, and—most importantly—what do pilots need to know to fly safely in and out of these unique and challenging airports?
It’s confirmed in FAA and EASA accident and incident reports that steep approaches introduce an increased risk of a hard landing or runway undershoot owing to the high descent rate. The risk can be mitigated through pilot awareness and type-specific training. And even if pilots aren’t working for a specific operator that requires the training, they can still ask for it. Then it’s up to them to apply the techniques of a stabilized approach to these unique scenarios.
On Steep Approaches
According to the International Civil Aviation Organization (ICAO), a steep approach is one having an angle of 3.5 degrees or more. The FAA defines it as one that's more than 4.5 degrees, per Advisory Circular 120-118. That’s because those less than 4.5 degrees generally don’t trigger special operations or present a significant amount of increased risk—and this captures most of the steep approaches to airports generally served by turbine-powered business aircraft.
However, once above 4.5 degrees, the objective hazard increases enough to trigger a requirement by most civil aviation authorities (CAAs) for specialized training and approval to operate. An OEM must conduct an operational evaluation (OE) via a CAA to demonstrate the aircraft’s ability to perform the approach in a stabilized fashion. According to Timothy Schoenauer, senior director of global business aviation training solutions for CAE, “Once the OE is completed, then the training provider must receive approval on courseware and curriculum, then train and qualify their instructors and examiners in order to deliver customer training.”
Pilots need to determine next whether the customer in question is operating under Part 91, 135, or 121. And are they flying under U.S., Canadian, or European regulatory guidance—or elsewhere in the world? It turns out that it makes quite a difference.
The airport that many U.S.-based pilots call out for a steep approach is Aspen-Pitkin County Airport (KASE). The airport features an RNAV (GPS)-F approach that possesses a final approach segment at an eye-watering 6.49-degree slope, more than twice the steepness of a typical 3-degree ILS final approach segment. Looking at the terrain surrounding the airport and along the approach course, it makes sense.
“During recurrent I ask to do the Aspen approach after our 61.58 session is completed. It’s not required but it is something I ask for since I go into Aspen a few times a year [in the G650],” said one captain for a Part 91 client flying a Gulfstream G650 and a GIV based on the East Coast.
That’s typical of those pilots AIN surveyed—and Aspen draws attention for good reason: Its lessons translate around the globe to similar fields in mountainous locales.
“We did Aspen-specific training during one of our recurrent sessions,” said Tom Reed, captain for a Dassault Falcon 2000LX flown under Part 91. “This was not specifically the ‘Steep Approach Training’ that is an independent course offered by some groups. We performed the approaches using AFM procedures to configure the airplane for the approach so the EGPWS didn’t trigger and neither did ‘sink rate.’ As a small Part 91 operator, our SOP isn’t so specific to prescribe operations at certain airports—ours is more general to operational conditions and limitations.
“Our agreed-upon procedure for Aspen is to fully configure by the time we reach Red Table [VOR]. That is, flaps and slats are out, gear is down, and we only have full flaps to extend once the descent begins. This gives us stability and the drag we need to get down the path without using the airbrakes.
“We [also] practiced balked landings just moments before touchdown. This required more finesse and crew coordination as the terrain was very close. We had to decide whether to go right or left, how to remain clear of terrain, and how to keep the speed and configuration safe while not increasing the turn radius beyond the geographic (granite!) boundaries of the valley. The high altitude and temperature contributed to the challenge.”
More Mountain Challenges
Founder of Ortega Aviation Services and designated pilot examiner Kirby Ortega has flown a wide range of turbine equipment—from Cessna Caravans to Citation Xs—around the world. He draws from that experience to train pilots on both standard stabilized approaches as well as the edge cases presented by airports such as Lugano in Italy (LSZA) or Saint Barthélemy Gustaf III Airport (TFFJ) in the Caribbean.
St. Barts, being located in a French overseas collectivity, requires a specific approval to fly in to. “You have to pick up a French instructor in St. Martin,” as Ortega recalled. But it was worth it to learn the famous approach to the 2,119-foot runway.
When working with new Citation pilots out of OAS’s base in Wichita Dwight D. Eisenhower National Airport (KICT), Ortega doesn’t have to fly too far from the flatlands to find the places often requested by pilots for additional experience. He’s had several new Mustang pilots take him up on the chance to fly to Aspen, or to Telluride, Colorado (KTEX).
“Assume we’re going into Telluride on a hot day and I look at the chart, at a given weight and temperature, I still have to meet the climb gradient,” said Ortega. “I also look at maximum brake energy, if I land at a higher weight.”
That’s one of those charts that a lot of pilots don’t recall, or forget it exists after training. Since covering FAR 91.103 (b)(1), preflight action, is relatively broad—and the only requirement to cover for the check ride are the performance figures in the aircraft flight manual—Ortega said, “There is nothing else in there about climb requirements, first, second, third segment, and so on.”
So, he gives pilots the following scenario: Can you accept an IFR clearance, and adhere to the published departure procedure, such as that at Eagle, Colorado (KEGE), or Aspen, which has a serious climb gradient required?
“If it’s a great VFR day, you don’t have to accept the [departure] procedure—and the Mustang can barely make it at 8,000 pounds (maximum landing weight) and at 97 knots V2…if it’s a 500-foot ceiling, knowing you don’t have the single-engine climb gradient, will you accept the IFR clearance?”
He’ll then push the pilot in training further if they say yes: “So, we’re going to go, and the PIREPs are now coming in for light to moderate rime ice on the approach, or maybe there is going to be turbulence.” What choice does the pilot make now?
It all boils down to understanding risk management in the discussion on performance. Ortega also calls out the many tools available within apps, specifically ForeFlight. It now has runway analysis with a nearly animated picture of how it looks, for one. That picture during the preflight briefing is definitely worth a thousand words.
Pilots can also reference any “Steep Approach” supplements for the platforms they fly if there is a specific set of operational guidance provided by the manufacturer—as Textron Aviation (then Cessna) provided for the Mustang. These are found in the back of the AFM if they exist for a particular airframe.
London City Calling
While the Gulfstream captain speaking to AIN often flies into the United Kingdom, the airplane isn’t approved for London City Airport (EGLC) because of the field length. The modest strip on the Thames in central London recently increased its usable length to 1,199 meters/3,934 feet in takeoff run available (TORA)/landing distance available (LDA), and its approach slope now measures 5.5 degrees (it was once a stout 7.5-degree angle). The UK CAA requires authorization to fly in—it's the only airport in the UK with such a restriction.
Though out of reach of most jets above the light segment, the airport fits within the capabilities of the Pilatus PC-24, Mustang, certain Falcons like the 8X, and Beechcraft King Airs—not to mention a host of other single-engine turboprops.
Bucket List Adventures with Purpose
Toncontín Field (MHTG) in Tegucigalpa, Honduras, has traditionally been reserved for a captain’s approach for Part 121 carriers, because of both the approach slope and the runway length. When we visited for a Cessna Caravan demo tour in 2006, the runway (2/20) was still only 6,112 feet long, with the approach slope to Runway 2 made significantly more hazardous by the hillside infringing upon the glide path. Work completed in 2009 extended the runway’s total length by 984 feet, with a usable portion now of 6,631 feet.
The approach demands attention—especially for the American Airlines Boeing 757s that used to regularly land there. But as of Dec. 15, 2021, most international carriers have moved to the newly opened Comayagua International Airport (MHPR) located 43 miles from Tegucigalpa on the Palmerola military air base.
Tegu’s Runway 2 was once served by a VOR approach with a 3.2-degree nominal “glide path” from the VOR—which dragged the aircraft over the roughest terrain. This was supplanted in recent years by RNP approaches (NORTH and SOUTH versions) that allow for a curving arc along a valley to the final approach segment and a 3.5-degree approach path. The RNP approach to Runway 20 looks a bit less daunting on paper, at 3.5 degrees as well as requiring crew and equipment authorization.
Also offering up challenges to pilots: Innsbruck, Austria (LOWI). The localizer approach with DME into Runway 26 commences in earnest at 18.2 DME with the glide path to the MDA at 3.8 degrees. Into Runway 8—essentially a localizer approach to a visual—it’s even steeper at an 8.2-degree slope.
At perhaps the pinnacle of destinations that pilots fantasize about and simulate flying into, there’s Paro, Bhutan (VQPR)—though most pilots will never get the authorization to fly there in real life. Paro International Airport makes for an eye-opening exercise in the sim, and Reed found value in the scenario, though it wasn’t for any authorized purpose.
“Airport elevation is 7,332 feet msl. The Falcon was positioned on Runway 33, and the sim instructor set up a V1 cut. Once airborne, we turned right to follow a valley that then curved left and upward. We elected to leave slats/flaps 1 without retracting them after takeoff. The challenge comes in that the valley not only narrows but the floor ascends. This makes climbing imperative. But you’re single-engine, and the challenge is to turn around in the ascending valley and return to Runway 15 to land.
“So you hug the right edge of the valley, monitor your speed and AOA, and prepare for the turn-around. You must keep your speed low to keep the turn radius tight, but you can’t stall in the turn. It takes gentle, shallow banking and finesse on the throttle to make the turn. Then, once the turn is complete, you immediately begin configuring for landing so you don’t get too fast in the descent back down the valley. Finally, you hug the right edge of the valley at Vref to be properly positioned for the left turn to landing.”
Setting Standards on Stabilized Approaches
The Citation Jet Pilots Association sought to address the issue of runway overruns—a direct result, often, of any unstabilized approach, not just those coming off of a steep descent path. To tackle this, it set up a partnering program with FlightSafety International in Wichita to utilize its sims to put CJP pilots through their paces as guinea pigs—and lead them to pledge to commit to stabilized approaches in everyday practice.
And that’s the heart of the solution for pilots when confronted by a steep approach scenario—to consistently apply the same descent planning and gates at which the aircraft must be configured and in a steady state:
- The aircraft is on the correct flight path—and if the sink rate is more than 1,000 fpm because of the approach descent angle, that specific sink rate must be briefed.
- Only minor changes in heading and pitch are required to maintain the glide path.
- Airspeed should be held to Vref and no more than plus-20 knots, and no lower than Vref-minus 5 knots.
- Appropriate power settings are in place, and all briefings have been conducted before reaching 1,000 feet above the field elevation in IMC, and 500 feet in VMC.
In addition, said CAE’s Schoenauer, training elements may include “deploying drag-devices like spoilers on approach with full flaps, [and determining] what that approach angle looks like from the pilot’s seat—it is quite different than a normal 3-degree glide slope…This is a factor for the landing flare and landing illusions.”
And while these are some of the important elements that need to be addressed in specialized training curricula, the airport itself is also critical, along with weather conditions. “When you add normal weather conditions to a non-normal approach to landing, particularly after an Atlantic crossing, for example, where the crew is fatigued, it is a high-risk maneuver for pilots,” said Schoenauer.
Use of high-end visual systems such as CAE’s makes a substantial difference in training. “We work with operators on new approach requests to ensure real visual airport modeling to assure every detail such as buildings, airport markings, and terrain [is] taken into consideration,” said Schoenauer.
For pilots seeking to mitigate the risk, that realism—along with the training itself—pays off in increased confidence and safety.