When the wind is blowing from the northwest, pilots who have to fly Teterboro, New Jersey’s ILS Runway 6 approach followed by a circling maneuver to line up with Runway 1 have a new resource to make flying this maneuver easier and safer.
Honeywell’s RNP-AR consultancy service, which has been developing IFR required navigation performance-authorization required (RNP-AR) approaches that provide lower minima, now is offering visual RNP-AR approaches to runways that aren’t served by IFR approaches. The first guided visual approach developed by the Honeywell team is for Teterboro’s Runway 1. This can be flown when controllers give the “ILS Runway 6, circle to Runway 1” clearance by flight crew trained and aircraft equipped for RNP-AR approaches.
On May 15, 2017, the crew flying a Learjet 35A on that approach ended up trying to salvage misalignment with Runway 1 at the last minute and stalled and crashed. The problem with this approach and the visual circling maneuver is that after breaking off from the Runway 6 ILS approach at the TORBY NDB, pilots are supposed to calculate the proper turns and descent rate that will align the airplane with Runway 1 and on the correct vertical path to land on the touchdown point and avoid using all the runway.
If pilots don’t start a descent and come in too high, they may end up standing on the brakes to stop before the end of the runway. “That has happened a ton of times at Teterboro,” said Carey Miller, Honeywell senior technical sales manager. “They don’t start down, they land long and hammer the brakes, and deploy the thrust reversers full blast. That’s the noise that [neighbors] hate around there.”
With an airplane equipped with avionics that meet RNP 0.3 (which is sufficient for visual RNP approaches), pilots will be able to fly guided visual approaches to runways that don’t have any IFR approach capability, whether because of airspace and traffic or terrain and obstacle limitations. The approach may be flown on autopilot (highly recommended), and the crew must be trained and receive a letter of authorization (LOA) under OpsSpec C-384 that meets the requirements of FAA Advisory Circular 90-101A. To use the Honeywell approaches, a flight department must first obtain the LOA then sign up for Honeywell’s service to gain access to the Honeywell IFR and visual RNP-AR approaches, which are part of Jeppesen’s nav database. Honeywell can also help operators obtain the LOA.
Visual approaches are nothing new; Honeywell has had these in its FMS for decades, and other avionics manufacturers also offer visual approaches. However, these are just simple straight-in vertical and lateral path guidance with no obstacle clearance provisions. While useful to help make sure that pilots are flying to the correct runway end and to find the airport and runway when visibility is compromised, straight-in approaches don’t help when turns are required to line up with the runway. Flying straight-in to Teterboro’s Runway 1, for example, can’t accommodate long straight-in approaches due to traffic at Newark International Airport.
RNP-AR approaches generally use radius-to-fix (RF) legs, which give vertical and lateral guidance along a circular path. “What has made these so nice now is the RF legs,” Miller said. “That is what has made a difference, being able to fly circling approaches with a curved path.”
The Teterboro guided visual approach (RNAV V Rwy 1) was designed to solve the challenge of how to help pilots safely fly the circling maneuver when cleared for the ILS 6, circle to 1. Teterboro was the first such approach, and Honeywell is about to release visual RNP-AR approaches for Chicago Executive, Jacqueline Cochran (Thermal), Van Nuys, and Scottsdale airports, all on runways that don’t have an existing instrument approach procedure. Some of the approaches involve multiple turns (Teterboro), while others (Chicago Executive) are relatively simple downwind-to-final 180-degree turns. Chicago Executive also was the site of a Learjet 35A loss of control accident while maneuvering to land.
According to Miller, each guided visual approach must begin with a straight-in leg. For the Teterboro approach, the straight-in leg starts with alignment along the ILS Runway 6 approach path, crossing the DANDY waypoint at 1,500 feet, then TORBY at or above 1,300 feet. The guidance then turns the airplane towards Met Life stadium, around the stadium, and lined up with Runway 1. At the same time, the airplane will be descending after TORBY along a 3.5-degree vertical path so it aligns with the Runway 1 VASI when rolling out on final.
Pilots must keep in mind that this is a visual approach, not an IFR approach. And they must program the pilot flying’s FMS with this RNP-AR approach, not the ILS 6 approach. The pilot monitoring should monitor the ILS in raw data, according to the Honeywell briefing sheet. And the RNP-AR approach includes the missed approach, which is the procedure for the ILS 6 approach, ensuring the airplane flies along a route expected by ATC.
The beauty of these “private” RNP-AR visual approaches is that within the constraints for each runway, the designer can create a curved approach that won’t feel radical to passengers. On the Teterboro RNP-AR to Runway 1, the airplane doesn’t bank more than 20 degrees and the 3.5-degree vertical path is reasonably shallow.
A chief pilot for a flight department, who recently flew the RNAV V Rwy 1 into Teterboro, was pleased with the results: "We actually flew it Saturday night after a long day and a line of thunderstorms passed through. Winds were out of the [northwest] gusting to 35 [knots], and the procedure made the circle a non-event," he reported.
“This is [autopilot-] coupled guidance,” Miller explained, “but you’re visual. You’ve got to watch for terrain and obstacles yourself, but it limits overbanking. It brings another level of safely [especially] to night approaches. We build these and code them in the nav database then fly them in the [simulator] and make sure everything is cool. Even though it’s a visual approach, we still do look at obstacles and terrain."
In contrast to maneuvers close to the ground with steep banks and steeper vertical paths, using a carefully designed RNP-AR visual approach “takes the ‘Maverick’ out of the approach,” he said, referring to pilots not having to feel like they need radical maneuvers to make it to the runway end. “Now you’re on a defined path over the ground.”
According to Miller, there are about 150 business jets now qualified to fly RNP AR approaches, but 2,500 or so that could get qualified. Many aircraft with modern Honeywell avionics meet the equipment requirements including those with the NG FMS.