When owners take delivery of their new Gulfstream G500 or G600, the pilots who fly these new jets will be able to do something unique, land in poor visibility solely by reference to the enhanced flight vision system (EFVS) image on the head-up display, without ever seeing the runway environment or the ground with their natural vision.
This is a remarkable development, given that the new FAA regulations allowing EFVS-to-land operations were issued in December 2016. Gulfstream is the first to achieve this, and it came as something of a surprise, briefly mentioned in a July 2018 statement announcing FAA certification of the G500 (or as it’s known in FAA paperwork circles, the GVII).
According to the flight manual for the G500, “The demonstrated performance of the installed EFVS Landing System meets the criteria of AC 20-167A for EFVS operations conducted in accordance with 14 CFR Part 91.176(a) in visibility conditions sufficient to safely complete the rollout with EFVS function.”
The AFM continues describing the operational procedures for this capability: “The installed EFVS Landing System on the GVII enables EFVS operations to touchdown and rollout allowing the aircraft to continue descent below DA/DH to touchdown and rollout with the EFVS display image providing the only visual cues for landing.”
While it also mentions that pilots might need a letter of authorization (LOA), opsspecs, or management specs to conduct EFVS operations, there are other questions raised by this capability. For example, what kind of training do pilots need?
Indeed, an LOA is required, and Gulfstream has been working on an LOA template to streamline the process for operators. Training is also necessary, and Gulfstream and FlightSafety International have developed a course for G500 and G600 customers.
Gulfstream was the first business jet manufacturer to certify an EVS (enhanced vision system)—in 2001—which consists of a cooled infrared sensor and a head-up display (HUD) that depicts the EVS imagery. The idea for EVS came from a Gulfstream pilot who flew in the military with forward-looking infrared (FLIR) systems and thought the technology might benefit business jets. “We built a demonstrator in a surrogate piston airplane and found we could identify the airport environment to descend below decision altitude using sensors like infrared,” said Colin Miller, v-p of flight operations.
Gulfstream engineers worked with the FAA, which modified FAR 91.175 to allow descent below decision altitude or height (DA or DH). With the right equipment, pilots could descend 100 feet below DA/DH, greatly improving the rate of successful approaches and landings in poor visibility.
“We’ve been involved with the FAA in particular in creating the EFVS-to-land rule,” he said, “and with that [new rule] we developed technology to enable our airplanes to do that. We were ready when the rule was released to certify our systems. The G500 was first because it was in certification and we bundled it with that.” Follow-on approvals for other models will follow, he added, as well as including other training providers such as CAE.
For training, it turns out that no changes to simulators are required, according to Stefan Eling, Gulfstream chief pilot, advanced concepts and technology. Essentially, the equipment in the aircraft already met the requirements of the new EFVS advisory circular (AC 20-167a), and it just needed validation that it met the requirements. “Validating the current design complies with the certification requirements of the new operating rule,” he explained.
In the G500 and G600, the HUD is a Rockwell Collins system, and the entire system is designated EVS III. The G650 and late-model G450s and G550s have EVS II, and models before that EVS I. Gulfstream is working on EFVS-to-land for the EVS II and I systems, according to Eling, and has developed a certification plan that has been accepted by the FAA.
For testing of the EFVS Landing System on the G500, Gulfstream pilots flew about 50 approaches, demonstrating that the system helped pilots safely land and roll out without using natural vision to see anything outside other than the EFVS imagery on the HUD.
“We chased the weather,” said Eling. “We would wake up at 2 a.m. and take look at the weather forecast and try to find the worst-possible visibility on the Atlantic seaboard.”
Both Eling and Miller have flown the system, although Miller wasn’t testing it as part of the certification program. “I’ve flown a number of very low visibility approaches,” said Eling, “and the performance [of] the camera system that’s in the airplane is outstanding and gives a compelling picture to the pilot that makes it clear that the approach lighting system and the runway touchdown zone environment is very visible. It is a great benefit to operators.”
“It’s clear to me that I can use the infrared image alone,” said Miller. “There is plenty of acuity and great spatial detail.”
While the operational limitation for the EFVS Landing System is 1,000 feet RVR, Gulfstream pilots have tested to much lower visibilities. “I think there’s definite potential for the limit to drop,” he said. “As systems continue to evolve and we work with regulators, there is potential for a lot more. It’s a pretty awesome capability. It’s one of the compelling reasons to operate these aircraft, to be able to go where you want to go when you want to be there.”