[Avionics Today 10-07-2015] Oman Air is using Performance Based Navigation (PBN) to simplify approaches into an airport with one of the most challenging terrains in its network, thanks to new procedure work performed by Hughes Aerospace and Honeywell. The national airline of Oman is currently flying the first Area Navigation (RNAV) approaches to be deployed in the region at Khasab Airport.
The Khasab Airport runway where Oman Air is now flying RNAV visual approaches. Photo: Hughes Aerospace.
According to Ricardo Jaramillo, manager of fleet training for Oman Air, the airport sits at the northeastern gulf coast of Oman with a number of different flight environmental challenges.
"Over the last three years we've started flying our ATR aircraft fleet into this airport, which is quite challenging. The airport is in between a valley, and you have mountains about 3,000 to 4,000 feet high surrounding it as well. The weather is also a challenge with high winds often creating a turbulent environment with a very limited flight envelope to operate within," Jaramillo told Avionics Magazine. The Oman Air fleet manager also noted that the airline is introducing the Embraer 175 into this airport, and the Oman civil aviation authority required a new approach into Khasab to allow them to start flying that aircraft to the airport used primarily for the military.
Hughes Aerospace CEO Chris Baur has been working in partnership with Honeywell Aerospace all over the world to implement PBN procedures and help airlines and operators deal with challenging terrain, reduce approach times and fuel burn during the approach phase of flight. At Khasab, Hughes, which is licensed to develop instrument procedures in Oman, looked to introduce the RNAV Visual approach to deal with the airport’s unique challenges.
"RNAV Visual is a type of approach that we initiated in the United States with the FAA several years ago. The purpose of the RNAV Visual is allowing the [Flight Management Computer] FMC to provide guidance to the pilot for a stabilized approach onto a runway," said Baur. "The challenge for Oman was getting in and out of Khasab and giving the pilots flight guidance; but they didn’t need guidance that was going to take them down to the approach minimums. Oman's pilots were able to land the aircraft in [Visual Meteorological Conditions] VMC, but they just didn’t have a feasible approach. RNAV visual approaches give the aircraft a stabilized and well-defined path to and from the runway as long as the pilots can maintain VMC."
Captain Jean Hersen, an Airbus flight operations expert, presented the benefits of the concept of operations for RNAV Visual approaches during an Airbus Winter Regional Seminar earlier this year. Hersen's presentation cites research from an ICAO Operations Panel working paper on the concept of operations for RNAV visual approaches. According to Hersen’s presentation, the requirements for an RNAV visual approach are for storage and access from a Flight Management System (FMS) database. Also, the pilot of the aircraft must verify the aircraft capability matches navigation requirements for Radius to Fix (RF) leg capability and GPS accuracy. Flight crews can request RNAV visual approaches only upon verification that the required visual meteorological conditions exist, requirements are met, and the aircraft is in a position where the approach can be managed within the flight envelope of a normal approach.
Hughes Aerospace and Honeywell have been collaborating on similar PBN projects at airports in the Asia Pacific region, the United States and elsewhere, and Khasab marks the first deployment of an RNAV visual approach in the Middle Eastern region.
Back in the United States, Honeywell provides major support to such projects by adding the approaches that are coded and submitted to them by Hughes into their available software upload-able FMS navigation database.
"Hughes will develop the procedures and code them and then they send the information to us at the navigation database production group and we will build a navigation database. The database will then be tested. We fly it, we partner with our pilots group here at Honeywell, and we take it to our simulation bench and actually fly it to verify that the procedure flies correctly. We videotape it as well before sending the database to Hughes and the customer that’s going to do the flight validation and testing," Scott Roesch, product support manager for the navigation database production team at Honeywell Aerospace told Avionics Magazine.
Roesch leads a team that updates 1,200 databases for various civil aviation authorities and operators all over the world every 28 days.
"Our database engineers, normally we go back and forth with the procedure designer at Hughes to make sure that the proper line types and path terminators are featured and everything that is associated with building the navigation database and the coding to spec is correct. Once it is error free, we take the ARINC 424 data and convert it into a binary format which is readable and useable on our FMS," said Roesch. "We then build a database which is compatible to the specific aircraft FMS that will use the new procedures and make it available via our website. Whoever the customer is, whether it be the Oman Civil Air Authority, or an airline, we give them authorization to go onto our website, download the database, create it themselves on their specific media type and then they can load it onto the aircraft."
Oman Air is now flying the new RNAV visual approaches at Khasab.
"We were lacking in a proper re-useable procedure, as we were relying on an internally created procedure, where we added some coordinates and we were following certain inputs into the [Global Navigation Satellite System] GNSS, essentially in a make-shift way. It was not an easy procedure so there were constant changes to the coordinates or the waypoints by the airline. But the one created by Hughes is an easy procedure, an easy database and nobody can modify it," said Jaramillo.
The Khasab runway was recently resurfaced to support civil aircraft operations, although Oman's air navigation authority required an instrument procedure for approval to use the airport.
"With a jet aircraft at Khasab, in order to get approval to fly there, we had to have an instrument procedure. This was the tool that gave us the approval because the Oman authority did not want the aircraft to land there without an instrument procedure. The RNAV Visual was the solution, because we did not have the capability for obtaining approval for [Required Navigation Performance Authorization Required] RNP AR," Jaramillo explained.
Khasab could be the first of many RNAV Visual and other variations of PBN procedures introduced into the region, he added.
"This is a start; there is always a starting point and I think now we have changed the mentality of so many people here with the procedure, especially the authority. They saw it can be done and we are getting more confident. I believe there is room for another one here, and perhaps other areas throughout the region as well," said Jaramillo.