In 1994 Steve Hickok began the initial flight tests that led to development and implementation of the first FAA-approved GPS Rnav helicopter instrument approaches. Probably no one–least of all Hickok himself–could foresee that 16 years later he would be an FAA designee (to date the only one) to develop, test, validate and oversee commissioning of GPS wide area Augmentation system, lateral performance [with] Vertical [guidance] or “Waas LPV” helicopter approaches.
This week his consulting firm, Stephen Hickok & Associates, is at Booth No. 2910 acquainting prospective clients with what it takes to get a private-use Waas LPV approach designed, approved and published. Hickok & Associates, said Hickok is currently the only FAA-approved Waas LPV helicopter approach developer. Most of the 12 clients for whom his firm has obtained these approaches have been medical centers or emergency medical services operators.
Today, the Hickok turn-key service goes far beyond simply laying out an IFR approach, but encompasses construction, approval and maintenance of departure procedures and creation of off-airway feeder routes leading into the approaches. This involves applying FAA obstacle-clearance criteria to the actual terrain along a proposed route and approach, using proprietary Hickok-developed software and highly accurate satellite mapping.
Ed McConkey, an electrical engineer who worked on pioneer satellite navigation for the U.S. Air Force and has years of experience with the FAA, has worked with Hickok from the beginning. He has developed software for defining FAA-required protected airspace, both lateral and vertical, to compute the “obstacle evaluation area” for terrain along a given approach path.
In recent years the FAA has commissioned a number of Waas Lnav approaches for both rotorcraft and fixed-wing, but has not issued Waas helicopter instrument approaches with vertical guidance, McConkey said. “We have taken fixed-wing criteria and integrated them with helicopter performance numbers to obtain ‘user-defined criteria’ as the basis of approach procedures.” These have been submitted to and approved by the FAA.
The challenge, he explained, is to adapt existing Lnav approaches to LPV criteria to achieve lower minimums, approaching or even surpassing those of fixed-wing ILS procedures. Most recently Hickok has been in Switzerland designing and preparing to validate a Waas LPV-equivalent approach to the Interlaken Hospital, using the European Egnos GPS satnav-augmentation system. His calculations indicate that an approach down to 347 feet above the surface would be feasible, but that number has not yet been flight verified.
Hickok says that, as a general guideline, if an ILS approach could be made to as low as 460 feet, a Waas LPV procedure over the same surface could very well go down to 250 feet.
