In order to successfully accomplish simultaneous or  converging ILS approaches, flight crews and ATC have  additional responsibilities. When simultaneous instrument  approaches are in use, ATC advises flight crews either  directly or through ATIS of the active runways. It is the  pilot’s responsibility to inform ATC if unable or unwilling  to execute a simultaneous approach. Pilots must comply  with all ATC requests in a timely manner and maintain  strict radio discipline, including using complete aircraft  call signs. It is also incumbent upon the flight crew to  notify ATC immediately of any problems relating to aircraft  communications or navigation systems. At the very least,  the approach procedure briefing should cover the entire  procedure including the approach name, runway number,  frequencies, final approach course, glideslope intercept  altitude, DA or DH, and the missed approach instructions.  The review of autopilot procedures is also appropriate  when making coupled ILS approaches.  WAAS was commissioned in July 2003, with IOC. Although  precision approach capability is still in the future, WAAS  currently provides a type of APV known as LPV. WAAS can  support the following minima types: LPV, LNAV/VNAV,  LP, and LNAV. Approach minima as low as 200 feet HAT  and 1/2 SM visibility is possible, even though LPV is not  considered a precision approach. WAAS covers 95 percent  of the country 95 percent of the time.  Note: WAAS avionics receive an airworthiness approval  in accordance with Technical Standard Order (TSO)  C145, Airborne Navigation Sensors Using the Global  Positioning System (GPS) Augmented by the Satellite  Based Augmentation System (SBAS), or TSO-146, Stand- Alone Airborne Navigation Equipment Using the Global  Positioning System (GPS) Augmented by the Satellite Based  Augmentation System (SBAS), and installed in accordance  with AC 20-138C, Airworthiness Approval of Positioning  and Navigation Systems.  As with all approaches, the primary navigation responsibility  falls upon the pilot in command. ATC instructions will be  limited to ensuring aircraft separation. Additionally, MAPs  are designed to diverge in order to protect all involved  aircraft. ILS approaches of all types are afforded the same  obstacle clearance protection and design criteria, no matter  how capacity is affected by simultaneous ILS approaches.  [Figure 4-40]  Precision approach capability will become available as more  GBAS (LAAS) approach types become operational. GBAS  (LAAS) further increases the accuracy of GPS and improves  signal integrity warnings. Precision approach capability  requires obstruction planes and approach lighting systems  to meet Part 77 standards for ILS approaches. This delays  the implementation of RNAV (GPS) precision approach  capability due to the cost of certifying each runway.  There are three general classifications of ILS approaches:  CAT I, CAT II, and CAT III (autoland). The basic ILS approach is  a CAT I approach and requires only that pilots be instrument  rated and current, and that the aircraft be equipped  appropriately. CAT II and CAT III ILS approaches have lower  minimums and require special certification for operators,  pilots, aircraft, and airborne/ground equipment. Because  of the complexity and high cost of the equipment, CAT III  ILS approaches are used primarily in air carrier and military  operations. [Figure 4-41]  Notwithstanding emerging RNAV technology, the ILS is the  most precise and accurate approach NAVAID currently in  use throughout the NAS. An ILS CAT I precision approach  allows approaches to be made to 200 feet above the TDZE  and with visibilities as low as 1,800 RVR; with CAT II and CAT  III approaches allowing descents and visibility minimums  that are even lower. Non-precision approach alternatives  cannot begin to offer the precision or flexibility offered by  an ILS. In order to further increase the approach capacity  of busy airports and exploit the maximum potential of ILS  technology, many different applications are in use.  The primary authorization and minimum RVRs allowed  for an air carrier to conduct CAT II and III approaches  can be found in OpSpecs Part C. CAT II and III operations  allow authorized pilots to make instrument approaches in  weather that would otherwise be prohibitive.  While CAT I ILS operations permit substitution of midfield  RVR for TDZ RVR (when TDZ RVR is not available), CAT II ILS  operations do not permit any substitutions for TDZ RVR.  The TDZ RVR system is required and must be used. The TDZ  RVR is controlling for all CAT II ILS operations.  An ILS system can accommodate up to 29 arrivals per hour  on a single runway. Two or three parallel runways operating  independently can double or triple the capacity of the  airport. For air commerce, this means greater flexibility  in scheduling passenger and cargo service. Capacity is  increased through the use of simultaneous or converging  ILS approaches, which are explained further in the  corresponding paragraphs below.  4-63  CAT II and III Approaches  ILS Approach Categories  ILS Approaches  RNAV (GPS) Approach Using WAAS 