Navaid Substitution

PRESENTED BY:

Jim Johnson, Honeywell Aerospace

Tuesday, March 24th | 3:40 p.m. – 4:00 p.m.)

International Operators Conference | San Antonio, TX | March 23 – 27, 2015

Navaid Substitution

• Navaid Substitution: Using a suitable RNAV system as a substitute means of

navigation during approaches without “GPS” or “GNSS” in the title. . .

– The radio-based navaid is OTS

– The aircraft is equipped but the receiver is inoperative

– The aircraft is not equipped with a receiver required to fly the procedure

• This presentation is limited to the context of approach procedures

• Using FAA regulations and guidance as a reference

2

What is it?

Aeronautical Information Manual, FAA Advisory Circular (AC) 90-108

Navaid Substitution

• Your aircraft is equipped with

dual FMS/GPS with SBAS

capability (all operative)

• This approach is selectable in

your navigation database

• Your ADF is MEL’d out of

service

• Can you legally fly this

approach in its entirety using

the FMS? 3

Poll

4

Navaid Substitution

• Hold on. . .

5

Correct Answer

Navaid Substitution

• Introduction of GPS as an approved sensor

– FAA GPS Overlay program

• Stand-alone GPS approaches and “or GPS” overlays were in abundance

– FAA began publishing RNAV (GPS) procedures

• Removed the “or GPS” overlay

6

Historical reason for the confusion

Navaid Substitution

• Installation of multi-sensor RNAV systems

– Providing a high level of confidence in position accuracy and continuity

• Procedures coded in the navigation database

• Aircraft manufacturers delivered cockpits without some conventional nav receivers (e.g., ADF)

7

Historical reason for the confusion

We don’t need no stinking ADF

Navaid Substitution

• Your aircraft is equipped

with dual FMS/GPS with

SBAS capability (all

operative)

• This approach is selectable

in your navigation database

• Your ADF is MEL’d out of

service

8

Poll

Answer: No

Navaid Substitution

• FAA AC 90-108, Paragraph 8 (paraphrased)

– A otherwise suitable RNAV system cannot be used for

the following: substitution for the navaid (e.g., VOR or

NDB) providing lateral guidance for the final approach

segment.

9

US regulatory guidance on navaid substitution

Navaid Substitution

• AIM, Section 1-2-3

– Use of Suitable RNAV Systems:

“Pilots may not substitute for the navaid (for example a

VOR or NDB) providing lateral guidance for the final

approach segment.”

10

US regulatory guidance on navaid substitution

Navaid Substitution

• Transport Canada

– AIC 16-08, Paragraph 6, Use of GNSS in Lieu of Ground-Based Aids

“For approaches that are not part of the GNSS overlay program. . ., the PIC shall monitor the underlying navaid for the approach and missed approach track guidance.”

11

Foreign regulatory guidance examples

Navaid Substitution

• France DGAC – AIC A 09/07 - ADF Receiver Carriage in French Airspace

NDB non precision approach: “In France, this type of approach is not published as an “overlay” approach. For that reason it is forbidden to conduct such approach without ADF receiver on board.”

– Technical Guidelines 01- PBN Guidelines for RNP APCH operations also known as RNAV (GNSS)

“Performance is possible using the FMS provided that the VOR/DME is raw data is displayed to check the consistency of the information given by the FMS.”

12

Foreign regulatory guidance examples

Navaid Substitution

• Navigation database procedure

coding and integrity

• Flight check

13

Reason for the restriction. . .

14

15

─ Flight Checked – radio navaid only

─ No procedure coding by regulatory

authority

─ No navigation database integrity

checks performed

Navaid Substitution

16

Poll

Answer: No

• Your aircraft is equipped with

dual FMS/GPS with SBAS

capability (all operative)

• This approach is selectable in

your navigation database

• Your ADF is MEL’d out of

service

Navaid Substitution

• US Part 135/121 operators only

• Authorizes operator to fly NDB and VOR approaches

using RNAV with GPS as a substitute means of

navigation when

– Navaid is out of service, or

– Aircraft is not equipped with ADF or DME

17

Operations Specification (Ops Spec) C300

Navaid Substitution

• Operator must use a navigation data and flyability

validation process

– Ongoing system-wide or procedure specific checks

of navigation data and flyability

– Must ensure nav data used by RNAV system

conforms to the published procedure

18

Ops Specification C300 - Requirements

Navaid Substitution

• Aircraft navigation system accuracy must meet the

following standards:

– RNP 1.0 in the initial, intermediate, and missed

approach segments

– RNP 0.3 in the final approach segment

19

Ops Specification C300 - Requirements

Navaid Substitution

• Navaid substitution guidance varies among different

OEMs

• Regardless of OEM guidance, the regulatory guidance is

clear

• Honeywell is working with OEMs to clarify this guidance

to conform to regulatory guidance

20

Manufacturer Guidance

21

Navaid Substitution

• Operators are required to monitor the underlying navaid on

non-overlay, radio-based approaches during the final

approach segment

– Receiver required for the approach must be operational

– Navaid must be operative

– Approach must not be NOTAMED as “Not Authorized”

– Raw data must be monitored to ensure the FMS is

flying the intended course for the procedure

22

Summary

23

Thank You!