7th Bomb Wing · B-1B Lancer · KDYS

RNAV / GPS Approach Guide

Non-precision GPS approach procedures for the B-1B. Key difference from ILS: use NAV HOLD not APR, and manage descent manually to MDA — there is no automatic glideslope.

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Phase 1 — Critical differences between RNAV and ILS
RNAV / GPS Approach
  • Lateral mode: NAV HOLD
  • PFD softkey: GPS
  • FMS NAV MODE: GPS
  • Vertical: manual V/S descent — no glideslope
  • Minimum: MDA — level off and look
  • No APR button — pressing APR on an RNAV will fail
ILS Approach (for comparison)
  • Lateral mode: APR
  • PFD softkey: ILS
  • FMS NAV MODE: NAV
  • Vertical: automatic glideslope capture
  • Minimum: DH — decision at that exact altitude
  • APR arms LOC then G/S automatically
Most common RNAV error: pressing APR instead of engaging NAV HOLD. APR will arm and sit there doing nothing — the aircraft will fly through the final approach course. Use NAV HOLD for RNAV, not APR.
Phase 2 — FMS setup for RNAV
1
FMS NAV page — GPS mode
FMS → NAV NAV1 [0.000] → ← no ILS frequency needed NAV MODE [GPS] → ← must be GPS, not NAV
  • No frequency to tune — RNAV uses GPS position, not a ground station
  • Confirm NAV MODE = GPS
  • PFD softkey must also be set to GPS
2
FMS FPLN — load the approach
FMS → FPLN DEST: KDYS APPR: RNAV (GPS) RWY 34 TRANS: VECTORS [ACTIVATE?] → YES
  • Select the RNAV approach from the FPLN destination airport page
  • Choose transition — VECTORS if being radar vectored by ATC
  • Activate the approach — final approach waypoints load into the flight plan
  • Confirm FAF and MAP waypoints appear in the FPLN route
3
FMS PERF → APPR — set MDA
FMS → PERF → APPR PG FLAPS --> 17° VREF --> □□□ Kt ← auto-computes MDA/H --> □□□□ ← enter MDA from approach plate LAND QNH --> 29.92 ← update from ATIS
  • Enter MDA from the RNAV approach plate — this is your level-off altitude
  • MDA is not a decision height — you fly level at MDA looking for the runway
  • Update QNH from current ATIS (KDYS ATIS: 269.175)
MDA values vary by aircraft category and approach. Always reference the current FAA approach plate for KDYS RNAV (GPS) RWY 16 or RWY 34. NOT FOR NAVIGATION.
Phase 3 — Descent management to MDA
1
Step-down descent profile
  • At the FAF: initiate descent — set V/S selector to target descent rate
  • Typical descent rate: ~700–900 ft/min at approach speed
  • Monitor altitude against each step-down fix on the approach plate
  • Do not descend below any step-down altitude until past that fix
  • At MDA: engage ALT HOLD — level off and transition to visual scan
Unlike ILS, the B-1B FMS will not automatically level off at MDA. You must manually engage ALT HOLD when you reach MDA or you will bust below the minimum altitude.
2
At MDA — visual transition
  • Maintain MDA in ALT HOLD
  • Scan for runway environment: runway lights, approach lights, threshold markings
  • Runway in sight + landing assured → disengage AP, transition visual
  • Approaching MAP (missed approach point) with no visual → execute missed approach
You cannot descend below MDA without the runway environment in sight. Unlike DH on an ILS, there is no brief window to continue — MDA is a hard floor.
!
ATH cutoff — same as ILS
  • ATH disengages automatically at 2,500 ft AGL — at KDYS this is ~4,290 ft MSL
  • Take throttle manually at that point — hold VREF through the rest of the approach
  • Do not rely on ATH to maintain approach speed at or near MDA
Phase 4 — Full autopilot sequence for RNAV
PhaseAPALTHDGNAVATHAPRWhat happens
VectorsONONON—ON—HDG holds ATC vector heading
Intercept finalONONdropsNAVON—Switch to NAV HOLD — tracks GPS course
At FAFONV/S—NAVON—Set V/S descent rate — descend to MDA
At MDAONALT—NAVmanual—Engage ALT HOLD — level off, scan for runway
VisualOFF—————Disengage AP — land visually or go missed
Phase 5 — Common student errors
ErrorWhat happensCoaching cue
Pressing APR instead of NAV HOLDAPR arms and waits for an ILS signal that never comes — aircraft flies through final"This is RNAV — NAV HOLD, not APR"
PFD softkey left on ILSNAV HOLD tracks nothing — deviation needle shows ILS which isn't tuned"Check your PFD softkey — GPS for RNAV"
NAV MODE left on NAVFMS tries to track a VOR radial, not GPS route"FMS NAV page — what's your NAV MODE?"
Not engaging ALT HOLD at MDAAircraft continues descending below MDA — altitude bust"That's MDA — ALT HOLD now"
Descending below MDA without visualBelow published minimums with no runway in sight — safety of flight"Go missed — you're below MDA with no visual"
Late V/S set at FAFAircraft overshoots first step-down fix altitude"Set your V/S as you cross the FAF, not after"