Flight Management And Navigation Flashcards
During climbout on a SID, ATC issues a climb and maintain 17,000. How would you delete a hold down over a specific fix without using the FMC? What affect does that action have on speed restrictions?
ALT INTV (deletes next altitude restriction if the MCP alt is beyond the next alt restriction).
Note: use of ALT INTV does not affect speed restrictions on the FMC LEGS page.
You are in VNAV cruise at FL380, 100 miles from TOD and ATC issues a descent clearance to FL240. How would you initiate an early descent?
FMC:
- Set clearance altitude limit in the MCP
- Select DES page
- Select DES NOW> prompt (LSK 6R)
- Press EXEC key.
How would you initiate a cruise descent when >50 miles from TOD?
1: Set clearance alt limit in MCP
2: Push ALT INTV
Caution: FMC calculates ECON speed for new alt and slows before descent, which may result in a speed that is unacceptably low for current altitude. Avoid use of cruise descent for large changes in altitude.
Are there any additional considerations (anomalies) for the MAX regarding VNAV descents?
FMP predictions are periodically recalculated to account for changing environmentals. These may result in additional computing time and an updated prediction could provide a new path when the aircraft is already in its descent phase.
- Could cause 600-800’ VNAV path discrepancy above or below idle path
- If below idle path, the FMC provides guidance to command 1,000fpm descent until intercept.
- If above, may switch to VNAV SPD, requiring crew intervention to re-establish path tracking.
What does a flashing IRS ALIGN light indicate? How many attempts before FAULT light?
Alignment cannot be completed due to 1 of following:
- Significant difference between previous and entered positions or an unreasonable position entry
- No present position entry
- Excessive aircraft motion during alignment.
Note: if 2 consecutive entries of same position do not pass second internal position test, a FAULT light will illuminate
What are the costs/benefits of a derated thrust t/o and climb?
Lowered EGT and extended engine life, but increases total trip fuel. Used when perf limits and noise abatement permit.
What speed does VNAV command at the all engine acceleration height if the VNAV climb page is not manually programmed and speed intervention is not selected?
- 7 responses!
With VNAV armed for climb phase, it commands acceleration to:
- Last MCP speed (V2) +20 until acceleration height
- Flap placard speed -5 knots
- 230kts or less, when LEF are not fully retracted
- 250kts with flaps retracted
- Active target speed
- Waypoint speed constraints
- Speed restriction associated with the origin airport, whichever is more restrictive
You are on arrival and given holding instructions due to weather. How does entering an EFC on the FMC HOLD page affect arrival fuel?
Entry will help optimize FMC perf computations. Computation of destination fuel assumes departing the holding fix at EFC.
How does the FMC calculate hold available time?
Displays in H + M remaining if destination is to be reached w/in planned fuel reserves as entered on the PERF INIT page.
