Altimeter 29.82, what’s lowest FL you can be cleared for?
AIM 7-2-3 — Use of Altimeter Settings
“When the local altimeter setting is lower than 29.92 inches of mercury, pilots must add 500 feet to the lowest usable flight level for each 0.10 inch of mercury difference.”
Someone flying at 17,000 with an altimeter setting of 29.82 is at 17,100 pressure altitude.
Someone flying at FL180 is at 18,000 pressure altitude. Thus only 900 feet of vertical separation.
Therefore FL190 (really FL185 per the FAA Chart, but practically speaking 185 isn’t used) is the lowest usable flight level.
What’s a RAT
Ram Air Turbine provides emergency AC power in case of IDG/APU failure
What does the ERJ lose in an elec emer?
Emerg: dome lights half.
Only screens 2/3 PFD and eicas,
IESS
comms
DC fuel pump and injector pumps
inverter with AC stdby bus
Comm 1
nav 1
IRS 1
ccd1
GPS 2
FMS2
MCDU 2
Does the RAT deploy automatically?
Yes. When the airplane loses normal AC sources the RAT will automatically deploy and — after about 8 seconds — supply the AC ESS bus.
How does the RAT work (brief tech description)?
The RAT is an airflow-driven turbine installed in the nose that converts ram airflow (kinetic energy) into AC electrical power.
what is an IDG
Integrated Drive Generator that provides AC power to the electrical system
what happens when an IDG fails in flight?
Theres an ICAS message and the IDG disconnects automatically
When one fails, electrical load automatically transfers to other AC sources. Onside (Respective IDG) Inside (APU) Outside (AC GPU) Cross-side (Opposite IDG)
What happens when RAT comes on?
Latches to AC essential bus and I get back
3/2/2/1: Hyd pump 3a, AC fuel pump 2, Slat channel 2, flap channel 1
No displays come back when RAT is on
ESS tru now allows RAT to power DC system which stops battery from discharging
AC stby bus comes from the inverter
According to the ERJ SOPM standardized Minimum/Emergency Fuel Tables, what fuel prediction at the destination or alternate (as appropriate), would require declaring minimum fuel and emergency fuel. How much time does emergency fuel provide
Minimum fuel provides 2,250 LB = 45 minutes of fuel endurance based upon 1,500 ft AFE / Green Dot / Clean.
Emergency fuel provides 1,500 LB = 30 minutes of fuel endurance based upon 1,500 ft AFE / Green Dot / Clean.
Wake separation
Super
Heavy
757
•Super = 6
•Heavy = 4
•B757 = 4
•Everything else = standard radar (3–5)
