IFR

Precision vs non-precision

precision approaches:
- using DA: ILS, PAR
non-precision approaches:
- using MDA: NDB, VOR, LOC, LNAV, ASR
- using DA: APV (approach with vertical guidance), including LNAV/VNAV, LPV, LDA+glidepath

Note: APV approaches provide vertical guidance but don't meet the ICAO and FAA precision approach definitions, which apply mostly to localizer and glideslope transmitters.

Frequently used approaches

ILS/LOC
LPV:
- Localizer Performance With Vertical Guidance.
- NOT considered precision approaches.
- Requires WAAS, which provides 7.6 meters or better accuracy.
- usually get you down to 200 ft above touchdown.
- if you're using an airport with LPV only as your alternate airport, you need weather minimums that meet the LNAV or circling MDA.
LP
- similar to LPV but without vertical guidance, the GPS equivalent of a LOC approach
- WAAS equipment is mandatory for LP.
LNAV:
- no vertical guidance, complete with step-down altitudes.

Not so frequently used approaches

LNAV/VNAV: Lateral Navigation/Vertical Navigation
- the final approach course is linear the entire way to the runway (like LNAV), decreasing to 0.3 NM sensitivity when you're within 2 miles of the final approach fix, all the way to the missed approach point.
PAR: Precision approach radars (precision) are used by air traffic controllers to issue guidance to pilots during final approach using radio. These are precision approaches similar to the ILS approach. PAR uses primary radar. It does not require any onboard equipment. (ILS is part of the standard aircraft equipment) The use of PAR in civil aviation has been constantly diminishing.
ASR: Surveillance Approach (non-precision): ATC provides lateral guidance to you using radar to monitor your position. ATC gives you a series of headings and corrections to align your final approach with the runway's extended centerline.
- ASR approaches use Terminal Radar, which means you can only get coordination for these approaches from an Approach Controller, not a Center or Tower Controller. (You won't talk to the tower, but will talk to an approach controller all the way to the ground.)
LDA: Localizer Directional Aid.
- like a localizer, except it's not aligned with the runway. Used in places where terrain or other factors prevent the localizer antenna from being aligned with the runway that it serves.
- uses the same equipment as a standard localizer.
- e.g. Honolulu (PHNL) LDA RWY 26L
NDB

RNP vs RNAV

RNP (Required Navigation Performance) is a type of RNAV, but with requirements:

RNP must include onboard performance monitoring and alerting capability (i.e. RAIM); it will alert the pilot when the accuracy degrades.
RNP must meet a specified accuray at least 95% of the flight time.

LPV vs LNAV/VNAV vs LNAV

	LPV	LP	LNAV/VNAV	LNAV
GPS + WAAS	Yes	Yes	Yes	Yes
GPS + Baro-aiding			Yes	Yes
GPS				Yes

Baro-aiding: Barometric aiding is an integrity augmentation that allows a GPS system to use a non-satellite input source (e.g. the aircraft pitot-static system) to provide vertical reference and reduces the number of required satellites from five to four.

Baro-aiding satisfies the Receiver Autonomous Integrity Monitoring (RAIM) requirement in lieu of a fifth satellite.

V vs +V

The V in LPV, LNAV/VNAV is the "approved vertical guidance".

The +V in LNAV**+V** is the "advisory vertical guidance". Provided by GPS manufacture. "+V" is never shown on a chart. With +V, pilot can fly a constant descent to the MDA (otherwise need to step down).

Load vs Activate an approach

Loading an approach: Adds the approach procedure to the end of the flight plan, but the GPS will still navigate to the destination airport.
Activating an approach: Changes the next navigational fix to a fix in the approach procedure.

Request practiced approach

ME: request practiced approach Stockton ILS 29R with published missed, vector to final

ATC: heading 270, maintain 2,000 until established, cleared ILS 29R approach

Visual approach vs Contact approach vs Instrument approach

Visual approach: ceiling >= 1000 ft; visibility >= 3 sm.
Contact approach: the pilot may deviate from the published instrument approach procedure (IAP) and proceed to the destination airport by visual reference to the surface.
- Similar to a visual approach, but do not need the airport in sight; 1 sm visibility; the airport must have a published instrument approach.
- ATC can't initiate a contact approach, you have to ask for it.
- there's no missed approach procedure
Instrument approach: fly the published instrument approach.

What is "VFR on top"?

"VFR on top" is a flight status that allows a pilot to fly above a cloud layer while maintaining an Instrument Flight Rules (IFR) flight plan. It allows the pilot to select a VFR altitude instead of the assigned one, which can be helpful when flying above or between cloud layers.

Alternate

When Do You Need to File An Alternate?

You need to file an alternate:

if the airport does not have a published instrument approach
if the airport does have a published instrument approach, but does not meet the 1-2-3 rule (1 hour before to 1 hour after ETA, ceiling 2,000+' AGL, visibility 3+ SM.)

Which alternate airport to file?

FAR 91.169 the weather conditions at the ETA must meet or exceed:

precision approach: 600' ceilings AND 2 SM of visibility.
only a non-precision approach is useable: 800' AND 2 SM of visibility.
If no instrument approaches are available: Descent from the MEA and landing must be conducted under basic VFR.

Also need to check the approach plate if the airport has nonstandard alternate minimums.

What if there's no TAF at the destination or alternate?

Check Aviation Weather: https://aviationweather.gov/gfa/#clouds

When can you log IFR approach?

Simulated: down to minimum, DA/MDA.
Actual: only if still IMC after FAF;
- if conditions change from actual IMC to VMC before FAF, to log the approach, you need to use a view limiting device.

What is DIVERSE DEPARTURE PROCEDURE?

A diverse departure procedure is an instrument flight rules (IFR) departure procedure that allows a pilot to turn in any direction from the runway while staying clear of obstacles.

All US airports with a published IAP but with no published DP (no ODP and no SID) meet the Diverse Airport criteria.

Procedure

Cross the departure end of the runway (DER) at least 35 feet above the DER elevation
Climb to 400 feet above the DER elevation before making any turns
Maintain a minimum climb gradient of 200 feet per nautical mile (FPNM) until reaching the minimum IFR altitude

Diverse Vector Area (DVA): allows ATC to provide radar vectors instead of an ODP, while meeting the diverse departure criteria.

What is VISUAL CLIMB OVER AIRPORT (VCOA)?

A departure option for IFR aircraft in VMC.
The pilot visually conducts climbing turns over the airport up to the published "climb to" altitude, from which he proceeds to the instrument portion of the departure.

What is RNAV 1 Performance?

RNAV 1 is a type of Area Navigation (RNAV) that's primarily used in terminal airspace for arrivals, departures, and approach transitions.

RNAV 1 performance requirements

Aircraft must maintain a total system error of no more than 1 nautical mile (NM)
This accuracy must be achieved at least 95% of the flight time
RNAV 1 is typically used for DPs and STARs

What is Cruise Clearance?

The term “cruise” may be used instead of “MAINTAIN” to assign a block of airspace to a pilot from the minimum IFR altitude up to and including the altitude specified in the cruise clearance. The pilot may level off at any intermediate altitude within this block of airspace. Climb/descent within the block is to be made at the discretion of the pilot. However, once the pilot starts descent and verbally reports leaving an altitude in the block, the pilot may not return to that altitude without additional ATC clearance.

(compare to “N12345 Maintain 6,000’, where you have to stay at 6,000’)

What is Block Altitude?

A block of altitudes assigned by ATC to allow altitude deviations within it.

“Maintain block altitude 9 to 11 thousand.”

Approach Lighting Systems

ALSF: Approach Lighting System with Sequenced Flashing Lights
- ALSF-1, less common than ALSF-2 in the US.
- ALSF-2, >= 2,400 ft from the threshold.
MALSR: Medium Intensity Approach Light System with Runway Alignment Indicator Lights
SSALR: Simplified Short Approach Lighting System with Runway Alignment Indicator Lights
ODALs (Omni-Directional Approach Lights)

Decision bar: 1000 ft from runway threshold. All US approach lighting systems have it.

ALS ending with F (ALSF, MALSF, etc): with sequenced flashing lights; Sequenced Flashing White Lights ends at the decision bar, 1000 ft from threshold.
ALS ending with R (MALSR, SSALR, etc): with runway alignment indicator lights; 5 white flashing, starting from 1,600 ft from threshold.

Radar

Primary Radar

Pilot can request radar service from tower:

PAR: Precision approach radar, lateral and vertical guidance, has glide slope
ASR: approach surveillance radar, only lateral guidance, no glide slope
CIR: constant information radar

Primary vs Secondary Radar

Primary
- controllers only knows the position of the aircraft, extra workload for ATC to communicate.
- rely on reflection of the radar beam.
Secondary
- radar sends interrogations, transponder sends responses.
- request and responds on different frequencies (1030 MHz vs 1090 MHz)
- carries more data
- Mode A: 4 digit, each digit is 0-7
- Mode C: Mode A + altitude
- Mode S: Mode C + unique identifier + data
- ADS-B extends the message elements of Mode S, adding information about the aircraft and its position. This extended squitter is known as 1090ES.

What does RNAV1 mean?

RNAV 1 means the aircraft navigation system must be able to calculate its position to within a circle with a radius of 1 nautical miles. This accuracy must be achieved at least 95% of the flight time by the aircraft operating within the airspace, route, or procedure.

IFR regs

91.167 - 91.189

91.171 VOR checks for IFR
91.177 IFR min altitudes
91.185 Lost comm

95.15 US mountainous area

Fuel planning

Fuel planning need to include approach, missed approach.

Can you use a outdated database?

For flying IFR: yes, but need to verify the procedure hasn't been amended since the database expired.
For IFR checkride: no.

GPS Full scale deflection

GPS Modes:

ENR: En Route
TERM: Terminal Area, within 30 NM of the departure or destination airport
APP: Approach, within 2 NM of the Final Approach Fix (FAF)

Full scale deflection:

	ENR	TERM	APP
non-WAAS	5 nm	1 nm	0.3 nm
WAAS	2 nm	1 nm	0.3 nm

Contact approach vs Visual approach

visual: may be asigned, 1000 ft ceiling, 3 sm visibility
contact approach: must be requested by pilot, 1 sm visibility, clear of cloud

PTATEN: position report

Position
Type of flight plan
Altitude
TIME: ETA next fix
Next: fix after that