Limitations

- James Albright (a former G450 driver)

Updated: 2016-04-26

Are these limits really limitations?

Lawyer's answer: Yes because the AFM says they are.

FAA's answer: See lawyer's answer.

Engineer's answer: Many of them are because the various computers helping you think they are and will remind you when you pass one by. (Just try extending the flaps at 251 knots, for example.) In most cases the numbers are conservative and your life will be considerably less stressful if you follow them.

My answer: In a few cases the numbers are designed to satisfy an FAA regulation — usually 14 CFR 25 — and not understanding that could hurt you. Maneuvering Speed (VA) and Minimum Control Speed Ground (VMCG), for example, are not what most pilots think and applying them blindly could break the airplane and all those aboard. (See VA and VMCG.) Some of the statements are just flat out wrong; you cannot dispatch with any blue CAS message, for example. You need to think each limitation through before making a decision.

If you are looking for a convenient sheet of limitations and other nice to know numbers, I recommend this gem: G450 Notes "short" version (Steven Foltz ).

Everything here is from the references shown below, with a few comments in an alternate color.

AFN, ADS-C, and CPDLC Operations

G450 Airplane Flight Manual §1-34-30 ¶6.] Airplanes having the latest approved version of the Honeywell PRIMUS EPIC system, comply with the interoperability requirements of RTCA D0-258A for AFN and ADS-C operations. Additionally, airplanes equipped with ASC 059 (or later approved Revisions) demonstrate compliance with RTCA DO-258A for CPDLC operations.

Interoperability requirements for ATS applications using ARINC 622 Data Communications (FANS 1/A Interoperability Standard) comply with RTCA DO-258A.
AFN, ADS-C, and CPDLC are also approved for oceanic and remote operation within the NAT and in areas outside of the NAT. The proper datalink capability must be noted on the filed ICAO flight plan: block 10 should include “J” and “/D”, and block 18 should include “DAT/SV”.
NOTE: This constitutes engineering approval only. Operational approval must be obtained from the local authority (FSDO) prior to using ADS-C and / or CPDLC capability. Requirements and operational guidance are found in AC 120-70x.

If you have enhanced navigation and an LOA or OpsSpec, you are good to go.

See CPDLC.

Airspeed

[G450 Airplane Flight Manual §1-03-40]

(VFE/MFE) Maximum Flaps Extended 10°: 250 KCAS/0.60 MT

(VFE/MFE) Maximum Flaps Extended 20°: 220 KCAS/0.60 MT

(VFE/MFE) Maximum Flaps Extended 39°: 180 KCAS/0.60 MT

(VLE/MLE) Maximum Landing Gear Extended: 250 KCAS/0.70 MT

(VLO/MLO) Maximum Landing Gear Operation: 225 KCAS/0.70 MT

(VLO-alternate) Maximum Landing Gear Alternate Operation: 175 KCAS

Maximum Tire: 195.5 knots

(VMCA) Minimum Control Speed Air: 106 KCAS

(VMCL) Minimum Control Speed Landing: 99 KCAS

(VMCG) Minimum Control Speed Ground: 109 KCAS

This number reflects a specific set of certification conditions of Gulfstream's choosing and is actually too low for the aircraft at sea level. Your V1 will always be higher so make sure you keep the nose wheel steering in mind until then.

See VMCG for the real story behind VMCG.

(VA) Maneuvering Speed: 206 KCAS

This number applies only to specific weights, configurations, and altitudes. The real numbers for most of your time down low for takeoff and landing are considerably lower.

See VA for an explanation of why.

(VMO) Maximum Operating Speed 0 to 28,000': 340 KCAS

(MMO) Maximum Operating Speed 28,000' to 34,000': 0.85 MT

(MMO) Maximum Operating Speed 34,000' to 43,500': 0.88 MT

(MMO) Maximum Operating Speed 43,500' to 45,000': 0.874 MT

Maximum Mach Trim/Elevator Trim Inoperative: 0.75 MT

Turbulence Penetration (below 10,000'): 240 KCAS

Turbulence Penetration (above 10,000'): 270 KCAS/0.75 MT (whichever less)

Maximum speed with emergency stabilizer trim armed, autopilot engaged and a jammed elevator: 270 KCAS/0.75 MT

Yaw Damper Inoperative Speed

Above 20,000 ft the minimum speed is 210 Kts.
Below 20,000 ft the minimum speed is in accordance with the schedule below until ready to configure for approach and landing.

Fuel Quantity (1000 lb) 8 10 12 14 16 18 20 22 24 26 28 30

Minimum Airspeed (KCAS). 96 107 117 126 135 143 151 158 165 172 178 184

Altitude

[G450 Airplane Flight Manual §1-03-30]

Maximum operating: 45,000'

Maximum operating with yaw damper and Mach trim compensator inoperative: 41,000'

Maximum operating with flaps 10 or 20: 25,000'

Maximum operating with flaps 39: 20,000'

Maximum operating with landing gear extended: 20,000'

APU

Figure: APU Operating Envelope, from G450 Airplane Flight Manual §1-49-40, figure 1-8.

Operation

[G450 Airplane Flight Manual §1-49-10]

The APU can be operated on the ground, during takeoff, in flight and during landing. In flight it is an optional source of electrical power via the APU GEN instead of one or both engine-driven generators.
MAXIMUM PERMISSIBLE EGT
- Start: 973°C
- Maximum Running: 746°C
- Maximum Continuous: 665°C
MAXIMUM ROTOR SPEED All conditions: 107%

Starting Limits

[G450 Airplane Flight Manual §1-49-20]

Continuous operation of the APU starter, when powered by airplane batteries is limited to a maximum of three (3) consecutive start attempts. A one (1) hour cool down period must be observed before the next full starter cycle is commenced.
APU start attempts when powered by an external DC cart are limited to a maximum of three (3) attempts. A fifteen (15) minute cool down is required between start attempts to protect airplane wiring. A one (1) hour cool down period must be observed before the next full starter cycle is commenced.
CAUTION: ALLOW FIFTEEN (15) MINUTES BEFORE ATTEMPTING ANOTHER APU START USING EXTERNAL DC POWER. THIS ALLOWS THE ELECTRICAL FEEDER CABLE FROM THE EXTERNAL POWER RECEPTACLE TO THE APU STARTER TO COOL.
NOTE: Successful consecutive starts are limited to 6 at 10 minute intervals per start.

Electrical Load

[G450 Airplane Flight Manual §1-49-30] The APU generator can deliver 100% electrical power (40 kVA) on the ground or in flight from sea level to 37,000 ft (maximum altitudes for APU operations). APU generator loading will be limited to 85% between 30,000 ft and 37,000 ft at speeds greater than Mach .85.

APU Start Envelope: Guaranteed to 37,000'

More about it: G450 APU.

CAS Messages

[G450 Airplane Flight Manual §1-45-50] Amber CAS messages are DO NOT DISPATCH messages. Blue CAS maintenance messages allow dispatch as the systems that generate these messages are fault tolerant. Dispatch with an active amber or blue message shall be with reference to the MEL.

This simply isn't true, there are at least seven blue CAS messages you cannot dispatch with and the list seems to be growing.

See G450 Warnings, Cautions & Notes.

Charts

[G450 Airplane Flight Manual §1-134-110]

On airplanes equipped with ASC 059B (or later approved revision), the PlaneView Charts function is FAA certified as part of the airplane type design as a Class 3 Electronic Flight Bag (EFB) with Type C software applications.
For airplanes not equipped with ASC 059B (or later approved revision), the PlaneView Charts Function is FAA certified as part of the airplane type design. It is functionally equivalent to a Class 3 Electronic Flight Bag (EFB) with type C software applications. The PlaneView Charts Function may fail if a DMU, LAN or data transfer card fails, so either paper charts or a Class 1 or Class 2 EFB that is accepted by the FAA and contains Airport Diagrams, Departure, Arrival and Approach Charts must be readily available to the flight crew.
The charts effectivity dates shall be checked prior to the first flight of the day. If the chart dates review reveals the chart information has expired or if the amber “May Contain Outdated Data” statement is present on the Charts master page, the crew shall check the NOTAMS for the airports prior to dispatch. Alternately, the crew may elect to update the database prior to dispatch or use current paper charts for the trip.
The crew shall report all noted discrepancies concerning charts to Jeppesen as soon as possible after the discrepancy has been noted. Jeppesen can be contacted via e-mail at www.jeppesen.com. Select “Feedback” under Jeppesen Quick Links.
The airplane symbol on the Chart Display must not be used for navigation of the aircraft. However, it can assist situational awareness during all phases of flight including taxi.

If you have enhanced navigation, the electronic charts in PlaneView are all you need. Otherwise, you will need either a backup tablet or iPad with an authorized chart application, such as Jeppesen's FlightDeck, or paper charts to back up your departure, destination, alternate, and equal time point airports.

For more about this, refer to AC 91-78 and AC 120-76C.

Electrical System

Standby Electrical Power System

[G450 Airplane Flight Manual §1-24-10]

When the Standby Electrical Power System (HMG) system is in operation, speed brakes may be used provided operation is slow (approximately three (3) seconds for full range movement).
When operating on Standby Electrical Power System (HMG), consult the list of operative items in Section 4-04-10: Dual Generator Failure.
Do not operate the Standby Electrical Power System (HMG) system when normal AC power is available, except as provided for in Section 3-04-30: L (or R) ESS DC Bus Failure.

See G450 HMG Limitation Explained.

Integrated Drive Generator

[G450 Airplane Flight Manual §1-24-20] The Integrated Drive Generator (IDG) electrical load is limited to 45% (18 kVA) when ambient temperature is greater than 110°F / 43.5°C in order to maintain steady state fuel temperatures below 95°C.

The G450 IDG has an independent integral oil system that is cooled using a dedicated fuel cooled oil cooler which uses LP fuel to cool its oil. If the IDG oil gets too hot it could impact engine operation.

See G450 Electrical System for an in depth explanation.

Enhanced Vision System (EVS)

G450 Airplane Flight Manual §1-34-90]

The HUD section of the G450 Operating Manual (Chapter 2B, PlaneView System, Basic Issue or later approved revision) must be immediately available to the flight crew whenever use of the EVS system is contemplated.
At 100 feet HAT, visual cues must be seen without the aid of EVS to continue descent to landing.
EVS may be used only by qualified pilots who have been trained in accordance with requirements listed in the FAA G450 Flight Standardization Board (FSB).
Flight director or autopilot with vertical guidance is required for all IMC EVS approaches.
EVS as installed meets the requirements of EFVS (Enhanced Flight Vision System) as defined in FAR 91.175.
Vertical Guidance Requirements for IMC EVS Approaches: Flight Director or autopilot with vertical guidance, either ILS or FMS vertical path, is required for all IMC EVS approaches. With respect to an FMS vertical path, only approaches with a published Decision Altitude (DA) and those approaches that overlay a precision approach with the same vertical path angle provide an assured obstacle-free vertical path.

The rules on how low you can go are laid out pretty well in 14 CFR 91.175 but you should know how they impact your instrument approach capabilities.

More about this: Enhanced Flight Vision Systems.

EGPWS

G450 Airplane Flight Manual §1-34-60]

EGPWS. Pilots are authorized to deviate from their ATC clearance when complying with an EGPWS warning.

EGPWS. Terrain display shall be selected off when within 15 nm of landing at an airport when: the airport doesn't have a published IAP; the longest runway is less than 3,500'; the airport is not in the database.

Flight Controls and Automation

Automatic Ground Spoilers

[G450 Airplane Flight Manual §1-27-30]

Takeoff is permitted with the automatic ground spoilers inoperative provided the anti-skid is operative, 20 flaps are used and the cowl and wing anti-ice systems are not used. Dispatch with reference to MEL.
If a touch and go landing is to be performed, GND SPLR must be OFF and manual spoiler landing distances must be taken into account.

Autopilot

[G450 Airplane Flight Manual §1-22-30]

Minimum engage height is 200 ft.
Minimum disengage height is 60 ft from an ILS / MLS and LPV approach.
Minimum disengage height is 50 ft below MDA / DA from an LNAV / VNAV approach.
Maximum demonstrated altitude loss for coupled go-around is 60 ft.

Autothrottle

[G450 Airplane Flight Manual §1-22-70] Use of the autothrottle during single engine approaches is prohibited.

Coupled Go-Around

[G450 Airplane Flight Manual §1-22-20]

Coupled Go-Around : Single-engine autopilot coupled go-around is not approved.

Emergency Stabilizer Trim

[G450 Airplane Flight Manual §1-22-60] Maximum speed with the emergency stabilizer armed with the autopilot engaged and a jammed elevator is 270 KCAS / M 0.75.

Mach Trim

[G450 Airplane Flight Manual §1-22-10]

Use of Mach Trim Function: Mach trim must be ON during all flight operations except as provided for in Section 3-02-40: Mach Trim Failure.
If Mach Trim is inoperative: MMO is reduced to 0.75 MT.

Speed Brakes

[G450 Airplane Flight Manual §1-27-20] Speed brakes are not approved for extension with flaps at 39° (DOWN) or with landing gear extended in flight.

Stall Warning / Stall Barrier System

[G450 Airplane Flight Manual §1-27-10]

There are two stall warning / stall barrier systems installed in the airplane. Dispatch with one stall warning / stall barrier system inoperative is allowed with reference to the MEL.
Operative stall barrier systems must be ON during all flight operations unless required to be selected OFF for procedural reasons.

FMS

[G450 Airplane Flight Manual §1-34-30]

Software: Verify that the navigation computer software version is NZ7.X or later approved version. Verify that the database is current. If the database is out of date, flight may be continued providing the latitude / longitude of each waypoint is verified by the crew. A current database is required in order to fly any approach procedure using the FMS.
High Latitude Navigation: FMS Navigation above 89° North or South Latitude is approved.
Approaches:
1. Approved procedures:
  - RNAV (GPS) or RNAV (GNSS) or RNP
  - RNAV (RNP) or RNP AR APPH
  - GPS or GNSS
  - VOR / DME RNAV
  - VOR*
  - VOR / DME*
  - TACAN*
  - NDB*
2. *Approaches above, suffixed with an asterisk, may be flown with FMS guidance provided the appropriate civil aviation authority has approved such operations. See that country’s Aeronautical Information Publication, or AIP, to confirm approval. In the US, AC 90-108 advises that RNAV systems cannot be used as a substitute for the navaid lateral guidance during the final approach segment.
3. Limitations and exceptions:
  1. The final segment of the approach must be flown with the FMS in the Approach Mode. DR or DEGRADE annunciators cancel the Approach Mode.
  2. For airplanes having ASC 059B (or later approved revision), RNAV (GPS) or RNAV (GNSS) approaches can be executed to LPV minima. When loading an approach with LPV minima into the FMS, either graphically or using the MCDU, the FMS will default to the LPV criteria. Removing the LPV criteria from the FMS in order to perform the approach using LNAV or LNAV / VNAV minima can be done only using the MCDU. With the LPV mode captured, it is recommended that transition to LNAV minima or a go-around be performed if the LPV Unavailable caution CAS message displays.
  3. NOTE: EGPWS Mode 6 must be operable and the associated audio call outs not inhibited, when performing RNAV (GPS) approaches to LPV minima.
  4. Prior to conducting RNAV (RNP) approaches with Authorization Required (AR), appropriate operational approval (i.e., Operations Specifications (OpsSpecss), Letter of Authorization (LOA), or Management Specifications (Mspecs)) must be obtained. Requirements and operational guidance are found in AC 90-101, and in the Gulfstream RNP AR Operations Manual, GAC-OIS-02 or GAC-OIS-07 (basic issue or later approved revision).
  5. For airplanes having ASC 059B or (later approved revision) with SBAS receivers), SBAS-enabled GPS navigators are in compliance with TSO-145c/146c.

Fuel System

Fuel Load Balancing

[G450 Airplane Flight Manual §1-03-80]

For maximum unbalanced fuel, see [the figure]. Before the unbalance exceeds that shown, proceed with fuel balancing.
Fuel balancing may be accomplished by using the crossflow valve or intertank valve.
When balancing fuel through use of the crossflow valve, ensure tank temperature is above 0°C and boosted fuel pressure is always available to the engines. If fuel temperature is 0°C or below, use the intertank valve to balance fuel.
CAUTION: THE ENGINE WILL ONLY RUN ON SUCTION FUEL FEED AT OR BELOW 20,000 FT. ABOVE 20,000 FT, THE ENGINE WILL RUN ERRATICALLY AND FLAME OUT IF THE CROSSFLOW IS NOT OPEN WITH AT LEAST ONE BOOST PUMP ON.
Balancing fuel by using the intertank valve requires the airplane to be placed in a sideslip condition. Adjusting the rudder trim in the direction of the “heavy” tank will create a wing down condition and allow fuel to flow toward the “light” tank.

See: G450 Fuel Unbalanced for balancing procedures.

Usable Fuel Capacities

[G450 Airplane Flight Manual §1-28-10]

Per tank: 2,185 gallons (14,750 lbs)
Total: 4,370 gallons (29,500 lbs)
NOTE: It may be possible to upload fuel in excess of 29,500 lbs. This is permitted as long as the maximum ramp weight and / or the maximum takeoff weight is not exceeded, and the loaded airplane center of gravity is within limits.

Boost Pumps

G450 Airplane Flight Manual §1-28-20] All boost pumps must be on during flight except for fuel balancing.

Fuel Tank Temperature

G450 Airplane Flight Manual §1-28-30] Maximum: Fuel temperatures of +54°C or greater will cause a Red Fuel Tank Temperature message to be displayed on the Crew Advisory System (CAS).

G450 Airplane Flight Manual §1-28-30] Minimum: For airplanes S/N 4001- 4244 without ASC 908B, 909 or 910 (or later approved revisions):

Fuel temperatures of -35°C to -36°C will cause an Amber Fuel Tank Temperature message to be displayed on CAS.
Fuel temperatures colder than or equal to -37°C will cause a Red Fuel Tank Temperature message to be displayed on CAS.

G450 Airplane Flight Manual §1-28-30] Minimum: For airplanes S/N 4001-4244 with ASC 908B, 909 or 910 (or later approved revisions) and 4245 and Sub:

Fuel temperatures colder than or equal to -39°C will cause an Amber Fuel Tank Temperature message to be displayed on CAS.
Fuel temperatures colder than or equal to -40°C will cause a Red Fuel Tank Temperature message to be displayed on CAS.

If your fuel temperature is cold enough to generate a CAS message, you should monitor the temperature all the way to landing. Fuel tends to adhere to its surroundings best at -12°C and the increasing fuel flow demands once the aircraft is configured for landing has been known to clog fuel filters.

See: British Airways 38.

More about: G450 Fuel System.

Hydraulics System

[G450 Airplane Flight Manual §1-29-10]

Maximum reservoir quantities (pressurized) as indicated on EICAS:

Left: 2.75 gallons
Right: 0.70 gallons

Accumulator pre-charge: 1200 psi @ 70°F ± 25 psi per 10°F Δ.

More about: G450 Hydraulics Systems.

Ice & Rain

G450 Airplane Flight Manual §1-30-10]

Icing conditions exist when the SAT on the ground and for takeoff, or SAT in-flight is +10°C (50°F) or below, and visible moisture in any form is present (such as clouds, fog with visibility of one mile or less, rain, snow, sleet and ice crystals).
Icing conditions also exist when the SAT on the ground and for takeoff is +10°C (50°F) or below when operating on ramps, taxiways or runways where surface snow, ice, standing water, or slush may be ingested by the engines or freeze on engines, nacelles, or engine sensor probes.
Takeoff is prohibited with frost, ice, snow, or slush adhering to the wings, control surfaces, engine inlets, or other critical surfaces.
A visual and tactile (hand on surface) check of the wing leading edge and the wing upper surface must be performed to ensure the wing is free from frost, ice, snow, or slush when the outside air temperature is less than 42°F (6°C), or if it cannot be ascertained that the wing fuel temperature is above 32°F (0°C); and
- There is visible moisture (rain, drizzle, sleet, snow, fog, etc.) present; or
- Water is present on the wing; or
- The difference between the dew point and the outside air temperature is 5°F (3°C) or less; or
- The atmospheric conditions have been conducive to frost formation.

Wing Anti-Icing

G450 Airplane Flight Manual §1-30-20] Operation of wing anti-icing is required if icing conditions are imminent, or immediately upon detection of ice formation on wings, winglets, or windshield edges.

Cowl Anti-Icing

Figure: Temperature Range for Cowl Anti-icing, from G450 Airplane Flight Manual §1-30-30.

Use of cowl anti-icing is required for taxi and takeoff when Static Air Temperature (SAT) is +10°C (50°F) or below and visible moisture, precipitation, or wet runway are present. When taxiing or holding on the ground at low power in temperatures less than +1°C, engine operation of 85% LP for two (2) seconds is recommended just prior to takeoff. At intervals of not more than sixty (60) minutes, under these temperature and moisture conditions, accelerate the engines to 85% LP, pause for one (1) minute, then resume operations.
Use of cowl anti-icing system is required in flight as indicated in [the figure], Temperature Range for Cowl Anti-Icing, when visible moisture or precipitation is present or when signs of icing are observed. Ice accretion may be observed on wings or windshield edges.
Increase in engine vibration levels may develop in icing. The fan should normally shed the ice and vibration will return to normal. To assist in shedding ice, if high vibration occurs and operational circumstances permit, one engine at a time may be quickly retarded to idle, held there for five (5) seconds and then accelerated to 85% LP for two (2) seconds, the power lever may then be returned to its original position.
Automatic anti-ice is inhibited above 35,000 ft. If anti-ice protection above 35,000 ft is required, it must be manually selected.

More about: G450 Ice & Rain Protection.

IRS

[G450 Airplane Flight Manual §1-34-10]

There is no provision for IRS “Down Mode Align”.

NOTE: Honeywell HG2100AB and HG2100BB Series IRS equipment installed in the Gulfstream G450 has been certified for alignment to 78° Latitudes. For alignment between 70° and 78° Latitude, fifteen (15) minute alignment time is required. For flight above 73° N and 60° S Latitude, EFIS heading information must be switched from magnetic (MAG) to TRUE due to loss of valid MAG heading from the IRS.

There are no restrictions for in air automatic realignment – Align in Motion (AIM). However, the AIM alignment time may be less than 10 minutes or more than 20 minutes, if any of the following conditions are present either alone or in combination:

No change in heading during alignment
No changes in acceleration during alignment
An east to west flight trajectory such that the IRUs sensed rotational rates in inertial space is nearly equal to zero.

NOTE: Airplane maneuvers involving changes in heading reduces alignment time. Alignment time increases with latitude, i.e., minimum time is at the equator and maximum is at the pole.

Landing Gear

Anti-Skid System

G450 Airplane Flight Manual §1-32-10] Takeoff is permitted with anti-skid inoperative, provided the runway is dry, ground spoilers are operative, 20° flaps are used, and the cowl and wing anti-icing systems are not used. Dispatch shall be with reference to the MEL.

Landing Lights

G450 Airplane Flight Manual §1-32-20] Ground operation of landing lights is limited to five (5) minutes.

Operations Permitted

[G450 Airplane Flight Manual §1-03-10]

Transport Category-Land
Instrument And Night Flying
Category 1 Approach Operations
Flight Into Known Icing
Extended Over Water Flight
The aircraft is definitely okay for extended operations within 180 minutes of the nearest suitable airport and can go even further. Under 14 CFR 91 you could technically venture further away without any formal approval but you will need Operations Specifications to allow you to do this under 14 CFR 135.
See Extended Operations (ETOPS) for more on this.
Polar Navigation:
1. TRUE heading must be selected prior to N73° and S60° Latitude.
2. Operation must be conducted in accordance with the guidance and limitations expressed in Section 01-34-30, Flight Management System (FMS).
"Polar Navigation" has morphed into "High Latitude Operations" in the last few years. Either way, they present a few challenges you need to consider. For 14 CFR 135 you will need Operations Specification approval. For 14 CFR 91 you should seriously consider taking the same precautions.
See High Latitude Operations for more on this.
Radius to a Fix (RF) legs: Aircraft meets the requirements of AC 90-105, Appendix 5 to fly Radius to a fix (RF) legs during any segment of a procedure, without limitation.
The "without limitation" statement needs to be tempered by the fact the only place you will find these RF legs is on an RNP AR, formerly called RNP SAAAR, approach and you do need an LOA or Operations Specification approval for that.
See AC 90-101, RNP Procedures with SAAAR, for more about that.
VNAV system is approved for approach operations
1. Aircraft meets the accuracy requirements of VFR/IFR en route, terminal, and approach operations in accordance with the criteria of AC 20-138x.
2. VNAV QFE operations not authorized.
Category II Operations
1. ASC 020 required.
2. Operation must be authorized by civil aviation authorities via Letter of Authorization or OpsSpecs.
AFN, ADS-C, and CPDLC Data Link Operations
1. Aircraft complies with the interoperability requirements of DO- 258A as expressed in the AFM, Section 01-34-30, Flight Management System (FMS).
2. Operation must be authorized by civil aviation authorities via Letter of Authorization or OpsSpecs.
3. Operation must be conducted in accordance with the guidance and limitations expressed in Section 01-34-30, Flight Management System (FMS).
4. Other requirements and operational guidance are found in AC 120-70X and ICAO’s GOLD (Global Data Link Document) Manual.
There is more about these earlier under AFN, ADS-C, and CPDLC Operations. If you have enhanced navigation and an LOA or OpsSpec, you are good to go.
See CPDLC.
North Atlantic Track Minimum Navigation Performance Specifications (NAT MNPS) Airspace Operations
1. Aircraft may be flown on routes requiring two Long Range Navigation (LRN) systems provided that two FMS’s, two GPS position sensors, or two Inertial Reference System (IRS) position sensors or one GPS and one IRS sensor are operational.
2. Aircraft may be flown on routes requiring one LRN system provided that one FMS, one GPS position sensor, or one IRS position sensor are operational.
3. Operation must be authorized by civil aviation authorities via Letter of Authorization or OpsSpecs.
Reduced Vertical Separation Minimums (RVSM) Operations: Operation must be authorized by civil aviation authorities via Letter of Authorization or OpsSpecs.
RNAV and RNP Operations
NOTES:
1. RNP (general): Aircraft complies with RNP RNAV as defined in RTCA/DO-236B and DO-283, with the limitations and exceptions defined in Section 01-34-30, Flight Management Systems (FMS).
2. RNP 10: Aircraft operation for an unlimited time period when GPS or radio position sensors are being used. If GPS or radio position sensors are not available, compliance is limited to 5.0 hours of IRS-only navigation.
3. Authorization Required: Operation must be authorized by civil aviation authorities via Letter of Authorization or OpsSpecs.
4. Section 01-34-30: Operation must be conducted in accordance with the guidance and limitations expressed in Section 01-34-30, Flight Management System (FMS).
5. RNAV-SBAS: ASC 059B (or later approved revision) required to fly an RNAV (GPS) or an RNAV (GNSS) approach to LPV minima.
6. RNP AR:
  1. Without ASC 059B (or later approved revision), minima less than RNP 0.3 not authorized, and missed approach segments less than RNP 0.3 not authorized.
  2. With ASC 059B (or later approved revision), minima less than RNP 0.1 not authorized, minima less than RNP 0.3 require the use of the autopilot, and missed approach segments less than RNP 0.1 not authorized.
The FMS is certified for LNAV (lateral navigation) and VNAV (vertical navigation) in accordance with the criteria in the following Advisory Circulars: AC 25-15, AC 20-129, AC 20-130x, AC 20-138, AC 90-45x, AC 90-96x, AC 90-100x, AC 90-101x and AC 90-105. AC 20-138x supersedes the following Advisory Circulars but the approval of the FMS is still valid for the operations and conditions as stated in Section 1 — Limitations of the AFM: AC 20-129, AC 20-130A, AC 20-130B and AC 90-45A.
CVR Datalink Recording for airplanes S/N 4001 thru 4229 having ASC 072 and airplanes 4230 and Sub.
For airplanes equipped with ASC 908 (or later approved revision), AFN and ADS-C for oceanic and remote operations.
NOTE: Appropriate operational approval must be obtained prior to using ADS-C and/or CPDLC- FANS 1/A capability. Requirements and operational guidance are found in AC 120-70x.
Controller Pilot Data Link Communications (CPDLC) For Oceanic and Remote Operations.
- For airplanes having ASC 059B or (later approved revisions), CPDLC-FANS 1/A for oceanic and remote operations.
- Note: The aircraft ATC data link system has been demonstrated to comply with the applicable safety and performance requirements of EUROCAE ED-120, the interoperability requirements of ED-110B and with AMC 20-11. This AFM entry does not, by itself, constitute an operational approval where such approval is required.
- For airplanes S/N 4001 thru 4229 with ASC 071 and S/N 4230 and sub, CPDLC-FANS 1/A for oceanic and remote operations.
For more about this, see CPDLC.
For airplanes equipped with ASC 059B (or later approved revision) the installed SBAS receiver is authorized for use with WAAS, EGNOS, GAGAN and MSAS.
ADS-B, operative for airplanes with ASC 079 or ASC 084. The installed ADS-B Out system has been shown to meet the equipment requirements of 14 CFR 91.227.

Oxygen & Pressurization Systems

Cabin Pressure Control

[G450 Airplane Flight Manual §1-21-10]

Maximum cabin pressure differential: 9.94 psi
Maximum cabin pressure differential for taxi, takeoff, landing: 0.3 psi

Oxygen Departure Pressures

What about oxygen for the passengers? The only chart giving this is in the Extended Operations (ETOPS) section of G450-OMS-02, Table III.

You can read more about that here: G450 Oxygen.

Oxygen Masks

[G450 Airplane Flight Manual §1-35-20]

Above FL250 oxygen masks must in the quick-doning position which allows donning within 5 seconds.
Crew/Passenger oxygen masks are not approved above 40,000' cabin altitude.
Wait a minute! The G550 is certified for flight to 51,000' and the G450 to 45,000' - so why are the masks only good to 40,000'? Aircraft certified under 14 CFR 25.841 must be designed so that occupants will not be exposed to a cabin pressure altitude that exceeds the following after decompression from any failure condition not shown to be extremely improbable — Gulfstream seems to believe it is extremely improbably that you will not be able to get the airplane below 40,000' cabin altitude.
PASSENGER MASKS ARE INTENDED FOR USE DURING AN EMERGENCY DESCENT TO AN ALTITUDE NOT REQUIRING SUPPLEMENTAL OXYGEN.
WARNING: PASSENGER MASKS WILL NOT PROVIDE SUFFICIENT OXYGEN FOR PROLONGED OPERATION ABOVE 34,000 FT CABIN ALTITUDE. PROLONGED OPERATION ABOVE 25,000 FT CABIN ALTITUDE WITH PASSENGERS ON BOARD IS NOT RECOMMENDED.

More about this: G450 Oxygen.

People & Places

People

[G450 Airplane Flight Manual §1-01-10] Minimum flight crew is a pilot and copilot.

[G450 Airplane Flight Manual §1-01-20] Total number of occupants shall not exceed 22. The number of passengers shall not exceed 19 as determined by emergency exit requirements, nor shall exceed the number for which seating accommodations approved for takeoff and landing are provided.

Runway and Wind

[G450 Airplane Flight Manual §1-02-10]

A runway is considered wet when it is well soaked (there is sufficient moisture on the runway surface to cause it to appear reflective) but without significant areas of standing water. The runway is considered contaminated when more than 25% of the runway surface area (whether in isolated areas or not), within the required length and width being used, is covered by surface water more than 0.125 inch (3mm) deep, or by slush or loose snow equivalent to more than 0.125 inch (3mm) of water.
Maximum slopes for takeoff and landing are plus/minus 2%.
Maximum tailwind component for takeoff and landing is 10 knots.

High Elevation Airport Operations

[G450 Airplane Flight Manual §1-02-20]

Maximum approved airport pressure altitude for takeoff or landing is 14,500 ft field elevation.
For airplane Serial Numbers (SN) 4001 through 4220 with ASC 068 incorporated and SN 4221 and subs, the maximum approved altitude for takeoff or landing is 15,000 feet field elevation.

Position Sensors

G450 Airplane Flight Manual §1-34-30 ¶7.] The selected sensor for the FMS position is chosen by comparing the EPU values of all available sensors that have not been deselected by the pilot, and choosing the sensor with the lowest value. Sensor accuracy is the produced Figure of Merit (FOM) for GPS and Hybrid IRU, and the computed EPU for IRS drift and radio position. Once a sensor is selected, that sensor remains selected unless the EPU of another sensor is at least 5% lower than the EPU of the selected sensor. For an instrument approach selected from the NAV database, the selected sensor functions in one of two ways: When the database record indicates that the chosen approach has a required sensor (e.g., GPS required), then that sensor is locked as the selected sensor at three miles from the FAF and remains the selected sensor throughout the approach. When the database record does not indicate that the chosen approach has a required sensor, the sensor with the best accuracy when the aircraft is three miles from the FAF is locked as the selected sensor for the remainder of the approach.

Powerplant

Engine Operation

The 60 kts. limitation on the thrust reversers is most likely to prevent damage to the flaps caused by reversed airflow at slower speeds, but there are other theories.

See: G450 Powerplant Exhaust, for more.

Ground Start

[G450 Airplane Flight Manual §1-71-20]

The engine is capable of starting in crosswinds of up to 25 knots and tailwinds of up to 25 knots.
CAUTION: IN TAILWINDS GREATER THAN 10 KNOTS THE DIRECTION OF ROTATION OF LP MAY BE INITIALLY REVERSED. IF SO THE FUEL CONTROL SWITCH SHOULD NOT BE SET TO RUN UNTIL THE LP INDICATION CONFIRMS POSITIVE ROTATION.
To ensure positive rotation of LP, the following actions are required following selection of ENG START Switch to ON:
- If LP rotation increases immediately, continue with starting operations
- If LP speed decreases, passing through zero, then increases, continue with starting operations
- If LP speed decreases, then stabilizes, abort start

Takeoff Power

[G450 Airplane Flight Manual §1-71-30] Minimum acceptable power for takeoff is shown in Section 5: Normal Takeoff Planning. Takeoff in the ALTERNATE (LP) control mode is prohibited.

Static Ground Run

[G450 Airplane Flight Manual §1-71-40]

While static on the ground, stabilized engine operation between 60% and 72% LP is prohibited. Any acceleration through this band must not exceed 10 seconds. The FADEC will not keep the engine out of the 60% to 72% LP range unless the parking brake is set.

Thrust Reversers

[G450 Airplane Flight Manual §1-78-10]

Cancellation of reverse thrust should be initiated so as to be at the reverse idle position by 60 KCAS.
Use of idle reverse thrust is available for taxi purposes without time limit.
The thrust reversers shall be deployed and stowed at least once every 100 hours.
If in an emergency, reverse thrust is used to bring the airplane to a halt, record and report such an operation for maintenance action.
Use of thrust reverser(s) for power back is not approved.
Dispatch with inoperative thrust reverser(s) on a wet runway requires that the available runway length be reduced by 600 feet or the accelerate-stop distance be increased by 600 feet.

Oil Inlet Temperature

[G450 Airplane Flight Manual §1-79-10]

Oil Inlet Temperature

Min for starting: -40°C
Min before increasing power: -30°C
Max: +105°C

Oil Pressure

[G450 Airplane Flight Manual §1-79-20]

Minimum at idle: 17 psi
Min for takeoff: 30 psi
Min to complete flight: 25 psi (at MCT), 20 psi (at 86% HP), 16 psi (at 76% HP)

Starter Duty

[G450 Airplane Flight Manual §1-80-10]

Starter Duty: 3 minutes on, 15 seconds off, 3 times, then 15 minutes

More about this: G450 Powerplan t.

Radar

[G450 Airplane Flight Manual §1-34-20]

Do not operate radar during refueling nor when within 300 ft of refueling operations.

Do not operate radar within 49 ft of ground personnel (with 24" antenna installed).

More about this: G450 Radar.

RNP Operations

G450 Airplane Flight Manual §1-34-30 ¶5.] Aircraft complies with RNP RNAV Operations as defined in RTCA / DO-236B and DO-283, have been demonstrated with the following limitations and exceptions:

NOTE: The FMS RNP demonstration does not constitute an operational approval.

RNP flight operations are subject to GPS satellite availability and / or navaid coverage for the selected route. Crews should deselect (NOTAM) ground navaid(s) that are not to be used for navigation.
Navigation Infrastructure: The FMS assumes the availability of a navigation infrastructure consistent with the assumptions provided in DO-236B / DO-283 Appendix C.
The FMS assumes all waypoint and facility location data is in WGS-84 reference datum whereby the waypoints and facilities accuracy is maintained in accordance with DO-201 specifications.
More about this: WGS-84.
Scope of DO-236B Compliance: The FMS does not provide the Time of Arrival Control (TOAC), fixed radius transitions, or RNP holding functions described in DO-236B.
Alarm Limits: The RNP implementation for the FMS is consistent with the industry guidance provided in DO-236B and DO-283. Implementation of RNP requirements resulted in certain differences from the TSO C129a requirements. The FMS provides a containment integrity limit as defined in DO-236B. The RNP containment limit is defined as two times the RNP value, and the default RNP values are defined as 0.3 for Approach, 1.0 for Terminal Area, 2.0 for En Route, and 10.0 for Oceanic / Remote.
For the FMS database defined GPS approach procedure, the FMS limits the alarm limit to 0.3 for consistency with TSOC129a. However, for other approach procedures, the DO-236B alarm limit applies. For airplanes having ASC 059B (or later approved revision), the FMS alarm limit for RNP AR approaches less than 0.3 RNP is 1.5 (one and one-half) times the RNP value.
For airplanes having ASC 059B (or later approved revision), and operators having RNP AR approval, the RNP values for RNAV (RNP) approaches are retrieved from the navigation database. When loading a RNAV (RNP) approach with multiple RNP value minima into the FMS, either graphically or using the MCD, the FMS will default to the lowest RNP value minima. Changing the RNP value minima can only be done using the MCDU.
The FMS does not provide the capability to retrieve a RNAV RNP value from the navigation database, except as described in item (G) above. Default RNP values are defined by flight phase, as shown above. Operation in airspace with defined RNP values, different from the default values, requires operator entry of the appropriate value.
Runway Initialization: If GPS position is not available at take-off and RNP operations are required, the FMS position must be updated prior to take-off for improved navigation accuracy. The FMS position shall only be updated to the runway coordinates when the airplane is located on the runway threshold.
Don't do this unless you do not have GPS — two negatives there, okay, try this: only do this if you don't have GPS.
Time to Alarm: The FMS provides a time to alarm based on phase of flight, consistent with the default RNP values and expected RNP usage defined in DO-283.
Database Integrity: The RNP RNAV airworthiness approval has accounted for database accuracy or compatibility. Refer to the Operators Manual for the procedures for database accuracy / compatibility compliance.
The operators manual has the exact same statement but no such procedures.
Containment Integrity Exposure Period: The containment integrity requirement defined in DO-236B is that the probability of total system error exceeding the cross-track containment limit without annunciation be less than 10-5 per flight hour. This integrity requirement is divided equally between faulted and fault-free performance. The probability of faulted performance has been shown to be less than 5x10-6 per flight hour. For fault-free performance, the instantaneous probability of exceeding the integrity limit has been shown to be less than 5x10-6, however the exposure period has not been considered in the fault-free case.
Along-track Accuracy: Containment alerting is based on cross-track navigation performance; however navigation accuracy is required in both the cross-track and along-track dimensions. Because of the unique NAVAID geometries involved in the DME / DME and VOR / DME updating modes, navigation performance is optimized in the cross-track dimension. As a result, along-track accuracy has not been demonstrated to meet the RNP requirement for these modes. For DME / DME, the worst-case along-track uncertainty is 0.47 NM on a 95% basis wherever signals can be received. For VOR / DME, the worst-case along-track position uncertainty will occur when the VOR is abeam the airplane at the maximum permissible distance based on the figure of merit (service volume) of the facility.
Minimum RNP: The minimum demonstrated RNP capabilities are defined as follows, based on demonstrated navigation capability and assumed Flight Technical Error (FTE).
Assumed Guidance ModeMinimum RNPAssumedGPSRadioFTELNAV with Autopilot≤0.300.300.125LNAV with Flight Director0.300.320.25

RVSM

RVSM Dispatch Capability

G450 Airplane Flight Manual §1-34-110]

In order to satisfy the performance standards set forth in FAA AC 91-85, the following equipment and instruments must be installed and operative prior to dispatch into RVSM airspace:

ATAEquipmentNo. InstalledNo. Required for RVSM22-7Flight Guidance Computers2134-8ATC Transponder and Automatic Altitude Reporting Systems21*34-23Altitude Alerting System1134-33Air Data Computers / Systems (see chart)32

* One transponder may be inoperative provided that both the altitude reporting systems are operative on the remaining transponder.

NOTE: Refer to the MEL for other basic dispatch capability.

RVSM Envelope

Synthetic Vision-Primary Flight Display (SV-PFD)

G450 Airplane Flight Manual §1-34-170]

Aircraft without ASC 059 must either have backup paper charts or a Class 1 or Class 2 EFB readily available to the flight crew.

SVS must be deselected in non-WGS-84 countries.

TCAS

G450 Airplane Flight Manual §1-34-50]

TCAS. All RA/TA aural messages inhibited at a radio altitude less than 500' +/- 100' climbing and descending.

TCAS Pilot's are authorized to deviate from ATC to the extent necessary to comply with an RA.

TCAS. Compliance with RA required unless unsafe to do so.

TCAS. When single engine, select TA only.

Temperature

[G450 Airplane Flight Manual §1-03-20] Minimum and maximum temperatures approved for operation are shown in [the figure]

NOTE: Inadvertent encounters with atmospheric conditions where the SAT is colder than -70C can occur. In order to not exceed structure and equipment design temperature limits, the following minimum Mach schedule shall be maintained until the airplane can return to operations within the envelope.

SAT -°C. -70 -72 -74 -76 -78 -80

Min - M 0.67. 0.71. 0.76. 0.80. 0.84. 0.87

So can you fly for extended periods below -70°C as long as you keep your Mach number up? It is unclear. I once spent a few hours at -75°C and M 0.80 only to have the flaps freeze in the up position and ended up flying a no flap into Madrid, Spain. Anecdotal? Sure. You decide. I now read the note to say you need to return to a warmer temperature.

VGP Mode

G450 Airplane Flight Manual §1-34-180]

VGP requires the approach be flown from a "Vectors" transition, or the entire approach be flown.

Weight, Center of Gravity, and Flight Load Acceleration

Center of Gravity

[G450 Airplane Flight Manual §1-03-70] The allowable Center Of Gravity (CG) range is a function of gross weight as shown in [the figure], Zero Fuel Gross Weight Center Of Gravity Envelope chart. Zero fuel gross weight CG must be within the allowable zero fuel gross weight CG envelope. The fueled airplane CG will then be within limits for all fuel loads.

Flight Load Acceleration

[G450 Airplane Flight Manual §1-03-50]

Flaps 0°: -1 to 2.5 G
Flaps 10° or 20°: 0 to 2.0 G
Flaps 39° up to max landing weight: 0 to 2.0 G
Flaps 39° above max landing weight: 0 to 1.5 G

Weight

[G450 Airplane Flight Manual §1-03-60]

Max Zero Fuel Weight: 49,000 lbs. (48,000 lbs with ASC 008)

Max Landing Weight: 66,000 lbs. (Without ASC 007C)

Max Takeoff Weight: 73,900 lbs. (74,600 lbs with ASC 016)

Max Ramp Weight: 74,300 lbs. (75,000 lbs with ASC 016)

[G450 Aircraft Service Change 007C, pg. 1] This service change provides instructions to install a placard in the cockpit to reduce the Maximum Landing Gross Weight to 58,500 pounds for Category C instrument approach operations. With this ASC incorporated, along with With this ASC incorporated, along with the placard and Airplane Flight Manual Supplement (AFMS), the aircraft must be operated at the reduced maximum landing weight limitation as defined by the AFMS. If operations at standard (Pre ASC) maximum landing weight limitation are desired, the placard shall be removed from the aircraft by maintenance action, including log book entry, and the AFMS shall be removed from the flight manual.

If you have the sheets of paper known as ASC 007C on your aircraft, your maximum landing weight is 58,500 lbs. At least that's how our FSDO interprets it.

See G450 Approach Category for more about this.

WGS-84 (Non-WGS-84 Airspace / Countries Partially Compliant with WGS-84)

G450 Airplane Flight Manual §1-34-30 ¶4.] When operating in non-WGS-84 airspace or in countries where the airspace is partially compliant with WGS-84, the FMS with GPS position updating meets the required navigation accuracy and may be used for SIDS, STARS and en route navigation. When flying ILS, VOR or ADF approaches and missed approach procedures in these two situations, the GPS updating does not need to be inhibited or deselected provided the appropriate raw data is used throughout the approach and missed approach as the primary navigation reference. For countries that are partially WGS-84 compliant, when RNAV (GNSS) approaches are offered, these approaches may be flown using the FMS with GPS position updating provided the approach chart is annotated with “PANS OPS”.

More about this: WGS-84.

References:

Gulfstream G450 Airplane Flight Manual, Revision 36, December 5, 2013

Gulfstream G450 Operating Manual Supplement, G450-OMS-02, Extended Operations (ETOPS) Guide, Revision 2, April 2, 2009