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Gulfstream IV-SP (G-IV)

Picture of Gulfstream IV-SP (G-IV)

The Gulfstream IV-SP (G-IV) is a high altitude, high speed, twin turbofan jet aircraft acquired by AOC in 1996. The G-IV is currently configured for operational support of the National Hurricane Center synoptic surveillance mission and is expected to provide support for NOAA programs for many years to come. This mission is designed to collect, process and transmit vertical atmospheric soundings in the environment of the hurricane. The principle tool used for this task is the GPS dropwindsonde.

The dropsonde is released from the G-IV measuring and transmitting back to the aircraft the pressure, temperature, humidity, and GPS Doppler frequency shifts as it descends to earth. The Doppler shifts are used to compute the horizontal and vertical wind components. After analysis and processing of the dropsonde data the information is formatted into a TEMP-DROP message using the standard WMO format. The TEMP-DROP message is then transmitted to the National Centers for Environmental Prediction and the National Hurricane Center for inclusion into the global and hurricane model runs. The TEMP-DROP message is also provided to the hurricane forecaster providing real-time observations depicting the synoptic patterns surrounding the hurricane.

Picture of Gulfstream IV-SP (G-IV)

Gulfstream G-IV SP (Special Performance)

Gulfstream G-IV SP Transformation Article


Engines: Two Fuselage Mounted Rolls Royce Tay 611-8 twin spool turbofan jet engines
Crew: (Hurricane and Winter Storm Missions):
2 pilots
1 flight engineer/mechanic
1 flight meteorologist (flight director)
1 High Altitude Profiling System (HAPS) system operator (can be automated)
3 Engineering Technicians/Dropwindesonde (Sonde) system operators
Ceiling: 45,000 feet
Rate of Climb (approximate - fully loaded): 3000 fpm (first 25000 ft.)
1500 fpm (through 33000 ft.)
1000 fpm (to 41,000 ft. – max wt. ceiling)
Operational Airspeeds: 41,000 – 45,000 ft. True Airspeeds (Mach .77-.80, 440-460 kts.)
Electrical: Two engine driven alternators (36KVA, 115 volt, unregulated 3 phase)
One Auxiliary Power Unit (APU) (36KVA, 115 volt, 400Hz, 3 phase)
Two Converters (converts and regulates engine alternator power)
Each provides: 23KVA, 400Hz, 3 phase AC power
250 amps, 28 volts DC power
Scientific Power: SED has an Uninterruptable Power Source (UPS) for scientific gear
Max. Gross Weight: Ramp 75,000 pounds
Takeoff 74,600 pounds
Landing 66,000 pounds
Empty Weight: 43,700 pounds
(operational configuration)
Useful Load: 31,300 pounds
(operational configuration)
Fuel Load: 29,500 pounds
Type Fuel: Jet A, JP4, JP5, JP8
Standard Fuel Burn: (fully loaded) = 5000 pounds/hr for first hour and 3000 pounds/hr for every hour after that
Maximum Range: 3800 nm. (with a 1 hour fuel reserve)
Maximum Duration: 8 hrs. 45 minutes (with 1 hour fuel reserve)
External Dimensions: Radome to trailing edge of horizontal stabilizer = 87.58 ft.
Radome to aft end of fuselage = 78.83 ft.
Wing Span = 77.83 ft.
Horizontal Tail Span = 32 ft.
Vertical Tail Height = 24.4 ft
Internal Dimensions: Head Room = 6ft.
Bulkhead to Bulkhead = 8 ft.
Cabin Length (Cockpit to Baggage Comp.) = 33 ft.
Useable Volume: Usable Length = 33 ft.
Usable Width = 6 ft.
Usable Height = 4 ft.
Usable Volume = 792 cubic ft.
Additional Standard Equipment
Cockpit: 2 High Frequency (HF) Radios
2 VHF Radios
Honeywell SATCOM Phone
GPS and Inertial Reference Systems (IRS) for navigation
1 UHF Radio
Honeywell TCAS II System (with FAA Change 7)
EROS Quick Donning Oxygen System
Collins WXR-700C (C-band weather radar)
Cabin: Dropwindesonde Tube with 8-channel tracking capability
Satellite Communication System with voice/data transmission capability
Numerous Computer Systems

The specific equipment and systems onboard the G-IV for the hurricane surveillance mission are the:

  • Main Aircraft Data System

- Two Data System Modules for instrument interface and data collection
- Four Networked Sun Sparc5 Workstations
- Extensive atmospheric instrumentation

  • Airborne Vertical Atmospheric Profiling System

- Dropsonde Data System for drop execution, data collection and storage
- Dropsonde Launch Chute
- GPS dropwindsonde

  • Hurricane Analysis and Processing System

- Workstation accomplishes data analysis, processing, and message formatting

  • Internal/External communication system

- VHF, UHF, ADF, Flight Phone, SATCOM and Passenger Communication System

  • Rockwell Collins WXR-700C C-Band Weather Radar w/ 30-inch antenna

The G-IV aircraft is on standby or deployed 180 days for hurricane surveillance, another 30-60 days are required for instrumentation and calibration, and 30 days for maintenance and training while anticipating between 200 to 300 hours of flying every year.

NOAA G-IV Winter Storms Reconnaissance

February 28, 2012 - NOAA's Gulfstream IV-SP will operate out of Anchorage, Alaska during the next few weeks in support of the agency's Winter Storms Reconnaissance (WSR) program. The specialized aircraft will gather data as needed over the Pacific Ocean in an effort to enhance winter storm forecasts for the entire North American continent.

During the WSR missions, the aircraft will deploy special sensors over the ocean to collect information where the jet stream and moisture from the ocean interact and breed potentially powerful winter storms that impact North America several days later.

Data on wind speed and direction, pressure, temperature and humidity from the sensors will be monitored and quality checked by meteorologists aboard the aircraft. NFOAA then will use the information to predict the location and intensity of high winds, destructive surf conditions, severe weather and flooding rainfall caused by winter storms.

"These atmospheric observations, combined with satellite and other data, have proven to significantly enhance 4-7 day winter weather forecasts," said CAPT Barry Choy, NOAA, Chief Science Officer for the National Centers for Environmental Prediction (NCEP), part of NOAA's National Weather Service. "Improved forecasts mean longer warning lead times for the public, emergency managers, air carriers, utility companies and others to prepare for significant winter storms, protect lives and property and minimize economic impacts."

"Together, these flights will help forecasters paint a detailed three-dimensional picture of weather systems over Pacific regions where more accurate information is needed for computer weather forecast models," said Jack R. Parrish, Flight Director and Meteorologist with NOAA's Office of Marine and Aviation Operations (OMAO), Aircraft Operations Center (AOC)..

Prior to repositioning to Anchorage, the aircraft supported the WSR program out of its temporary base at U.S. Coast Guard Air Station Barbers Point in Honolulu HI. NOAA aircraft have supported the WSR program since 1998, when the program was established by NCEP.

Based at the NOAA Aircraft Operations Center, located at MacDill Air Force Base in Tampa, FL, the Gulfstream IV is part of the NOAA fleet of aircraft and ships operated, managed and maintained by the NOAA OMAO. The aircraft, which typically operates at an altitude of 40,000-45,000 feet, is also known for its role in Atlantic hurricane surveillance.

For more information on the Winter Storms project visit


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