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AN/APQ-166 Radar

AN/APQ-166 Radar

Manufacturer: (Originally U.S. defense contractor)
Category: Radar Systems
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Detection Range Not publicly disclosed
Frequency Band Unspecified (legacy strategic radar)
Antenna Type / Technology Mechanically scanned parabolic reflector
Target Tracking Capacity Limited, legacy tracking

Full Specifications

1. General Information

Name / Designation	AN/APQ-166
Manufacturer	(Originally U.S. defense contractor)
Country of Origin	United States
Type / Role	Strategic Radar
Operational Domain	Airborne, bomber (B‑52)
Status	Being phased out / legacy

2. Technical Specifications

Frequency Band	Not publicly disclosed (legacy radar)
Antenna Type	Mechanically scanned parabolic reflector
Antenna Aperture / Size	Not publicly disclosed
Power Output	Not publicly disclosed
Detection Range	Not publicly disclosed
Tracking Range	Not publicly disclosed
Target Tracking Capacity	Limited, legacy
Elevation Coverage	Not publicly disclosed
Azimuth Coverage	360° (mechanical scan)
Beam Steering	No (mechanical)
Pulse Repetition Frequency (PRF)	Not publicly disclosed
Resolution	Coarse compared to modern AESA
Update Rate	Slower, due to mechanical scanning
Clutter Rejection / ECCM	Minimal / obsolete

3. Functional Capabilities

Primary Functions	Navigation, terrain following, weather avoidance, bombing support
Target Types	Ground, terrain, weather phenomena
Integration / Networking	Integrated into B-52 avionics
IFF Capability	Legacy IFF systems (if present in B-52)
Data Link / Networking	Basic legacy data output (not AESA / modern networked link)
Weather & Terrain Resistance	Supports terrain and weather modes
Mobility / Mounting	Fixed in B‑52 nose radome

4. Physical & Operational Characteristics

Dimensions	Not publicly disclosed
Weight	Not publicly disclosed
Power Requirement	Legacy aircraft power
Cooling System	Air‑cooled / legacy
Operating Temperature Range	Standard military aviation
Deployment Platform	B‑52G / B‑52H Stratofortress
Crew Requirement	Operated via radar navigator / bombardier station

5. Software & Processing

Signal Processor Type	Legacy analog / early digital
Processing Speed	Much slower than modern AESA
AI / Automation Features	None
Data Output / Interface	Legacy radar display / avionics
Software Upgradeability	Very limited / not modernized

6. Operational History

Year Introduced	During the Cold War (1960s–70s)
Users / Operators	U.S. Air Force (B-52G/H)
Notable Deployments	Strategic bomber missions, long-range bombing
Successor / Predecessor	Successor: AN/APQ-188 AESA radar

7. Export / Compliance Data

Export Availability	Very limited / not publicly exported
ITAR / MTCR Status	Likely ITAR-controlled system
Cost Estimate	Not publicly disclosed

Our Rating

The overall rating is based on review by our experts

3.8

Range & Endurance 4 / 10
Stealth Capability 2 / 10
Technology 4 / 10
Maintenance Efficiency 5 / 10

PROS

Proven legacy system with decades of operational history
Integration with B‑52’s navigation, terrain, and bombing systems
Reliable in simpler mission sets
Well-understood maintenance procedures (by legacy crews)
Enables strategic bomber missions even on aged platforms

CONS

Parts are obsolete and hard to source
Mechanically scanned, limiting scan speed and resolution
Vulnerable to high maintenance downtime
Provides no modern AESA features (e.g., multi-target tracking, ECM resistance)
Reaches end-of-life support as B‑52 modernization moves to AESA systems

AN/APQ-166 Strategic Radar System

The AN/APQ-166 is the legacy airborne radar system installed on the B‑52 Stratofortress, one of America’s most enduring and mission‑critical strategic bombers. Designed during the Cold War, the APQ-166 served as the primary navigation, targeting, terrain-avoidance, and weather radar for decades — but now faces mounting obsolescence and reliability challenges.

Origin & Manufacturer

The AN/APQ-166 is part of the U.S. military’s “AN/APQ” designation family, listed as a strategic radar under JETDS nomenclature. It was originally developed in the mid-20th century and has been installed on B-52G and B-52H variants. The system is becoming increasingly difficult to maintain due to diminishing manufacturing sources and obsolete technology.

Purpose & Capabilities

The APQ-166’s core mission is strategic radar, providing terrain following, weather detection, and navigation for the B-52 over long-range missions. It supports both nuclear and conventional strike operations, enabling the Stratofortress to fly low, avoid terrain, and deliver payloads accurately.

Despite its long service, the system has serious limitations: many components date back to the 1960s and 1970s, such as the antenna reflector and feed casting, which remain original in some aircraft. Maintenance remains a constant headache, with failure rates increasing and parts becoming scarce.

Operational Challenges & Modernization

Under the U.S. Air Force’s B-52 Radar Modernization Program (RMP), the APQ-166 is being phased out in favor of the next-generation AN/APQ-188 AESA radar, developed by Raytheon (RTX) and based on F/A-18 and F-15 radar technology. The RMP replaces up to 14 line‑replaceable units (LRUs) per aircraft, including antenna, control panels, and radome, to restore long-duration reliability.

Technical Limitations

As a mechanically scanned legacy radar, the APQ-166 lacks advanced capabilities found in modern AESA systems: limited target resolution, slower scan rates, and reduced resistance to electronic countermeasures. Furthermore, dwindling supplier sources make its repair increasingly costly and risky.

FAQs

What aircraft uses the AN/APQ-166?

The radar is used on the B‑52G and B‑52H Stratofortress bombers.

Why is the U.S. Air Force replacing the AN/APQ-166?

The system suffers from aging hardware, limited parts availability, and increasing failure rates, making it unsustainable on long-duration missions.

What will replace the AN/APQ-166?

Raytheon’s AN/APQ-188 AESA radar, derived from F/A-18 and F-15 radar families, is being integrated under the B‑52 Radar Modernization Program.

Is the AN/APQ-166 exportable to allied nations?

There is no public information suggesting active export; it is a legacy U.S. radar system likely restricted under ITAR.

When did the AN/APQ-166 first enter service?

The APQ‑166 dates back to the Cold War era (1960s–1970s), making it one of the oldest radar systems currently in U.S. strategic bomber use.

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