14 years ago today, on January 23rd, 2007, the Lockheed Martin CATBird took its first flight. The rather strange-looking Boeing 737-300 was modified to be an avionics testbed for the F-35 Lightning II. Let's take a look at this interesting project and what it was built to do.

From German passenger aircraft to American fighter jet testbed

While this special aircraft would take flight in its modified form in 2007, its story would originate all the way back to November 1986. It was at this point in time that the aircraft was delivered to German carrier Lufthansa to begin commercial passenger service.

Registered D-ABXH and given the name 'Cuxhaven,' the aircraft operated with Lufthansa for 15 straight years. This was followed by one year of serving with Indonesian Airlines from March 2002 to May 2003 under the registration PK-IAA. Its final months of commercial service were spent with Lufthansa before crossing the Atlantic to join Lockheed Martin in September 2003 under registration N35LX.

Testing the most advanced avionics package in the world

The Lockheed Martin CATBird (Cooperative Avionics Test Bed) was designed to validate the F-35 Lightning II's avionics suite. For those unaware, the F-35 Lightning II was developed through the Joint Strike Fighter (JSF) program to be a highly advanced multi-role fighter jet.

"The Lightning II's avionics package will be the most advanced, comprehensive, and powerful of any fighter in the world," Lockheed Martin noted in a 2007 statement. The planemaker added that the CATBird's role was to integrate and validate the performance of all F-35 sensor systems before they were to be flown on the first Lightning II aircraft.

"The rigorous testing performed on board the CATBird will ensure that mature functionality is delivered to the F-35 Lightning II." - Eric Branyan, Lockheed Martin VP of F-35 Mission Systems

Catbird
A shot of the test stations inside CATbird. Photo: Lockheed Martin

Huge differences from a passenger 737

As you might expect, significant modifications were made to the CATbird to turn it into a testbed for fighter jet avionics. These major physical modifications to the aircraft were made in Mojave by BAE Systems, with support from Lockheed Martin.

The testbed included stations in the main cabin, and instrumentation to monitor and measure the in-flight performance of various sensors installed. Electrical and cooling support systems were also installed, as was "a high-fidelity F-35 cockpit" to enable pilots "to operate and monitor the fighter's integrated sensor suite in an airborne environment."

Changes to the aircraft included:

  • Modifying the nose of the 737 to replicate the F-35,
  • The addition of a 13-foot canard to emulate the F-35 wing
  • The addition of external structure on top and bottom to hold F-35 avionics equipment
  • The installation of about 1,500 wiring harnesses to connect and link the various mission system sensors.

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Mission accomplished

Lockheed Martin developed the F-35 Lightning II with principal industrial partners Northrop Grumman and BAE Systems. The CATbird was a key part of the jet's development.

Funded primarily by the United States, the F35's development would also garner investment from other NATO countries and US allies, including the UK, Australia, Canada, Italy, Norway, and more. Costs in developing the aircraft soared into the hundreds of billions of dollars, with the timeline of the project facing years of delays. This was largely due to the intended roles and capabilities for the aircraft, which would be quite lofty.

A goal of developing a single fighter jet that could serve multiple roles and missions for various branches of the military would prove difficult. Air Force Magazine noted in 2016 that planners from the US Air Force, Navy, and Marine Corps had anticipated three variants of the joint strike fighter having 70% commonality. However, a planner for the program noted that the results (in order to meet each branch's requirements) came out much differently: "it's 20-25% commonality … almost like three separate production lines," Joint Strike Fighter program manager Lt. Gen. Christopher Bogdan said at the time.

Did you know about the ex-Boeing 737, Lockheed Martin CATbird? Let us know by leaving a comment.