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Navy SBIR 24.1 - Topic N241-008
NAVAIR - Naval Air Systems Command
Pre-release 11/29/23   Opens to accept proposals 1/03/24   Now Closes 2/21/24 12:00pm ET    [ View Q&A ]

N241-008 TITLE: Oxygen Sensor for Fuel Tank Environment


OBJECTIVE: Develop an accurate oxygen sensor that can continuously operate in a fuel tank ullage environment with minimal maintenance required.

DESCRIPTION: On-Board Inert Gas Generator System (OBIGGS) is used to inert areas of the aircraft to reduce the risk of fire or explosions. Fuel tanks may utilize OBIGGS for both survivability and lightning protection, which require below 9% and 12% oxygen by volume, respectively. Feedback of the fuel tank ullage oxygen percentage would allow aircrew to select the proper oxygen concentration set-point for the situation, and receive feedback that the threshold has been reached. Due to requiring clean working environments, currently available oxygen sensors are not suitable for a fuel tank application. The desired oxygen sensor would be able survive in a fuel tank environment, accurately and continuously measure the oxygen concentration, maintain a small form factor, and require infrequent maintenance or repairs. The designed sensor would need to withstand the vibration loads and environmental requirements of a typical fighter aircraft flight profile, and meet the appropriate electrical criteria of a fuel tank environment. The oxygen sensor should be usable on any aircraft that is inerting fuel cells.

PHASE I: Identify the mechanism for the oxygen sensor that can withstand jet fuel and vapor. Develop an experimental bench top design to show the basic functionality and compatibility with the environment. Verify that the oxygen concentration readings are accurate in a lab setting. Develop a plan to address any technical hurdles with the design. The Phase I effort will include prototype plans to be developed under Phase II.

PHASE II: Produce an on-aircraft prototype of the oxygen sensor. Verify that size, power, and interface requirements are met. Perform appropriate environmental testing. Validate and demonstrate the sensor in a testing environment representative of a fuel tank.

PHASE III DUAL USE APPLICATIONS: Produce a final design that is ready for flight test. Provide documentation regarding sensor accuracy, operational limits, and failure analysis. Provide appropriate qualification documentation, including (a) environmental testing, (b) electrical testing/analysis, and (c) explosive atmosphere qualification.

Commercial aircraft fuel tanks could use oxygen sensor technology to ensure the tanks are inert. Additional applications may exist for storing commercial flammable liquids.


  1. Cavage, W. (2009). Measuring oxygen concentration in a fuel tank ullage. U.S. Air Force T&E Days 2009.
  2. Goswami, K., Sampathkumaran, U., Alam, M., Tseng, D., Majumdar, A. K., & Kazemi, A. A. (2006). Ormosil coating-based oxygen sensor for Aircraft Ullage. SPIE Proceedings.

KEYWORDS: Oxygen sensor; On-Board Inert Gas Generator System; OBIGGS; fuel tank; inert; oxygen; sensor


The Navy Topic above is an "unofficial" copy from the Navy Topics in the DoD 24.1 SBIR BAA. Please see the official DoD Topic website at for any updates.

The DoD issued its Navy 24.1 SBIR Topics pre-release on November 28, 2023 which opens to receive proposals on January 3, 2024, and now closes February 21, (12:00pm ET).

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Topic Q & A

1/23/24  Q. Could you let me kwow what is the target aircraft platform to install the oxygen sensor system
   A. The solution must be compatible with the full spectrum of Naval aircraft, from single seat jets to large transport to rotary wing.
1/11/24  Q. Does the sensor have to be inside of the fuel tank? Can we install the sensor outside of the tank and extract gas sample from the tank?
   A. The sensor must be in the tank, but major modifications to the fuel tank should be avoided. The design must withstand liquid fuel exposure due to maneuvering and inverted flight

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