TDG Aerospace

UFI®: Fuel Pump Protection

UFI® Application: Aircraft Fuel Boost Pump Protection

The first application of UFI® technology is the comprehensive protection of aircraft fuel boost pump systems from:

  • Electrical fault conditions
  • Extended dry-operation
  • Un-commanded operation

Due to its low cost, high reliability and ease of installation, the UFI® is quickly becoming the solution of choice for operators seeking compliance with center tank SFAR 88 mandates. FAA-approved STCs are currently available for fuel pump protection on a variety of aircraft, including B757, B767 and B737NG.


The UFI® is currently the only device of its kind certified to 14 CFR 25.981,

Amendment 102.



757 UFI® STC ST01950LA

  • Approved Means of Compliance to FAA AD 2008-11-07 (see par. (p) of AD)


737NG UFI® STC ST02076LA

  • Approved as an Alternate Means of Compliance to FAA AD 2002-24-51, par. (b) (see page 3 of STC)
  • Approved as an Alternate Means of Compliance to FAA AD 2001-08-24, par. (a) (see page 3 of STC)


767 UFI® STC ST02285LA

  • Approved as an Alternate Means of Compliance to FAA AD 2001-15-08, par. (b) & (c), (see page 3 of STC)
  • Approved as an Alternate Means of Compliance to FAA AD 2009-16-06, par. (f) & (h), (see page 3 of STC)
  • Approved as an Alternate Means of Compliance to FAA AD 2001-15-08, par. (i) for deactivated supplemental (high flow) jettison pumps


In cooperation with our airline partners, TDG is currently developing and certifying UFI® installation kits for the remaining Boeing fleets - providing our customers with an elegant alternative to expensive and cumbersome aircraft modification solutions.

Those operators that do not have the maintenance resources to rapidly implement UFI® on their aircraft are encouraged to contact American Airlines Maintenance Services ( American Airlines engineering and maintenance personnel have been extensively involved in the certification of UFI® technology and are uniquely positioned to ensure that installation efforts are efficient and fully compliant with the STC.

Electrical Fault Protection

The UFI® reliably detects line-to-ground and line-to-line faults in the boost pump wire harness or pump motor windings. It will also detect intermittent opens in the wire harness, connectors or pump motor.

Extended Pump Dry-Operation

Making use of the unique current / voltage signature generated when a synchronous motor is no longer doing work, the UFI® can detect when the fuel boost pump inlet is uncovered and the pump is no longer moving fuel. Based upon regulatory guidance, the UFI® will allow this condition to persist uninterrupted for fifteen (15) seconds before removing power from the boost pump.

Un-commanded Pump Operation

In the fuel boost pump application, the UFI® installation implements redundant pump control relays and a patented startup and power-on self-test (POST) sequence to ensure that the flight crew maintains control of power supplied to the fuel boost pumps at all times.  The UFI® POST sequence verifies internal system integrity and also positive control of both redundant relays in the open and closed states prior to applying power to the pump. This functionality is unique to the UFI® and not only enhances overall system safety, but also greatly reduces scheduled maintenance requirements.

Downloadable Database

The UFI® utilizes a non-volatile database to record pump operational parameters and fault information for use by maintenance personnel in troubleshooting fault conditions or accomplishing preventative maintenance. Information such as maximum startup currents, historical average current / voltage on each phase and specific fault data could be invaluable to maintenance or reliability personnel. The UFI® interfaces to a laptop computer and provides the relevant information in a .csv file that is readily imported into spreadsheet tools such as MS Excel.  On more than one occasion, data recorded by the UFI® has even helped maintenance personnel troubleshoot unrelated fuel system discrepancies with the FQIS and low pressure indication systems.

Document Access