TGH Aviation offers aircraft component repair on the following Lockheed Models. Below is a list of the most commonly requested repairs and does not eliminate capabilities on other instruments used in this make of aircraft. If you need an instrument repaired that is not listed below, please call our Sales Department at 1 (800) 843-4976.
Veteran and Technician Brian Brown started with TGH Aviation in 2005. For the past fourteen years he has been the Repair Lead Tech working on Remote Vertical and Directional Gyros. Brian holds an Degree in Electronics and Served in the Airforce as an Airframe Powerplant Crew Chief.
TGH Aviation and its employees enjoy Brian’s sardonic humor and superior overhauls and repairs. His work carries quality and precision.
“Life isn’t about our routines; it’s about finding the hidden treasures of splendor in the tiny moments we have”
Corrie Vallance
When Brian is not at TGH, he enjoys spending time with his wonderfully large family. With seven children, a beautiful wife, many grandchildren and even a few great grandchildren, he stays busy and happy. His personal hobbies include reading and camping when he’s not taking care of his family.
You can be confident in TGH Aviation to be a trusted source for all your Flight Support Systems overhauls and repairs. We employ extraordinary people with great minds and infallible skills. Our dependability is the product of our exceptional team and the mission of TGH Aviation’s FAA Repair Shop.
Mario Monti moved to the United States from Italy in 2006 and landed in Placer County, California. As a prior jeweler and watch maker, Mario had great dexterity in working on small intricate motors and devices. He worked as an A & P Mechanic Apprentice at an on-field aircraft repair shop at the Auburn Municipal Airport in 2007. There he became affiliated with TGH Aviation and their instrument repair technicians.
Working on aircraft as a mechanic, Mario would often bring instruments to the TGH Repair Shop for repairs and overhauls. The experience in the avionics shop gave Mario a unique view on how flight system components function. When a position opened at TGH in 2009, they were pleased to welcome him aboard.
Discovering your destiny can happen in the most of imperceptible of events; staying humble can bring you home. – Corrie Vallance
Mario’s expertise brought him quickly up to speed on repairing and overhauling gyros. Ten years later, Mario is one of the main technicians in the repair facility for gyros. In addition to gyros, Mario applies his expertise to repairing and overhauling air-speeds, true air-speeds, pressure altimeters and encoding altimeters.
TGH Aviation is appreciative to have great employees like Mario, who came from the other side of the world, to offer their talent to the aviation industry and keep TGH as a trusted source of flight systems support worldwide for over 60 years.
Pitot Static System…Airspeed Calculation
A. Airspeed Calculation:
Airspeed is calculated as a function of the difference between Pitot Pressure and Static Pressure as follows:
Calculated or Indicated airspeed is indicated airspeed corrected for instrument errors, position error (due to incorrect pressure at the static port) and installation errors.
Calibrated airspeed values less than the speed of sound at standard sea level (661.4788 knots) are calculated as follows:
minus position and installation error correction.
Where
is the calibrated airspeed,
is the impact pressure (inches Hg) sensed by the pitot tube,
is 29.92126 inches Hg; static air pressure at standard sea level,
is 661.4788 knots:, speed of sound at standard sea level
Units other than knots and inches of mercury can be used, if used consistently.
This expression is based on the form of Bernoulli’s equation applicable to a perfect, incompressible gas. The values forand 
are consistent with the ISA i.e. the conditions under which airspeed indicators are calibrated.
Keep in mind that this is for your basic vanilla airspeed indicator and does not include calculations for TRUE Airspeed for which you must include the variables of True Temperature and True Altitude.
Stay tuned for upcoming Blogs
Pitot Static System ….Inside & Out
A. Pitot Pressure:
Pronounced: PEE-TOE, it is a French word
Pitot pressure is the measurement of the air forced into the Pitot Tube by the movement of the aircraft through the air. Pitot tubes are mounted on the aircraft facing forward so that air is forced into them. Most small aircraft have only one tube, larger aircraft have a redundant system and will have two tubes. The most common manufacturer of these tubes is Rosemont Corp. which is a division of BF Goodrich. Also on larger aircraft, those that fly at higher altitudes, the Pitot Tube is heated in order to prevent icing, smaller aircraft typically do not have this function.
The Pitot Tube is connected directly to the back of the airspeed indicator (the Pitot input) and if the aircraft is so equipped also to the Air Data Computer via a hose which is typically either plastic or rubber
B. Static Pressure:
Static pressure is the measurement of the ambient barometric pressure at the aircraft’s CURRENT location AND CURRENT Altitude.
The Static Port is located in a position on the aircraft that will not be affected by air flow as the aircraft moves through the air. This is typically on the side of the fuselage but can also be on the back side of the Pitot Tube or any other number of locations, it varies by the aircraft. Again smaller aircraft will typically have one Static Port, larger aircraft with redundant systems will have two.
The Static Port is connected directly to the following equipment, depending on aircraft configuration: The Airspeed Indicator (Static Input), the Altimeter, the Vertical Speed Indicator, the Altitude Encoder, the Air Data Computer. Again connection is typically made via a hose either rubber or plastic.
C. Airspeed Calculation:
Airspeed is calculated as a function of the difference between Pitot Pressure and Static Pressure as follows:
Calculated or Indicated airspeed is indicated airspeed corrected for instrument errors, position error (due to incorrect pressure at the static port) and installation errors.
Calibrated airspeed values less than the speed of sound at standard sea level (661.4788 knots) are calculated as follows:
minus position and installation error correction.
Stay tuned for upcoming Blogs
Overview of Capacitive Type Fuel Qty. Measuring Systems
The Capacitive Type Fuel Qty measuring system utilizes a variable capacitive element in order to vary a precise electrical AC voltage based on the quantity of fuel in the fuel tank. The varying electrical signal, in turn, is used to drive the pointer on a fuel quantity indicator in a manner which is proportional to the amount of fuel in the tank, thereby visibly indicating remaining fuel quantity to the pilot.
The typical components in this type of system include the following
1. Signal Conditioner or Control Monitor (If not included in the
indicator
2. Tank Unit (Fuel Qty Sender, Fuel Probe)
3. Indicator 
Stay tuned for upcoming Blogs
Typical Failures in Resistive Fuel Quantity Systems
Indicator
As previously stated the indicator in this type of system is quite simple, typically nothing more than a meter movement mounted within a case. A meter movement consists of a spool of wire mounted on a pivot and jewel housed within a frame. The frame is in fact a large powerful magnet.
As electrical current flows through the wire spool it interacts with the magnetic field of the frame causing the spool to rotate on its pivot and jewel.
Pivots
A pivot is nothing more than a miniature axle. A jewel is a finely ground glass cup within which the ends of the pivot are supported and allowed to rotate. Over time and with constant movement the ends of the pivot will begin to wear down similar to the point on a pencil. Eventually the pivot will become so worn that it can no longer rotate easily. It needs to be sharpened or replaced.
Jewels
As previously stated, a jewel is nothing more than a finely ground miniature glass cup. Glass is fragile; it breaks very easily when mishandled. The glass also becomes worn from the pivot constantly rotating within it. Eventually the glass will become rough and will need to be re-ground or replaced.
Magnets
The frame of the meter movement is a large magnet. A magnet is nothing more than a piece of steel within which all of the electrons, sub-atomic particles, have been aligned within a specific pattern. Eventually the electrons move and return to their original locations according to the laws of physics. With the loss of alignment the magnet loses its magnetic power.
However while the magnet is still operating properly it, like all magnets, attracts other ferrous metals. The pivot, manufactured with ferrous metal, is in close proximity to the magnet and it is wearing down from rotating within the jewel. As the pivot wears it throws off tiny particles of metal which are attracted to the magnet. Eventually enough of these particles will become lodged between the magnet and wire spool so as to inhibit free movement of the meter. The unit needs to be completely disassembled and thoroughly cleaned.
TANK UNITS
Resistive Elements
As previously described the resistive element is subject to wear from the constant movement of the wiper across its surface. Once it is overly worn or broken it must be replaced. There is no possibility of repair
Floats
The floats are very often nothing more than hollow metal balls. These sometimes spring leaks. The fuel must be drained and the float must be resealed.
Stay tuned for upcoming Blogs
Advantages & Disadvantages of Resistive Type Fuel Systems
Advantages of Resistive Type Fuel Measurement Systems
The primary advantage of this type of system is cost. The components are very simple and therefore very inexpensive to manufacture. A second advantage is reliability. Again these are very simple components involving very few piece parts to manufacture; the fewer parts that are involved then the less that can go wrong. The third and final advantage is that the system, while not optimal, does provide a reasonable amount of accuracy. When utilized on a small aircraft, carrying small quantities of fuel with a limited flight range the accuracy that is provided by this system is adequate.
Disadvantages of Resistive Type Fuel Quantity Systems
Inaccuracy due to Physics
The fuel, within the aircraft’s tanks, is subject to the laws of physics. Therefore it moves when the aircraft moves. It is affected by gravity and centrifugal force. When the aircraft banks for a turn the fuel slops to one side. When the aircraft climbs the fuel flows to the back of the tank. When the aircraft dives the fuel flows towards the front of the tank. The float is in a fixed position and can only respond to the up and down motion of the fuel. If all of the fuel has moved forward and away from the float then the float will fall down and indicate a lower amount of fuel then is currently available, conversely if the mass of fuel gathers in the area where the float is located then the float indicates a higher amount of fuel then what is actually available. Only when the aircraft is flying straight and level will the system provide an accurate report of fuel quantity. These types of inaccuracies are intolerable on a long range aircraft which is carrying thousands of pounds of fuel.
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Theory of Operation (Resistive FQM Systems)
For the purposes of discussing the operation of the Resistive Fuel Quantity Measurement System, in the paragraph below, the following assumptions are to be made:
1. The aircraft utilizes a 28 Volt DC Power Supply
2. The meter movement within the indicator is the most common type used, which is a 100mv, d’arsonval type. This means that it requires 100mv of electrical current to drive the pointer on the meter movement from zero deflection to full deflection.
When power (V+) is applied to one side the resistive element and ground is applied to the other end and the desired maximum electrical current is 100mv, then Ohm’s Law can be applied in order to determine the required value for the resistive element as follows:
R = E/I
Where R= Resistance, E= Voltage and I = Current.
Since the values of E and I are known, 28 Volts DC and 100mv respectively, then R is resolved as follows:
28/.1 = 280
Therefore the value of the resistive element to be used is equal to 280 Ohms at its minimum value, which would equate to a maximum current flow of 100mv.
A reasonable design, would dictate that the system would change 1mv for each 1% of fuel used. Using that model then 1mv (1% of the fuel remains) would be our zero point on our indicator. Once again Ohm’s Law dictates the value of our resistive element as follows:
28/.01 = 2800 Ohms
Therefore our resistive element must be variable from 280 ohms up to 2,800 Ohms.
The operation of the system is now very straight forward, when the fuel tank is empty the float is at its very lowest point and the wiper resistive element follows the float. Therefore the wiper is at the point of the resistor which is closest to ground and furthest from the source of power or 2800 Ohms. This would provide only 1mv of power to the meter movement and only 1% deflection of the pointer or our Zero (EMPTY) setting.
When the fuel tank is full the float and wiper both will be at their highest point, closest to the source of power or 280 Ohms. This would provide 100mv of power to our meter movement and 100% deflection of the pointer or our FULL setting.
As the voltage is constant and both electrical current and resistance are perfectly linear then our pointer travel will also be perfectly linear.
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Get to Know the Fuel Quantity Indicator
The indicator for a resistive fuel quantity system is typically a very simple instrument consisting mainly of a meter movement housed within a standard 3-1/8” case. On occasion the indicator may have some signal conditioning element within it, however that is quite rare and when it does occur even that will be a very simple voltage divider or a single stage amplifier.
The most common meter movement used in these indicators is of the d’arsonval type and which is typically 100 milli-volts full scale.
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