What are the Specifications & Features of EDM 800 in Aircraft?

EDM 800The EDM 800 puts the fun back into flying because as a pilot, you don’t have to spend bulk of the flight time staring at a bunch of dials to ensure the aircraft engine is functioning normally; the EDM 800 does this task for you.

Using the latest microprocessor technology, the EDM 800 monitor up to twenty-four critical parameters of the aircraft engine and it does this four times a second.

Superior to the EDM 700, the EDM 800 includes fuel flow monitoring and a host of other features. As before, leaning is accomplished automatically using the Lean Find procedure. With the EDM 800 you have more engine diagnostic information available. In fact, the EDM 800 records, all 29 functions, every 6 Seconds. Its memory can hold up to 25 hours of data. The pilot can also opt to record data every minute in which case the memory will hold 550 hours of data. This data can be downloaded via the optional USB port.

The all new EDM 800 provides you with a full-time in-flight readout of aircraft engine horsepower – this helps the pilot achieve maximum engine performance. The EDM 800 converts your RPM manifold pressure outside air temperature and fuel flow into horsepower. To achieve this a small one-time calibration is required. The details are in the instruction manual and easy to follow.

Features of EDM 800 include:

– 24 Programmable alarm limits
– No hassle, front panel programming
– Small 2 ¼” installation foot-print
– Lean Find finds the first and last cylinder to peak with true peak detect.
– Displays both leaned temperature below peak and peak.
– Designed for use with a single 6 cylinder engine with fuel flow.
– Battery voltage with alarm
– EGTs to stable 1°F resolution
– DIF low to high EGT with alarm
– User selectable index rate
– Shock cooling monitored on every cylinder
– Non-volatile long term memory
– Records and stores data up to 30 hours
– Post-flight data retrieval
– FAA Approved as primary temperature instruments for CHT Probes, OIL, TIT, RPM, MAP, Fuel Flow
– Fuel quantity in pounds, gallons, kilograms or litres
– Low fuel quantity alarm
– Low fuel time alarm
– GPS interface-Instantaneous fuel flow rate
– Total amount of fuel consumed
– Total fuel remaining
– Time to empty at the current fuel flow rate

All of JPI’s EDM’s are TSO’d for Quality

For more information please visit: https://www.jpinstruments.com/shop/ed-800/


Features & Applications of Outside Air Temperature (OAT) Probe

OAT probeData from the OAT probe on aircraft can be used in several calculation such as flight planning, aircraft take-off performance, cruise performance, density altitude and so forth.

In modern day aircraft, external air temp obtained via the Outside Air Temperature (OAT) probe, for the basic input for air data computers. There are two things to be kept in mind; one, the Static Air Temperature, or SAT, i.e. the temperature of the undisturbed air through which the aircraft will fly and second, the air temperature as the aircraft flies through it. This latter temperature is always a bit higher than the former (dur to kinetic energy is converted to heat at the sensor).

Although the OAT probe in aircraft is important, most pilots / owners of aircraft tend to ignore it. OAT data is used for recognizing potential icing conditions and in determining such essential parameters as density altitude and true airspeed. Ideally, the OAT probe should be part of the Advanced Flight Systems EFIS package or at least part of any other glass cockpit package, or as a stand-alone gauge in a traditional cockpit.


To begin with, the OAT probe should be mounted externally of the aircraft – not in the cabin air scoops, not inside the fuselage and definitely not inside the cowling. You won’t get accurate Outside Air Temperature reading this way.

Generally speaking, the probe should be placed away from any sources of heat, and out of direct sun light. A location under the wing, sufficiently outboard to avoid exhaust heat, or on the bottom of the fuselage would be ideal.

For single engine installation, avoid mounting the OAT Probe on the side of the aircraft. Additionally, for the OAT to function accurately, a sun shield must also be installed.

Most OAT have two wires (moulded or unmoulded). One wire would be red – this is the power supply wire. The other wire carries the Temperature Sensor Aircraft data from the Outside Air Temperature (OAT) probe to the instrument receiving the information.

Remember that the temperature indicated by the OAT probe is the Ram Air Temperature (RAT) so called because the oncoming air as it is brought to rest and compresses at the front of the probe. For those technically included, you can arrive at the actual OAT by using the formulae TAT = SAT + (K × TAS² / 7592)

Where: TAT is the output from the probe. SAT is figure to be derived (in Celsius). K is the recovery factor of the probe (usually 0.8 to 0.9). TAS is True Airspeed (TAS) is in knots.

For more information purchase, please visit: https://www.jpinstruments.com/shop/oat-probe/

Installation of Engine Data Management 700 (EDM 700) System in Aircraft

Engine Data Management 700Having acquired the Aircraft Engine Data Management System 700 (EDM 700), it goes without saying, that this awesome piece of equipment needs to be carefully handled and installed.

While the JPI warranty at the back of the instruction manual clearly states that JPI will replace defective parts under warranty, it does not cover mishandling or defective installation.

Care to be taken while installing the JPI EDM 700:

1. The JPI Aircraft Engine Data Management System 700 is packaged along with 4 screws. While fixing these screws, care should be taken to ensure that the four mounting screws should not penetrate the instrument more than 0.12 inches.

2. The person installing the EDM 700 must be a FAA certified aircraft mechanic. While we are sure there are many Do-it-Yourself pilots and aircraft owners out there, the installation of the Aircraft Engine Data Management System 700 is best handled by an officially (FAA) certified person who knows what he (or she) is doing.

3. Before installing the EDM 700, the mechanic should check if there are any STC (FAA approvals) available for the aircraft.

4. While installing the EDM 700, care should be taken to crimp ring terminals with a good crimping tool (e.g. AMP part 45518) crimp tool or equivalent.

a. Ideal procedure is to fold back the wire double before crimping terminals – about 1/4″ 1 1/2″
b. Fold back wire double before crimping terminals 2 1/4″ of Thermocouple wire harness red and yellow

5. Installation of the EDM 700 will require some parts that are likely to be unique to your make and model of aircraft hence these are not part of the EDM 700 kit. The instruction manual will guide the mechanic as to the parts that will be required. All necessary parts should be acquired prior to the installation.

6. While acquiring parts, care should be taken to not buy/use any aluminium fittings with the FXT-201 or FXT-231 Fuel Flow Transducer.

7. Before installation note the K-factor engraved on the side of the fuel flow transducer.

8. Carefully select and mark the location of all the holes before drilling ensuring that nothing will interfere with the wires, probes, clamps and screws.

9. It is a good idea to provide service loops at the instrument – this will come in handy during future maintenance work.

10. Provide service loops for thermocouple wire too as it will allow you to swap probes on adjacent cylinders for future troubleshooting purposes.

11. Ensure all wires are kept away from high temperature components such as exhaust stacks.

12. Thermocouple wire should not be spliced using copper wire. Only K-type thermocouple wire.

13. Solder using zinc chloride flux such as Nokorode brand – rosin flux alone won’t work.

14. When connecting wires to probes, ensure correct polarity.

15. This instrument must be grounded at the engine, not at the avionics ground.

More information at: https://www.jpinstruments.com/shop/edm-700/

What are the key features of CRB Probe?

CRB ProbeThe Carburettor Temperature Probe (CRB) is used to detect temperature drop in the carburettor.

For successful ignition to occur, the air-fuel mixture has to be perfect and this can only happen at the right temperature. Now when fuel and air is mixed, the temperature inside the carb will drop dramatically and this is compounded due to external cold air and cold temperatures. Next thing you know – the carburettor is frozen solid – and this is not something you want to happen when flying; not by a long shot.

So, the carburettor is kept warm and steady at its ideal temperature through a rather ingenious way by installing an anti-icing system and using air heated by the aircraft engine. This marvel of modern aviation engineering keeps the aircraft carburettor as warm as a kitten sleeping next to a fire. Not too hot – just right temperature keeps the kitten and carburettor happy.

But an aircraft being what it is i.e. an amalgamation of thousand different parts; moving and non-moving, anything can happen so the pilot needs to know the moment the carburettor is not too comfy because it’s impact on the engine and aircraft can be far reaching and catastrophic. Enter the CRB probe.

The Carburettor Temperature Probe (CRB) is connected either to an independent analog or digital gauge (the type of probe used will depend on type of display you have in the cockpit). The moment the pilot detects a drop in the carburettor temperature, he can start the pre-heater and it will heat the air flowing over the carb thereby preventing the carburettor from freezing over.

To ensure accurate temperature reading, the Carburettor Temperature Probe (a sensor), is mounted directly on the carburettor wall. This, along with other indicators (e.g. drop in RPM Sensor, rough sound etc.) serve as a warning to the pilot(s) that all is not well.

Modern CRB probe like those manufactured by J.P. Instruments, are meant to be immune to factors such as oil, humidity and gasoline. They are also engineered to withstand wide temperature fluctuation.

Each CRB has a sensing coil within it. This coil is fully coated in an epoxy resin which in turn sits within a metal tube thick enough to withstand repeated backfires, but thin enough to be highly sensitivity to temperature change. This fine balance is perfectly achieved by only a few CRB manufacturers and J.P. Instruments is one of them.

The CRB Probes being delicate, should be handled with kid gloves i.e. fit it gently but firmly avoiding the use of harsh tools such as hammer or pliers. The maximum tightening torque should be no more than 4 foot-pounds. The single-spacing washer that is provided should contact the carburettor casting, and the lock washer should be in contact with the shoulder on the probe.

Use counterbore to ensure the probe reaches all the way into the carburettor barrel. The counterbore will reduce the thickness of the casting slightly at the outside of the hole. Recommended torque is no more than 3 to 4 foot-pounds.

For more information on aircraft CRB probes, please visit https://www.jpinstruments.com/shop/crb-probe/

Optimization and Characterization of EDM 790 System

EDM 790The best EDM that money can buy in under ten thousand dollars (U.S) for 4 or 6-cylinder aircraft engine with transducers and all? The answer has to be EDM 790 manufactured by J.P. Instruments, U.S.A.

It’s not just an advert claim, the Engine Data Management 790 system is truly the most advanced twin piston engine-monitoring instrument on the market. The EDM 790 has been TSO’s for quality and is rightly thought of as a Flight Engineer and Maintenance Manager that has your back covered.

Covers to 29 critical parameters

Armed with the latest microprocessor technology, the EDM 790 will monitor up to 29 critical parameters of your aircraft engine – 4 times a second! It boasts of a linearized thermocouple accuracy of better than 0.1 percent or 2 F° and this boast has been tested and verified by the FAA.

It never sleeps

Constantly on the alert, the EDM 790 will keep an eye for you on 29 critical parameters that are automatically checked four times every second. No matter which screen you might be currently looking at, the EDM 790 will keep running checks on all 29 parameters in the background.


The EDM 790’s accuracy stems from its linearized thermocouples. There is nothing in the aviation market that compares to J.P.I’s linearized accuracy.


Two buttons on the faceplate is all that it takes to programme the EDM 790 or to access all its functions. Leaning is accomplished automatically using the Lean Find procedure. With the EDM 790 it is now possible to have substantially more diagnostic information available for your maintenance crew.

The Advantage of EDM 790

1. Computer Assisted Diagnostics covering the entire aircraft system from the cockpit. On detecting any error, the specific code is displayed.
2. Easy-to-use 2-button programming.
3. Twenty-nine parameters checked 4 times a second and this includes the EGT Gauges Differential, Alternator Voltage, Fuel Flow and Shock Cooling.
4. Displays variable Scaling of EGT Bar Graph.
5. Its amazing Lean Find Mode identifies the first and last cylinder to peak while the Peak Find with quick responding probes, automatically captures the EGT or TIT peak value.
6. Data Port for downloading of data.
7. The EDM 790 is the only FAA approved graphic engine monitor with a complete fuel flow system.
8. Temperature detection accuracy is ONE degree (even for EGT).
9. Paired with JPI’s “grounded” fast response probes.
10. Cooling rate and shock cooling checked on each and every cylinder.
11. EDM 790 features a “Normalize Mode” for accurate trend monitoring. Bars are in 10o increments.
12. Alphanumeric scanning display of 29 functions or channels.
13. TSO’s for Quality and Reliability with FAA, STC approved Fuel Flow.
14. Three-year warranty.

For more information, please visit: https://www.jpinstruments.com/shop/edm-790/

How Slim-line Tach Gauges Works in Aircraft?

Slim-line Tach GaugesThere was a time when portable watches used to be two inches in diameter and as much as three-quarters of an inch thick. These watches were kept in the pocket and taken out only when you needed to know the time.

We all know how these pocket watches evolved, became slimmer and turned into wrist watches. The display gauges in the aircraft cockpit underwent a near identical transformation except that; on the evolution time-scale, they evolved nearer the electronic revolution so instead of becoming slimmer versions of their earlier self, they turned into slim line digital gauges.

Naturally, the sensor that actually picked up the aircraft engine data also got transformed and began transmitting data in electrical pulses that could be interpreted by the smart electronics circuits inside the slimline gauges.

In next to no time the integrated circuits got so miniaturized that an entire circuit was fitted inside a single chip 2 x 1 cm in size which came to be called the IC chip (short for integrated circuit). During this same period, onboard memory was developed which totally transformed the way data was handled and interpreted because data could now be temporarily stored, recalled and used – almost in the same way as your calculator memory.

Next came a permanent memory module – the Random Access Memory (RAM). Thanks to this new development, instead of data being lost when the aircraft engines were turned off, critical engine data could be stored and retrieved on a semi-permanent basis.

Along with the miniaturization of the innards of the slimline gauges in aircraft, the front end i.e. the display itself underwent a change and the humble analog dial was replaced with a Liquid Crystal Display (LCD). So now the pilot could see the actual digits. This was also the time the analog wrist watch began to get replaced with a digital wrist watch. This was also the time when electronic pagers began to make their appearances in the market.

The next big development occurred when the memory modules was linked to the faceplate of the Slim-line Tach Gauges which totally revolutionized and enhanced the value and usefulness of the slimline gauge. The pilot could now directly interact with the gauge by feeding in alarm triggers in the form of upper and lower limits. For example, minimum temperature and maximum temperature. These figures would be stored in the memory module and constantly compared with the incoming temperature data.

So, if the temperature fell below the minimum figure or rose above the maximum figure, an audio-visual alarm could be triggered. This meant the pilot(s) no longer needed to keep monitoring the gauges and instead, could actually enjoy the flight.

Each slimline gauge usually displayed one piece of information. So, you had a slimline gauge for Oil temperature, OAT, RPM Sensor, Voltage, Manifold Pressure, OIL Pressure and so forth.

As of today, individual sensors pick up the data directly from the engine and transmit it as a voltage via wires to the individual slim line gauge for which it is meant. The electronic board and IC circuit onboard the slim line gauge interprets the incoming voltage, converts it into a meaningful number and displays it on the screen. The display was bright enough to be seen even with the sun directly behind the pilot.

For options on modern slim line gauges, please visit: https://www.jpinstruments.com/shop/slim-line-experimentalhomebuilt/

Characteristics and Operation of EDM-960 System in Aircraft

EDM 960The engine data monitoring system (EDM) 960 – the one manufactured by J.P. Instruments is available for all aircraft with 4, 6, 7, 8 or 9 cylinders engines. There are so many things in an aircraft that need to be monitored that in days gone by, there used to be a flight engineer whose job it was to keep an eye on the engine performance during flight.

But the flight engineer was only human and during long flights, it was easy to not notice some things. But being a machine albeit an intelligent one; the EDM 960 system electronically surveys everything it is connected to, and it does it four times a second. Nothing can escape its attention.

Some of the characteristics of the EDM 960 System:

The EDM 960 not only reads the data sent to it by the sensors, it has the ability to compare that data with extreme values pre-entered into the system by the pilots and; in the event that any sensor reading of the aircraft engine does not confirm to the pre-entered values, it will trigger an audio-visual warning.

Apart from this, if you plug the appropriate GPS, it can calculate time-to-empty in real time based on actual fuel in the tank. It can compute distance, calculate fuel requirement (based on current fuel use rate), compare fuel requirement with available fuel and display data on whether you can make it to a way-point or not.

The EDM 960 System acts like your very own flight engineer – one that never feels drowsy or sleeps during a flight.

Specifications of the EDM 960 Twin System manufactured by J.P. Instruments:

1. Lean Find™ finds the first and last cylinder to peak with true peak detect eliminates false peaks
2. Hands-free, automatic scanning
3. Displays both leaned temperature below peak and peak
4. All programming done from the Front Panel
5. Battery voltage with alarm
6. Programmable alarm limits
7. Amperes (load or charge/discharge meter)
8. Normalize view
9. DIF low to high EGT with alarm
10. Exhaust Gas Temperatures (EGTs) to stable 1°F resolution
11. EGTs to stable 1°F resolution 12. User selectable index rate
13. Shock cooling monitored on every cylinder
14. Fast response probes
15. Records and stores data up to 30 hours
16. Non-volatile long-term memory
17. Post-flight data retrieval
18. Data retrieval software
19. Download to Palm™ Computer
20. Fuel level display
21. Oil pressure
22. Outside air temperature
23. Oil temperature
24. Adjustable display
25. Adjustable order of display

Other characteristics of the EDM 960 System include:

Display via liquid crystal display (LCD) screen as well as remote auxiliary display (RAD) (if connected).

The default displays of the EDM 960 System include fuel pressure, oil pressure, oil temperature, bus voltage amps, fuel flow (left and right separately), and outside air temperature.

Without doubt, the EDM 960 is an invaluable safety device for the pilot and his aircraft. It helps diagnose engine malfunctions, adjust air-to-fuel mixture, provide real time feedback on the critical components of the Aircraft Engine Monitor as well as diagnose air craft position vis-a-viz destination and compare it to fuel status (provided you have the right GPS installed).

You can find more information here: https://www.jpinstruments.com/shop/edm-960/