We make your life easier Our quality has no limit We are unique & different

What Pilots and Maintainers Say About CDB

Craig Ernst – Test Pilot

The Customized Dynamic Balancing (CDB) process was a demonstration, not a test, which was conducted here at AATD on behalf of the Apache PM. The Apache PM had a "witness" present to observe and report his findings to the PM.
The CDB is a system/process that was designed by a Company called Shake'd Technologies and is marketed in the U.S. by Coker Logistics Solutions, Inc (CLS). It was CLS who solicited the Apache PM to allow them to demonstrate this system.
The concept of operation is simple. There are accelerometers temporarily placed in designated locations along the drivetrain, along with sensors to measure shaft RPM and vibration. The aircraft is then run on the ground and measurements are taken. All the data is pumped into a computer with the specialized software written by Shake'd technologies and a balancing solution is determined. Depending on the aircraft vibration condition, the driveshafts are balanced by indexing the driveshaft, adding weight tape to the inside of the driveshaft in specific locations.
We did CDB on two of our Apaches, AH-64A 120 and AH-64D 006. I have flown both and can tell you that it has made an obvious difference. Not only are the vibrations way down, it seems that the noise in the cockpit is quieter. We are impressed enough that we would like to arrange for these guys to return and do AH-64A 214 for us as it was not available during the demo.

CW4 George Wheeler – Test Pilot

First of all I want to say that the members of the CDB team have a very thorough knowledge of the AH-64 aircraft. Their ability to reduce vibration levels down so low and accurately has been able to increase the life of components and therefore reduce overall cost. With the modification of their equipment and the accuracy of their findings they have reduced the run times to just one adjustment most of the time. Which help us because it frees the test pilots to work on other issues.

I think this will be an excellent addition to the aircraft especially once it is incorporated into the MSPU. With the addition of sensors in other critical locations, it will further improve our ability to detect issues with the aircraft before it escalates to the failure of a component and possible saving lives and equipment. That in itself makes it worth having the program.

I hope that we continue to use this program and increase it's utilization to all our aircraft.

CW2 Tyson Le Roy – Test Pilot

Customized Dynamic Balancing has been an important tool in managing vibrations on the AH-64D. With the AVA, and with the much more accurate MSPU, we have been able to identify components that are potential sources of damaging vibration. At the unit level, the mission was to identify a faulty component and replace it. CDB has taught us that it is possible to reduce vibrations in individual components by managing the sum of vibrations on the system as a whole. This has saved our unit money, man-hours, and most importantly failures of the components. MSPU is an excellent tool in collecting data from the airframe, and identifying components that are near or have exceeded their thresholds. CDB provides a solution to the problem that MSPU identifies.

MSPU with the addition of CDB solution algorithms has been an effective system, which has set our test aircraft apart from our baseline aircraft. In our test aircraft, CDB has been effective in solving high frequency conditions experienced by our aviators. They were able to identify both non-rotating and rotating components that are not directly monitored. In one particular case, a loose tail rotor pedal bell crank, in another it was a bad precooler fan. Both are components that are not monitored, but have tell tale vibrations.

Beyond the ability to reduce vibration in the aircraft as a whole, CDB has had an important impact on the safety of the aircraftʼs monitoring system. Through the process of balancing the aircraft the team has identified eight faulty accelerometers. The problem is that the accelerometers are only put through resistance check, and are not checked for accuracy. So even if a component were to fail, it may or may not be flagged. This is an important issue that CDB solves in a creative way. Another problem with the system we have found is that if certain wires in the system break, they will prevent the illumination of the VIB GRBX caution message. Shaked has identified a number of broken wires. The identification of faulty accelerometers and broken wires has made the test aircraft a much safer airframe to our aviators.

Customized Dynamic Balancing is an important program in our unit. It has increased the safety and reliability of our test aircraft. My sole frustration is having access to this resource only for a few tail numbers. My goal is to see the whole battalion balanced.
It is a very difficult thing to identify a problem on one aircraft, and have no way to check the other airframes. The ability to troubleshoot rotating and non-rotating components without simply replacing parts is an important capability that should be released for use on the all twenty-four aircraft of 1-130th ARB.

CW3 John Piland – Test Pilot

My impression of CDB is great. I think this is great way to improve overall vibration in the drivetrain and reduce component wear. I can feel the difference; reduce in vertical IPS in the seat and inside the aircraft while adjustments are being made on the ground after each engine run-up. Our biggest vibration is coming from the rotor system. High time blades opposite from low time blades. Multiple blade repairs on the blades make the blade fly lower and you will run out of trim tab adjustment. Flying with weak trim tabs on the main rotor blade cause them to wash out during higher speeds. One reason is because of improper phasing and static balance of main rotor blades. The static balance is out of limits coming from depot on the last 4 new blades we got. Improper phasing comes from worn Main rotor dampeners there is no way to check for this on MSPU accurately or from the IETM. The lack of time to sweeten the main rotor versus get it with-in limits as per MSPU which is .30 IPS Max for the green.

I hope this system will be implemented into the MSPU software. I would like to see some of the limits on the Tail rotor balance, 90 deg, and IGB gearbox reduce. I understand why the Ah-64a the vib gearbox light came on more often then the Ah-64d MSPU equip aircraft because the limits are set higher on the Ah-64D. CDB found some Aircraft non-MSPU the vib gearbox light would not have came on because of bad accerlometer or processor. An indication inside the crew station that tells me which clutch primary or secondary is engaged. I would like to see the CDB train the 15R10 level at the schoolhouse and at the units on the importance of indexing the driveshaft's before you remove them. Teach the MTP what flight profile to fly and take a measurement to determine if you have a bad m/r dampener or not. How to check for loose APU mounts (we had three found prior to gunnery). Thanks again for the support and lessons learned from your TEAM of CDB personnel.