Rotor and Wing Aviation Services - Cairns, Queensland, AustraliaRotor and Wing Aviation Services - Cairns, Queensland, Australia

Blade Management

Rotor Track and Balance  – Blade Balancing – Blade Management



Rotor Track and Balance – Blade Balancing – Blade Management


Blade Management

Traditional Rotor Track and Balance and rotor blade management has always focused on the Dynamic Track and Balance (RTB) to get a flying “set” of blades. Unfortunately, most helicopter operators and indeed some manufacturers, believe that flying “sets” of blades is the only acceptable way of managing a rotor blade population. This is being done in an effort to remove the possibility or to at least control the occurrence of “rogue” rotor blades. Rogue rotor blades are generally caused by span moment arm migration among a fleet of blades. This can be remedied by performing an accurate static blade balance with tip weight adjustments – providing you have the tooling.

By changing emphasis to Static Balance Blade management followed by Dynamic Rotor Track and Balance, rotor blades will become far more interoperable and remain in service for far longer period of time than currently is the case. Blades will not be returned needlessly to overhaul centres because “they will not fly with other blades”. They will be managed instead at operator/hanger level.

Maintenance manuals have identified for many years the limitation of this process. They have clearly stated that if the Rotor Track and Balance (RTB) results in the move line passing tangentially to the zero axis – this is the best you can reasonably expect leaving you with one of two options:

a. You must accept this result and the resultant vibration level, or
b. change a blade.

– the blades will not fly together.

This phenomena is often typified by charts as similar to those below.


Tangential Move lines typical of Rogue blades,static balance, blade management, dynamic blade balance


Tangential Move lines typical of Rogue blades,static balance, blade management, dynamic blade balance


The first question which should have been answered many years ago is: WHY won’t these blades fly together?


WHY?:          These blades will not fly together primarily because of a mismatched Span Moment Arm.


A new approach to Blade Management needs be adopted based on the control and correction of Span Moment Arm migration of operational blades at operator level if improvements to Rotor Track and Balance (RTB) efficiency are to be Go to Topobtained.


Current/Traditional Blade Management

The traditional approach never looks at the entire balance solution. It only ever uses the Dynamic RTB to balance a rotor. The solution must incorporate BOTH Static  & Dynamic balance to achieve an efficient result.

Traditionally blades were attempted to be matched by a number of administrative methodologies such as matching hours flown on each blade, matching serial numbers or a combination of both. Whatever method, more often than not, it boiled down to a time consuming trial and error process to find a matched set of blades that would fly together.

On multi-bladed systems, static balance is only ever done properly when new or when the blade is sent for a major overhaul at an approved blade repair centre which has a physical master blade.

On teetering heads such as the UH1, operators perform a simple “see-saw” or pivot balance. The limitations of this procedure are listed elsewhere on this site. The result of this method however is that it only promotes the use of “sets” of blades – it does not provide a means of making all blades interchangeable. This method of static balancing also is limited by using the Dynamic adjustment weights/stations to correct for a static problem – thus reducing the amount of dynamic adjustment available to solve dynamic problems.  

This technique will ultimately create the “rogue” rotor blade….this is part of the problem that has consistently plagued the industry and created such needless cost, frustration and waste of both time and money.


Dynamic and Traditional static adjustments on teetering head,static balance, blade management, dynamic blade balance,static balance, blade management, dynamic blade balance
Red: Static/Moment Balance Correction Weights
Blue: Dynamic RTB Lateral Correction Weights


The traditional blade management process allows the Span Moment Arm of individual blades to migrate – UNDETECTED. This results in mismatched blades.


Typical Span Moment Arm Migration

Lets follow the path of this migration and how it reduces the dynamic weight adjustment progressively to the point where blades become unflyable with other blades.

Teetering Head


Do any of the above scenarios sound familiar to your own experiences? If so, you may want to consider adopting a New Blade Management system and routine Static Balancing on the hangar floor.



Traditional static balance procedure


New Blade Management

With the identification of the cause of Rogue Blades, it is now clear that a new approach to blade balancing or more precisely – Blade Management needs to be adopted.

The traditional inefficiencies and cost can no longer be afforded by an industry where capital costs and Direct Operating Costs are very high with a disproportionate pressure to keep charge-out rates very low forcing very thin profit margins. Defence and Government air wings are not immune from the drive for “more bang for the buck”. Shrinking budgets worldwide coupled with the accompanying political pressure necessitates that these organizations think more commercially and seek more flying hours per maintenance dollar.


New Blade Management Procedure

We have always treated Static & Dynamic balancing as two totally different, unrelated exercises – they should not be.

A successful Dynamic balance is very dependant upon a good Static balance – most importantly – the Span Moment being maintained within a reasonable tolerance of the ideal “Spec” figure if blade interchangeability is to be assured and if the full benefit of the dynamic adjustments are to be provided to counter any dynamic problems.

This New Management procedure does not advocate that a static balance needs to be done every time a Rotor Track and Balance (RTB) is done.

It is based on a periodic static balance to particularly check Span Moment Arm, whenever scheduled routine maintenance is carried out in the existing servicing schedule – no additional maintenance is called for. It is recommended at routine maintenance on or about every 500-600flt hrs (or after blade repair/painting). This will ensure Span Moment Arm Control within tight limits and enable trouble free RTB and remove “rogue Blades” from your fleet and inventory blade stock ensuring total blade interchangeability across your fleet.

For a comprehensive Blade Management plan see the download page.


Potential Cost Savings

The US Army is projecting a savings of more than U$1.0M per year at Corpus Christi Army Depot alone by using this technology. See Redstone US Army Cost Savings Free Download for details.

A cost benefits analysis spreadsheet is available free, to assist in quantifying potential savings.


Converting to a New Blade Management System

See the Rotor Blade Management Free download.

Converting from a Traditional Blade Management plan to a Static Balance Blade Management Plan is simple, easy and straight forward. Cost is minimal in capital outlay – this cost easily recovered with the reclaiming of even one rotor blade. There is effectively no man hour cost since in the mature Static Balance Blade management Plan, static balancing is done during scheduled maintenance when blades are already off the aircraft. The Static Balance itself takes no more than 10 minutes per blade.

Strategic positioning of tools ensures that blades can easily be passed over a static balance on a routine basis. Avion/Avtask has without doubt, the best main rotor blade and tail rotor blade static balance tools in the industry. Their tools are in widespread use throughout the US Army and many other global Defence Forces. Civil operators include Columbia Helicopters. These tools are ideal for operators of civil CH47, UH60, UH1 and many other models of helicopters.

After the initial introduction and resetting of a fleet of blades back to OEM specifications, this be maintained by periodic checking. This period is normally set to align with an already prescribed scheduled aircraft service. The period is determined by assessing the rate of span moment arm migration that the fleet’s rotor blades may experience. This is largely a factor of the environment in which the blades/helicopters are exposed or operated in. For example, a sandy, dusty, highly erosive environment may require more regular periodic checks such as every 500hrs due to regular paint touch ups in the field and blade erosion.   Similarly, operations in rainy, wet environments where aircraft are left standing exposed to high rainfall may suffer from trapped water problems, depending upon the model of blade and its susceptibility to trapped water.

Blade Admin/Paperwork

Significant simplification of blade paperwork and administration is achieved. Individual tracking of blades to achieve a “flyable” set is eliminated. Any blade out of the box should fly with existing in-service blades. Paperwork is summarized by computer generated printouts detailing the date, initial blade results, subsequent adjustments performed and the final blade mass, Span & Chord Moment arms and CofG. Potentially large numbers of administrative man hour savings are Go to Topachievable. 

This simplification of blade paperwork allows for easy introduction of a Static Balance Blade management system with reduced man hours for maintenance control personnel. 



New Blade Management Summary


Advantages of Operator Static Balancing



Try it and reap the benefits, financial rewards and competitive edge. 


For more advantages, see Free Rotor Blade Management download.



CH47 Columbia helicopter, static balance, blade management, dynamic blade balance

CH47 Columbia helicopter

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