The world of rotary aircraft shares many of the same traits as fixed wing aircraft, but some key differences exist in each industry’s use of digital data. Even while exchange data standards like ATA 2200 and S1000D are available, the rotary world still generally lags behind on full integration and exchange of digital data. Yet as the rotary industry advances, manufacturers are increasingly being asked to provide source data to operators instead of traditional PDFs, DVDs, and printed material.
It is safe to say however that the rotary world is starting to catch up in using digital data to maintain maintenance activities. This process includes asking OEMs for digital data, using industry standard tools, updating OEM manuals directly, eliminating paper, and providing content to different device types and in standalone mode. In this post I’ll cover some examples of how the rotary and fixed wing industries manage data differently, as well as the trends pushing rotary operators to adopt digital standards.
Existing Data Standards
Data provided to rotary operators comes in many formats, such as:
For the most part, the choice of formats and delivery of data is driven by individual manufacturer capabilities and contractual requirements from its customer base. Quite simply, there aren’t many options offered for operators to choose from.
Key Differences from Fixed Wing
Predominance of PDF:
While most fixed wing manufacturers produce digital data using ATA iSpec 2200 or S1000D for common maintenance manuals (AMM, IPC, FRM, TSM, etc.), it is uncommon for rotary aircraft manufacturers to provide similar digital data. Most helicopter manufactuers use one or more of the common data standards internally, but generally produce unintelligent data for their customers. This presents a challenge for rotary operators to receive, review, and publish PDFs for internal use, especially if local changes need to be added or modified.
Less Predictable Schedules:
Helicopter operators by nature offer more dynamic flight services in more diverse operating conditions than their fixed wing counterparts. This creates challenges in maintaining digital content and records. Predicting due dates for maintenance events often requires complicated calculations that accommodate flight conditions (sandy, salty, icy, windy), flight payload, hoists used, etc. For example, here is how Agusta Westland’s calculates the effective flight hours for the main rotor blades on the AW139 helicopter:
(Flight Hours – Flight Hours over 6.8 Tons) + (Category A Training Hours * 2) + (High Wind Rotor Starts * 3.5) + (High Wind Rotor Stops * 3.5) + (Flight Hours over 6.8 Tons * 2)
Other components have similarly complicated formulas. This means the tracking system needs to maintain history of multiple operating conditions and the planning system must compute correct usage and adjust time limited inspections accordingly. By contrast, fixed wing operators typically treat flight hours, cycles, and days more predictably and equally (a cycle is a cycle is a cycle…).
MPD Items Stored within the AMM:
Rotary aircraft time limitations are almost universally included in chapters 4 and 5 of AMM rather than a separate MPD or Time and Limitations publication. Sometimes chapters 4 and 5 are physically separated into another document but just as often it isn’t. While the AMM structure allows this for fixed wing aircraft, a separate MPD is usually published for scheduled tasks and recommended intervals. One problem with the AMM approach is that adjusting time limitations is a critical process involving many approvals. Routing and AMM or sections of it for amendment and approval is more complicated than a dedicated time limits publication.
Parts are Defined in AMM with No Accompanying IPC Figure:
Some helicopter manufacturers bypass the use of an IPC and include part figures within AMM tasks. This can cause confusion or duplication, since a part may be used in several places or can only be located through tasks that reference it. The lack of an IPC is not universal across all the fleet types, and even within a single manufacturer some fleets have IPCs and some do not.
The number of Master Minimum Equipment List (MMEL) items (which define necessary items that must be operational for dispatch or conditions that allow temporary deviations) are much smaller for rotary aircraft. When compared to the MMEL of fixed wing aircraft, the difference is noticeable:
- A Sikorsky S76A helicopter MMEL has approximately 30 items
- An Airbus A320 aircraft MMEL has approximately 300 items
While MMEL items, AMM tasks, and routine job cards are lower in number in rotary aircraft; the same level of complexity exists for rotary operators. Reconciling service bulletin applicability, part interchangeability, tail number effectivity, and AD or SB accomplishment status are as rigorous in the rotary world as with fixed wing.
The Relationship Between OEMs and Operators
OEMs Aren’t Used to Operators Modifying OEM Content:
For that matter, neither are the operators. This becomes a problem for the operators to maintain approved maintenance tasks and MPD schedules while not modifying the OEM’s original data in the AMM. A common workaround is to create supplements that often are not clearly visible to the underlying task which places a heavy burden on the technician to look for related information. This is now changing as rotary operators become more adept at editing their own content and merging it with OEM content for publish to internal corporate websites with clearly visible links.
OEMs and IETPs:
It’s not unusual to see aircraft operators using 10 or more different interactive electronic technical publication (IETP) systems. This requires extra diligence and training for end users to understand different ways to find, refine, and present data. Another major problem with this is that helicopter operators often need to provide content in remote locations without reliable network access. Providing IETP content without company network or internet access often leads to DVD or paper distribution, which requires more effort to maintain up-to-date access to controlled documents.
Emerging Rotary Industry Trends
Sikorsky recently outsourced its digital data publication process to a company called ATP. This company receives digital data from the OEM and then packages it for operators in PDF format. This trend has had mixed results and reactions from the operator community.
More IETP-only Access:
This requires operators to train end users on multiple systems and doesn’t give operators the ability to re-use, expand, or modify the content easily. While this is convenient for manufacturers, it isn’t conducive for operators who want to simplify content delivery, presentation, and customization.
Digital Data Requirements:
For over 15 years fixed wing operators have received digital data from their manufacturers. Many tools exist for these operators to refine and amend content to their individual needs. Rotary operators are progressively moving to this maturity level and will surely expect the same level of functionality and benefits. Receiving PDF manuals won’t suffice as operators take advantage of new tools that use intelligent data.
Software used to manage rotary aircraft maintenance and flight operations data is moving towards the same level of maturity and functionality as solutions already common in the fixed wing world. This can be seen in recent adoptions by helicopter operators that include Ramco and SAP for MRO functions, AirVault for records management, and TerraView for technical manuals.
The need to access maintenance data in remote locations is leading helicopter operators to expect digital data solutions that are available anytime, anywhere. To overcome this, standalone solutions must be available to manage fleet and engine maintenance information. This need also extends to flight operations where network connectivity is even less prominent.