Forum for Enhanced Reliability and Maintainability Standards (FERMS)

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FERMS Frequently Asked Questions

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What is FERMS?

The NBAA Forum for Enhanced Reliability and Maintainability Standards (FERMS) is a web-based tool that provides business aircraft manufacturers and operators with real-time information about business aircraft maintenance and performance. This database is available only to NBAA Members and select industry participants.

FERMS defines a framework for measuring the reliability of business aircraft. Strict formulas and definitions describe these measures in terms of dispatch reliability and operational availability. By collecting aircraft maintenance information submitted by aircraft operators via the web, NBAA can present aircraft technical data based on these new, industry-standard definitions.

Operators can enter relevant maintenance events for their aircraft, tracking the number of flight hours and landings at the time of each event. Using this information, and the dispatch reliability and operational availability formulas developed by NBAA, operators can view compiled FERMS data for their individual aircraft, their fleet of aircraft by model, their entire fleet of aircraft or the entire FERMS fleet for a specific model.

FERMS allows individual operators to benefit not only from the compilation of their own aircraft data, but also from information contributed by other experienced fleet operators. Users can mine the collected data, allowing for review and comparison of this valuable maintenance and performance information. For example, an airplane’s performance data can be compared to that for other aircraft of the same type, or to different types of aircraft in the FERMS database.

Introduced in January 2006, FERMS is the result of business aviation industry discussions held on future aircraft design goals, existing reliability research, as well as fleet reliability data from in-service experience. The Air Transport Association's Maintenance Steering Group 3 (MSG3) is practiced methodology for deriving maintenance tasks and intervals for transport category aircraft. MSG3 requires manufacturers and operators to have a feedback system that validates maintenance programs with factual data to justify program interval escalations or de-escalations.

FERMS provides a means for data collection and exchange designed to achieve product design and maintainability improvements for business aircraft. This is accomplished by establishing industry-accepted universal measures, collecting data based upon those measures, and generating reports from real-world operational data to share with manufacturers. Viewed another way, FERMS intends to do for aircraft reliability and maintainability what the NBAA's Range Formats (NBAA IFR reserves) has done for aircraft performance benchmarking.

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Why did NBAA develop FERMS?

FERMS will do for quantifying aircraft reliability and maintainability what NBAA’s Range Formats (NBAA IFR reserves) do in standardizing aircraft performance. FERMS dispatch reliability and operational availability definitions create an “apples-to-apples” comparison between manufacturers’ data and that of real-world flight operations.

Operators today collect data for unscheduled maintenance events, as well as routine maintenance. Collecting this data at an industry-central point will facilitate continuous aircraft surveillance for maintenance programs and aircraft reliability. This factual data will serve to validate reliability and maintenance programs, bringing about timely response to maintenance and operational issues. Dispatch reliability and operational availability measures will be reported in percent and event per hour and landings. For aircraft manufacturers, FERMS data will not only validate existing maintenance programs, but will assist service engineering in identifying corrective solutions to issues sooner. It will also help OEM decision makers in developing aircraft models that will achieve design criteria to meet and exceed past models availability performance. Operators will use FERMS to validate product selection decisions, as well to better manage operationally controllable elements.

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Who will benefit from FERMS?

Both aircraft operators and manufacturers will benefit from FERMS.

With this data, operators can evaluate the reliability and maintainability of their own aircraft compared to industry averages. FERMS gives small-fleet and single-aircraft operators access to accurate, real-time maintenance data that will help reduce costs and increase aircraft reliability by identifying emerging trends regarding component and system failures. This impartial, factual data can be used to support aircraft acquisition and operational management decisions.

Manufacturers will be able to review event data to quickly identify areas of improvement, and compare the reliability and maintainability of their aircraft compared to their competitors’ products. The ultimate goal is to have tangible data to influence future aircraft designs. The FERMS program will offer participants improved communications among operators, OEMs, suppliers and service providers.

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Who can participate in FERMS?

All NBAA Member Companies that operate aircraft are encouraged to participate in FERMS. The NBAA Member Representative may log in to enter maintenance event data, or may designate other contacts at the company who are eligible to enter maintenance event data.

Non-Members and NBAA Members without aircraft are not eligible to participate or view FERMS data.

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What maintenance events should be logged in FERMS?

With a few exceptions (See What maintenance events should not be logged in FERMS?), all scheduled, unscheduled and planned maintenance events should be logged in FERMS.

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What maintenance events should not be logged in FERMS?

The following categories of non-chargeable maintenance event should not be logged in FERMS:

  • Malfunctions, delays, cancellations or failure of the aircraft, its systems or components, caused by accidental damage, foreign object damage (FOD), random events: (e.g. bird strikes, lightning strikes, weather), misuse, neglect or unauthorized repairs.

  • Malfunctions, delays, cancellations or failure of the aircraft, its systems or components, attributed to the use of non approved spares or equipment.

  • Deferrable snags: which may be deferred within the terms of the MEL or CDL . Note that if the amount of time required to clear such a snag in accordance with the MEL/CDL makes it impossible to avoid a delay, then the delay would be counted as chargeable - but it is expected that the MEL/CDL would normally preclude a cancellation.

  • Replacement of Time Limited parts at their time limit or wearout parts at their wear limit will not be used as a reason for a delay or cancellation.

  • Prolonged Overnight Maintenance: When overnight maintenance is not completed in time for the first flight of the day.

  • Modification Action: Where scheduled maintenance (including modification action) that could be performed during overnight maintenance is instead performed during daytime operational hours.

  • Post flight squawks not corrected prior to the next scheduled flight when time permitted.

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Can I enter multiple entries with the same date, hours and landings?

Yes, however, this requires special handling; regardless of how much time taken to resolve each item, only the total accumulated time for aircraft out-of-service is measured. The combined downtime for all maintenance events on a particular day should not exceed the aircraft's total time out of service for that day. FERMS measures operational availability, not total man-hours.

For example, if two maintenance actions are accomplished concurrently in a six hour period and each takes four hours, two individual maintenance event can be added, each with 3 hours of downtime. Or if a particular maintenance event has higher priority than the other, and needs to be tracked closely, the actual time to resolve the item can be logged for the primary maintenance event, and the remaining balance of the overall downtime can be used for the second event.

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How long does it take to enter a maintenance event?

Once aircraft have been set up in the FERMS database, it will take less than 30 seconds to enter a single maintenance event after logging into FERMS.

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When should the trip impact of “Delay” be chosen for maintenance events?

“Delay” should be selected if the actual aircraft departure time occurs more than 30 minutes later than the scheduled departure time.

The rationale for the 30 minute window was determined by the average amount of time it takes to exercise a MEL deferral process. For example, if the deferral takes more than 30 minutes, that would be counted as a delay even though an MEL deferral is implemented.

Delays should not be selected for maintenance events that meet any of the following conditions:

  • Malfunctions, delays, cancellations or failure of the aircraft, its systems or components, caused by accidental damage, foreign object damage (FOD), random events (e.g., bird strikes, lightning strikes, weather), misuse, neglect or unauthorized repairs.

  • Malfunctions, delays, cancellations or failure of the aircraft, its systems or components, attributed to the use of non-approved spares or equipment.

  • Deferrable snags, which may be deferred within the terms of the MEL or CDL. Note that if the amount of time required to clear such a snag in accordance with the MEL/CDL makes it impossible to avoid a delay, then the delay would be counted as chargeable. However, it is expected that the MEL/CDL would normally preclude a cancellation.

  • Replacement of time-limited parts at their time limit or wear-out parts at their wear limit will not be used as a reason for a delay or cancellation.

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When should the trip impact of “Cancellation” be chosen for maintenance events?

“Canceled” is selected if the maintenance event causes the trip to cancel.

Cancellations should not be selected for maintenance events that meet any of the following conditions:

  • Malfunctions, delays, cancellations or failure of the aircraft, its systems or components, caused by accidental damage, foreign object damage (FOD), random events (e.g., bird strikes, lightning strikes, weather), misuse, neglect or unauthorized repairs.

  • Malfunctions, delays, cancellations or failure of the aircraft, its systems or components, attributed to the use of non-approved spares or equipment.

  • Deferrable snags, which may be deferred within the terms of the MEL or CDL. Note that if the amount of time required to clear such a snag in accordance with the MEL/CDL makes it impossible to avoid a delay, then the delay would be counted as chargeable. However, it is expected that the MEL/CDL would normally preclude a cancellation.

  • Replacement of time-limited parts at their time limit or wear-out parts at their wear limit will not be used as a reason for a delay or cancellation.

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What is the definition of “Downtime Hours?”

Downtime starts when the aircraft is not available due to maintenance. Downtime shall end when the aircraft is returned to service in accordance with regulations. Downtime shall include administrative and logistics delays such as but not limited to:

  • Downtime due to lack of spare parts
  • Downtime due to lack of facilities (e.g. Service Center)
  • Downtime required to complete all regulatory paperwork
  • Downtime due to lack of qualified personnel
  • Downtime due to Maintenance Organization not operating on a 24 hours/7 day per week schedule

When several maintenance tasks are conducted in parallel, the total downtime shall not exceed the elapsed time. See Can I enter multiple entries with the same date, hours and landings?

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What is the definition of “No Impact?”

“No Impact” is selected for all maintenance entries that do not meet the criteria for a delay or cancellation (i.e., scheduled maintenance events).

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What is the definition of “Total Time?”

The total time is the elapsed calendar time, in hours, from the aircraft's "Starting Date" and the date of the most recent maintenance event.

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What FERMS reports are available to aircraft operators?

For aircraft operators there are three main reports:

  • FERMS Reports by Aircraft
  • Review Maintenance Events for My Aircraft
  • Review Maintenance Events by Model

On the FERMS Report by Aircraft, operators may select an individual aircraft in their fleet and compare it with another aircraft in the fleet, their fleet of aircraft by model, their entire fleet of aircraft, or the entire FERMS fleet for a specific model. FERMS Report by Aircraft includes the following data for each aircraft selected:

  • Total flight hours
  • Total downtime hours
  • Total landings
  • Total delays
  • Total cancellations
  • Total maintenance events
  • Flight hours per event per aircraft
  • Landings per event per aircraft
  • Dispatch reliability
  • Operational availability

On the Review Maintenance Events for My Aircraft report, operators can review all of the maintenance events for a particular aircraft. Each event includes the following:

  • Event date
  • Aircraft landings at the time of the event
  • Aircraft hours at the time of the event
  • Downtime hours for this event
  • System ATA
  • Trip impact (delay, cancellation or no impact)

The Review Maintenance Events by Model report provides the same information as the Review Maintenance Events for My Aircraft report, but combining all of the maintenance events for a particular aircraft model.

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How is dispatch reliability calculated?

Dispatch Reliability = Landings - Delays x 100 (in percent)

Landings + Cancellations

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How is operational availability calculated?

Operational Availability = Total Time - Total Downtime x 100 (in percent)

Total Time

Total time is the elapsed calendar time from the aircraft’s FERMS start date to the latest event date. Total time is measured in hours.

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How do I add aircraft to my NBAA Member record?

To add an aircraft, log into FERMS and then click on “Add an Aircraft” on the FERMS welcome screen.

NBAA Member Representatives and FERMS contacts may add company aircraft that are not current listed in the NBAA database. (Note: aircraft changes may affect NBAA Membership dues calculations for your next billing cycle.)

The following information will be required to add an aircraft:

  • Aircraft registration number
  • Home-base airport (three-letter identifier)
  • Serial number
  • Starting hours
  • Starting landings
  • Starting date

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How do I edit/remove aircraft from my NBAA Member record?

To edit or remove an existing aircraft, log into FERMS and then click on “Edit/Delete” next to the aircraft.

Operators may edit the “Aircraft Registration Number” and “Home Base Airport” fields for aircraft already in the NBAA database. To make other changes – model, serial number, etc. – operators must delete the existing aircraft then re-add the aircraft with the new information.

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How do I add additional FERMS contacts to enter event data?

NBAA Member Representatives may assign additional contacts at their company to be FERMS contacts. FERMS contacts may add/edit/delete maintenance events and add/edit/delete company aircraft. (Note: aircraft changes may affect NBAA Membership dues calculations for your next billing cycle.)

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Who will be able to view my FERMS data?

NBAA Member Representatives and FERMS contacts will be able to view FERMS data for their company only. OEM FERMS contacts will be able to review maintenance event data for the aircraft manufactured by their company; they will not be able to review maintenance event data for aircraft manufactured by other companies. Aircraft registration numbers will not be shared.

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Will the aircraft manufacturers be able to correct FERMS event data?

OEM FERMS contacts will be able to review maintenance event data for the aircraft manufactured by their company. They will use the data to identify problems areas and verify that event submission meet the FERMS guidelines. If an OEM FERMS contact finds an event that needs to be corrected or deleted, he or she may “Report a Discrepancy” for this event and offer a suggested correction. The operator then may accept or reject the OEM suggestion. NBAA staff members will serve as mediators to resolve disagreements between operators and OEMs.

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Who can I contact for more information about FERMS?

For more information, contact NBAA's Eli Cotti at ecotti@nbaa.org.