Flight Data Monitoring (FDM) programs monitor the action of an aircraft during flight. This is typically achieved with data acquisition and storage hardware and post flight data analysis software. The data generated from FDM is generally used to improve operational efficiency and safety and reduce maintenance costs. The Flight Data Monitoring FDM program will allow to identify areas of operational risk and quantify current safety margins by highlighting occurrences of non-standard, unusual or unsafe circumstances. This process is part of ICAO Annex 6 – Operation of aircraft. FDM is mandatory on airlines operated under European EASA jurisdiction whose aircraft mass is greater than 20 tons.
Such program may have different name and acronym:
Flight Data Analysis (Program): FDA or FDAP
Flight Data Monitoring program: FDMP
Flight Operations Quality Assurance: FOQA
Flight Data Monitoring FDM covers a set of core events established in the main areas of interest for the different flight phases (Taxi, Take-off, Cruise, Descent, Approach and Landing). Flight Data Monitoring software collects and analyzes aircraft operational parameters that are recorded on board the aircraft typically using Quick Access Recorder (QAR). QAR can typically record a large number of aircraft flight parameters (such as IAS, AOA, accelerations, heading & …). They are downloaded periodically when the aircraft reaches a suitable station or maintenance base. The resulting data is stored in a large database and analyzed to identify occurrences that exceed defined thresholds, and resulting trends.
Data is processed by software that provides a corresponding series of flights and flight events to the end user. Filtering those flights and events is necessary to ensure a good level of relevance and consistency in the database. Undesired events to be cleaned are generally recurrent and may be due to several factors such as improper thresholds or event definition under some circumstances (for instance in case of training flight or steep approach) or inaccurate terrain database (GPWS “undue” warnings or noises). Even though such spurious events have to be cleaned to ensure a good quality of the database, their root cause needs to be identified and corrected when possible.
Analysis is the core of the FDM process. The simplest way to look at it is to monitor the occurrence rates and trends of the various events configured in the software (for example number of hard landings in a month). Typically, a high occurrence rate of one specific event should be investigated. Analyzing a trend of occurrence rate over a large period of time requires the knowledge of any change in the company that can impact this rate (change in SOP, change in routes or airports, change in FDM algorithm or thresholds, specific training given to the crews, etc.). The analysis consists in putting those numbers or occurrence rates in perspective.
The FDM process inherently belongs to the Safety Management System (SMS) of an airline. FDM is an efficient input to SMS for flight operations.
The principle of the SMS in an airline is to:
- Collect occurrence data;
- Identify hazards;
- Assess the risks (by combining the likelihood of occurrence and the possible consequences of each hazard);
- Identify and put mitigation measures in place;
- Monitor the efficiency of the mitigation.
FDM provides the capacity to analyze a wide range of parameters and to identify contributing factors that will help to assess and understand the root causes of in-service incidents – in complement to flight crew reports or interviews. Since FDM gathers the data of the complete airline or fleet, the analysis provided in a weekly or monthly report enables one event to be analyzed in a general context instead of being focused on that single particular event. The objective of setting up an FDM process in an airline is to transition from a purely reactive mode (incident analysis based on flight crew reporting) to a more proactive mode (early identification of undesired events and implementation of mitigation measures).