Case Studies of Flight Data Monitoring (FDM) Programs

Review real-world examples of flight data monitoring implementations, with lessons learned and best practices.

• Below Glidepath
• Frozen Brakes
• Hard Landings and Flap Exceedances
• FOQA/FDM Buy-in Key To Reaping Benefits
• FOQA/FDM Benefits From a Large Part 135 Operator

Below Glidepath

Review of FOQA data leads to safer landing technique

Professional flight departments often have a safety management system (SMS) program detailed in their operating manual with a paragraph similar to this one:

The purpose of ABC Aviation’s SMS is to manage risk, reduce the occasions for potential personal injury and material loss, and elevate safety awareness among colleagues.

The purpose is accomplished by:

• Establishing policies and procedures to ensure safe working conditions in all aspects of aviation operations.
• Identifying behaviors leading to unsafe practices, recognizing their potential for causing accidents, and developing solutions for mitigation of risk through effective safety management.
• Training personnel in proper use of equipment and procedures, and the importance of prompt reporting of potential hazards.
• Promoting a “Safety Culture” that encourages the exchange of essential safety-related information, establishes clear lines of responsibility and accountability, and analyzes the SMS’s effectiveness in reducing accidents and injury.

These statements all sound good, but how does collecting data improve safety? Doesn’t it just show all the mistakes you make?

ABC Aviation’s Operating Manual requires pilots to fly visual or instrument approaches according to stabilized approach criteria as defined and taught by their training provider. Two of those criteria are:

1. The aircraft is on the correct flight path.
2. ILS approaches must be flown within one dot of the glideslope and localizer.

Approach and landing are already higher-risk phases of flight. To measure the actual safety of their operations (Are we flying the aircraft the way we say we are?) and to discover any unknown risks in procedures or training, the company uses FOQA data.

The company’s FDM provider highlights sink rates greater than 1000 fpm, and deviations greater than one dot from the glideslope and localizer, if they occur below 1000’ AGL. If FOQA registers an event, the company’s FOQA Gatekeeper receives the information for review. ABC’s pilots are not expected to be perfect, nor is the real world always kind, but they are expected to follow procedures.

Accordingly, if they know or think they triggered a FOQA event, they are required to submit a simple SMS form to the Safety Officer who forwards it to the Gatekeeper. The Gatekeeper tries to match FOQA events with SMS forms and looks for common factors or trends.

In this example, FOQA data highlighted nine events over a four-month period for being greater than one dot below glidepath, below 200’ AGL. This potential risk got the Gatekeeper’s attention! No matching SMS forms were submitted. Review of the data eliminated any common factors, except that all occurred in VMC conditions and one pilot was part of the flight crew on seven of the events. FOQA data doesn’t show who was the pilot flying, so the Gatekeeper contacted the pilot to discuss the situation. Did he remember any of the events? Could this just be coincidence?

Due to the company’s Just Culture, the pilot felt no threat. He didn’t remember any of the events, but after the call, he looked up the flights in question in the company’s electronic scheduling system. He found he was indeed the pilot flying on all seven events.

The pilot had been flying for 38 years, had over 14,000 hours, and never had a violation or training issue. He had no explanation, but the data clearly showed he – and therefore the company – was accepting a risk he wasn’t even aware of!

The answer came a few days later while he was briefing the approach to his home field. One of the notes mentions the VASI and RNAV glidepath are not coincident, something he always briefs. While flying the approach however, he realized his technique in VMC was to follow the electronic glidepath until approximately 500’ AGL and then announce he was transitioning to the VASI. The difference between the two was slightly greater than one dot below on the RNAV glidepath!

Discussing it further with the Gatekeeper, they both agreed that while the aircraft was never in an unsafe situation, a better technique was to follow an electronic glidepath, when available, all the way to touchdown regardless of conditions. It is important to use data to improve safety and again, because of the Just Culture, the pilot happily briefed the situation at the next quarterly safety meeting.

Frozen Brakes

Review of FOQA data leads to pilot training and maintenance savings

This presentation from Flexjet details the benefits of FOQA including a case study where frozen brakes resulted in the use of the emergency brakes and significant tire damage. Using FOQA and other information, they were able to identify what transpired, which ultimately led to improved pilot and training department communications.

Permission to use this presentation granted by Todd Anguish, Flexjet.

Download the Flexjet presentation for the Air Charter Safety Foundation, March 2020

Hard Landings and Flap Exceedances

FDM leads to direct savings in maintenance costs

Monitoring hard landings and flap exceedances are great examples of FDM cost savings.

• Most OEMs have verbiage in the aircraft maintenance manual that only a pilot logbook entry defines a hard landing (as an example). Through the use of actual data, that maintenance inspection may be lessened or even eliminated if the limit is not exceeded or is classified differently (in Airbus terms – in a lesser zone).
• Flap overspeeds are another good example. A flight crew may not be aware of the overspeed at all or may misidentify the speed at which it occurred. Using the FDM data can help maintenance determine the level of inspection required, or if an inspection is required at all.

On one of my projects, I helped implement an FDM program with an air ambulance operator. One of their S-76s experienced an autopilot excursion (large lateral exceedance) that without data would’ve resulted in a $400,000 tail boom inspection/possible replacement, plus at least two weeks of downtime. Working with the OEM, the data identified the actual value was under the level that required a tail boom teardown therefore saving a great maintenance expense and kept the aircraft in service.

FOQA/FDM Buy-in Key To Reaping Benefits

Implementation leads to an array of safety benefits and savings

AC 120-82 and other industry publications such as UK CAA CAP 739 offer good guidance to implement an FDM program. One of the challenges in the “non-scheduled” world is that many workforces aren’t represented by a labor association. It may, or may not, be more challenging to execute a letter of agreement with buy-in from management and front-line personnel, and work within the confines of that agreement, without the assistance of an organized labor association.

Some of the lessons learned along the way with Parts 91/135 operators is the need to begin those discussions with the pilot group early in the process to get the “buy-in” needed. Examples include holding small group meetings with pilots to define the events. (Who knows better than the front line operators?)

Likewise, rather than a letter of agreement, a department could create a letter that both the employee and flight operations manager sign outlining the protections of the program. This letter is a great tool when on-boarding new employees to educate them on the program. The main goal is to avoid surprises when the program is launched. If all parties are on the same page, the launch and subsequent use will go much smoother. Nearly every operator that has found a “surprise” (or two) in the early phases of implementation.

Equipage

A fleet equipage survey goes a long way. This is another challenge in the Part 91/135 world.

• What equipment is currently installed?
• What equipment is available?
• What is the plan for a particular fleet? (Is it worth installing equipment if a fleet is being phased out?)

SMS and FDM

FDM is great at identifying hazards and quantifying risk (SRM). It’s also fantastic at identifying ineffective risk controls (e.g. unstable approaches without a go-around). For example:

• Are your department’s SOPS effective?
• Has the department considered “active” callouts? This question is based on crew contacts where the PM is “hinting and hoping” that the PF will go-around.

Safety promotion

Safety promotion is another strong point of FDM, since it can identify and tell the story of those events in challenging situations. In the Part 121 environment, there are ACARS safety alerts. At each airport with high unstable approach rates, the pilots receive a safety alert once the “in-range” message is sent. Likewise, this same information is published in the Airfield Briefing Guides, to highlight the “gotchas” such as the short distance from the Final Approach Fix (FAF) to the runway at El Paso’s (KELP) runway 22.

Maintenance

Operators enrolled in a “power-by-the-hour” program can provide FDM data to the OEM to verify that the engines are being operated as prescribed.

FOQA/FDM event lessons learned and successes

For those events meeting a certain threshold, Gatekeepers can reach out to pilots to learn more about a certain flight. As a Gatekeeper, I learn a lot of valuable info from crew contacts. Some successes include:

Excessive tankering of fuel to a Central American airport

FDM identified twelve events in a twelve-month period in which the flaps were extended above FL200. Ten of these events we identified to have happened at the same airport.

Through crew contacts, one Captain (who flew to that airport frequently) mentioned that the company had been “tankering” more fuel to this airport to reduce the need to upload fuel.

In addition to the increased fuel loads, it was common for Air Traffic Control to vector the aircraft off the arrival and slow the aircraft for traffic. The speed reduction would result in speeds close to the “Clean Maneuvering Speed.” To increase the airspeed margin above the stall speed, the flight crew would extend the flaps while above FL200.

As a result of these conversations, the company reduced the tankering to this airport. The reduction in tankering saw the instances of flaps being extended above FL200 significantly.

A bump in a overseas runway

Through hazard reports, pilots were reporting a “jolt” in the runway at a particular airport. Some reports described the jolt as strong enough to make the aircraft feel as if it would go airborne. FOQA data indicated the location of the vertical accelerations spikes. After coordination with two other operators, the location of the bump was confirmed. This information was shared with the airport, and the airport authority closed the runway and fixed the runway surface.

Both examples illustrate the value that the proper use and sharing of FOQA data can bring to flight operations. Further, FOQA data loses its value without the presence of a collaborative environment between front-line employees, department management and the aviation community.

FOQA/FDM Benefits From a Large Part 135 Operator

A large, Part 135 operation is working on implementing FOQA/FDM on a broader basis. Currently, they have FOQA on a subset of aircraft. Their analysis of the data has increased in the last six months.

Identifying specific risk and follow-up training

FOQA/FDM is providing insights into any unsafe operating behavior and safety related events.

For example, the flight crew self-reported a stick shaker event at a particular airport. Using the FOQA/FDM data, the operator was able to animate the flight. The event specifics were used in training under the Aviation Safety Action Program (ASAP) and will be used as a de-identified event for lessons learned. The operator is currently implementing required training for operating to the airport involved.

The positive use of the FDM data is building credibility in the FDM program.

SOP Compliance and Training

Another large operator implemented ‘spot checking’ observations of SOP compliance using FOQA/FDM data. The data from these spot checks was shared and used for monthly reviews of SOP adherence and to refine training and procedures of this operator.

Sharing of safety information between operators can have great benefit to all involved.

Management Buy-in and Engagement

An important aspect to these uses of FDM data was the buy-in from the Accountable Executive. The AE is aware and actively participates in these safety risk management activities involving FOQA/FDM data.