Unlike passenger airlines, there are no conciliatory sky miles to issue to the recipients of cargo carrier packages if the goods are delayed in transit.
For cargo carriers such as FedEx Express, the world’s largest airfreight carrier, profit margins depend on on-time delivery. If an aircraft is late, a package or delivery will be late as a result, and a refund must be issued to the customer that paid for an on time delivery of the detained package, cutting into revenues for the company.
FedEx Express is the world’s largest air freight carrier with a fleet of 650 aircraft, carrying an average of 4 million packages and 11 million pounds of freight to 375 airports in 220 countries and territories worldwide daily. To make sure the company’s aircraft fly optimum airspeeds, and engines operate to their maximum capabilities on every flight, FedEx has digitally customized and evolved its use of Boeing’s Airplane Health Management (AHM) platform over time. The operation connects aircraft ARINC 429 data streams to the AHM’s Graphical User Interface (GUI), which can be easily accessed by an airplane mechanic via their iPad or iPhone.
Here’s a snapshot of the operation that connects aircraft ARINC 429 data streams to the AHM’s Graphical User Interface (GUI) display that can be easily accessed by an airplane mechanic via their iPad or desktop.
1. The Boeing 777 has over 11,600 reportable faults. Couple this with over 270 prognostic alerts and EICAS Maintenance page access. The 777 is clearly the most developed AHM product.
2. Boeing 767: The aircraft live streams 531 different Boeing 767 Engine Indicating and Crew Alerting System (EICAS) messages and 13 different system reports using over 200 analog and discrete inputs.
3. Boeing 757: AHM is used to view a select number of critical engine and systems alerts. System reports are being developed.
4. The MD10 and MD11 AHM product monitors over 1000 CFD messages as well as ACMS discrete and analog inputs.
The onboard ACMS gathers data messages and streams them via ACARS to Boeing’s AHM staff, and Boeing crunches the data on the ground and makes it display on their web page.
Importance of GUI.
The Boeing 767 is a 1980s airplane using 1980s computer processing technology, admits FedEx Aircraft Health Maintenance Administrator Dean Gibson; but FedEx is using it in a modern way.
Boeing has updated the operating system periodically over the last two decades to keep its user interface fresh and easily adaptable to the way airframe mechanics and maintenance techs access the data displayed by AHM. Today, Boeing accomplishes the majority of that access by using a GUI on a desktop, laptop, tablet or smartphone. Boeing will also pass on to the airline everything they know about a fault found on a packet of data coming off the airplane and appearing on the desktops and tablets used by both their AHM back office personnel and FedEx’s global maintenance team.
“Boeing attaches everything they know about each fault, [such as] maintenance tips, fleet team digests or service letters to aid the person working the problem,” says Gibson.
In discussing Aircraft Condition Monitoring System (ACMS) programs with other airlines, Gibson has found that many carriers have developed in-house ACMS programs to pull data, but few had a useful way of making the data comprehensively “displayable.” This is where Boeing’s AHM program user interface comes in.
“AHM offers a user interface for uplink capability to communicate and interrogate aircraft systems during flight,” says Gibson. “These uplinks can be scheduled, which are event-driven uplinks [triggered or scheduled to be completed autonomously meaning no manual action needed] automatically, or they can be done on command in real time. One can also retrieve snapshots of systems taken by the crew manually. Development of custom uplinks can also be done. Common uplinks are for valve positions, temperatures, pressures, current software configuration, part number and serial number of avionics line-replaceable units installed, and flight control positions.”
The value in Boeing’s AHM platform is its ability to turn aircraft data into actionable information that maintenance staff can use to make timely, economical and repeatable maintenance decisions that aim to help improve the efficiency of their overall operation.
Digital Flight Data Acquisition Units (DFDAU) and ACMS software have always had the ability to allow maintenance staff to uplink and send a question to a digitally connected system on the airplane, but the GUI allows FedEx to do this without having to write software language. All that’s required from the technicians is that each is airplane-savvy enough to know what to ask for and why.
“We created a mobile app version of AHM [so that] certain folks do their jobs better. If you’re a fleet manager at an airline, you always want to know how the fleet is doing. A very important part of the use case for AHM is shared information throughout the flight operational enterprise. So, we greatly enhanced the notification capabilities, which means allowing customers a lot of versatility on sending specific types of messages to specific people so they can have instant awareness,” says Mike Hurd, program manager for Boeing Airplane Health Solutions.
A basic example of a GUI prognostic is how FedEx is able to quickly monitor its aircraft engine bleed air pressure. Through the GUI, AHM will send alerts to FedEx only when the engine bleed air pressure reaches a certain Pounds Per Square Inch (PSI) limit. Gibson also describes using the AHM algorithms to measure engine oil filter pressures.
“We obtain prognostics alerts before a part or system fails. For example, if an oil filter is considered to be bypassed, if it has a differential pressure of 1 PSI, a prognostic algorithm will monitor for a trend to 1 PSI, such as 0.5 PSI, 0.6 psi, .7 PSI or 0.8 PSI. This will give [the technician] the choice of how early [she] wants to be alerted to the trend. You do not have to wait for a failure,” said Gibson.
Reactive --> Predictive
While it’s great to take advantage of the technological capabilities of AHM, there is also a human-centric element to aircraft digital health maintenance. An airline can perform health monitoring by deploying a number of sensors on board, collecting the parameters, and then analyzing the health status of the aircraft and also predicting the life span of an electronic device, system or component. The earlier that FedEx can catch a problem, the easier it is to eliminate that problem before it leads to an aircraft stoppage.
According to Gibson, the challenge in changing from reactive to predictive maintenance using AHM is cultural. AMT’s previously began dealing with an issue on the aircraft when it arrives at their station, which is reactive.
“Maintenance Operations Control has had [to] change as well. Instead of answering a phone call from an AMT to go over a problem, you have a program telling you there is a problem. One must be proactive,” said Gibson.
Avionics, IT Modification
FedEx is writing some of its own software language for Boeing’s AHM interface and the air cargo carrier is also internally customizing the avionics on the new Boeing 767s that are being added the growing FedEx fleet every three weeks, according to Gibson. The airline has been able to optimize its fleet operations by modifying both the avionics and the computer software program for AHM.
On the Boeing 777s, Gibson says FedEx prefers the AHM maintenance enhancement software package, as this is the software option that allows the airline to download Engine Indicating and Crew Alerting System (EICAS) maintenance pages, similar to the way that paying for a premium version of a music streaming app allows the user to download any song from any album, whereas a lower cost version provides the user with a limited amount of access based on data bytes.
On the 767, specifically for FedEx, Boeing upgraded the EICAS operating system version 8 and added an AHM bus to the embedded architecture of the 767, which the OEM made available via a service bulletin to 767 operators. FedEx has also opted for the Teledyne 916 DFDAU, which Gibson said has 10 times the capacity as the older model DFDAUs. The air cargo carrier also added an Air Supply Bite Module (ASBM) BUS to export more data to the DFDAU.
On the Boeing 757, both Boeing and FedEx are developing ACMS software to improve its use of AHM for the fleet. FedEx is including a strict limit on the number of messages for which Boeing will alert them.
“For an aircraft model like the 757, [FedEx has] an aircraft condition monitoring system, and the retrofit required on the 757 is in fact putting our new health-monitoring algorithms onto that box. The airplane model that we’re newest to work on is actually the 757, and we’re working with FedEx to do AHM on their 757s,” says Hurd.
According to both Gibson and Hurd, aircraft equipped with Central Maintenance Computers (CMC) only require AHM software loading, while aircraft without it can require some hardware modification, and possibly additional sensors based on how an operator wants to customize their health management process.
There are direct correlations between FedEx expenditures and their use of AHM. According to Gibson, one of the largest ways the air cargo carrier saves money with AHM is by avoiding delays and cancellations. In turn, this allows the airline to avoid refunding customers for delayed packages.
“If a plane is having a problem within the first five to six hours of a flight, we can start moving parts from other countries to stage. We can get parts at the arrival location of the airplane before it gets there,” explains Gibson. “Previously, when a plane would arrive at a station that is when we would discover we need a part that may or may not be there. If you know in advance and we can ship a part from Hong Kong to Narita so that we don’t have to borrow something, that saves a lot of money,” said Gibson.
What happens next
At the end-user perspective, Gibson says FedEx sees the concept of the Onboard Network Server (ONS), a network of on-airplane systems that collects a high volume of airplane data and makes that data available to the airline, providing a future generational leap in AHM. ONS integrates data-rich airplane systems with optional connectivity systems, instead of requiring that the generated data be sent directly to Boeing’s ground-based AHM personnel.
“In the future data will be crunched on the airplane using an ONS or something similar. Only small amounts of data will be downlinked. Only what is the result of the data analytics software will be sent. Instead of transmitting all information via the [Aircraft Communications Addressing and Reporting System] ACARS and crunching it on the ground. Each airplane will have its own data cruncher and that could reside in ONS or something similar. They will be able to process information from the airplane like an onboard CMC that doesn’t interact with anything else, just operating in the background,” said Gibson.
This is especially true for the 787, which is putting operators up against a “data wall,” because the ACARS network cannot handle all of the data it transmits. According to a new white paper, produced by consulting firm ICF International, on aircraft data written by former Delta Airlines aircraft maintenance engineer Jonathan Berger, the 767 produces up to 10,000 aircraft health management parameters, while the 787 offers 100,000 parameters.
Luckily for Boeing operators, the OEM is investing heavily into providing new data links through which airlines can receive data without using ACARS in real time.
“It’s a big focus area for us. We’re taking multiple efforts on that. The one we’re working on today, called the non-ACARS interface, is to interface with the wireless gatelink and bring that data into AHM, so that data is coming to the ground and then bringing it ground-to-ground into AHM,” says Hurd. “Also, in terms of our avionics research development and different roadmaps with different airplane models, it is very important that we are looking to be able to enable our customers to leverage the data pipes that they have invested in. We want to do it in a way that is rather obscure and protective to the airplane. We have a lot of engineers focusing on that, but right now we’re leveraging the wireless gatelink,” said Hurd. AVS