Checking required safety clearances are maintained when a 737 MAX 10 taxis into an apron area at Frankfurt Airport.

AeroCENTRAL Specifications

Tobias Pinzl from Fraport AG highlights some of the initial questions when beginning an operational assessment of a new aircraft: “Are the taxiways wide enough? Will there be any risks due to jet blast impact? Will there be new dependencies in the operational use of aircraft stands?”. 

The answers to these, and many other questions, can only properly be answered by using advanced applications. “It’s impossible to do analysis and simulation without software today,” Pinzl says. “As a first step, we compare the new aircraft type with similar aircraft types or the corresponding previous versions.” 

Fraport uses Transoft Solutions products. AeroCENTRAL Specifications the successor to the company’s Aircraft Data Viewer desktop product, contains comprehensive data and characteristics for an initial comparison of dimensions, service points, and jet blast impacts. Planners can access AeroCENTRAL Specifications online to view aircraft dimensions, and other important characteristics. Users can view and compare measurements in top, front and side views, including door positions, service point locations, and jet blast contours. 

AviPLAN simulation

Transoft’s AviPLAN software can then be utilized to undertake more sophisticated modeling. AviPLAN’s simulation capabilities allow a detailed investigation of aircraft movements (especially in taxiway curves) and the operational impacts of complex docking scenarios.

Pinzl notes: “You can imagine how an aircraft might move – AviPLAN shows us how the aircraft actually will.”

AviPLAN’s advanced optimization functionality enables contact and non-contact stands to be planned to an unrivalled level of detail, including those with multiple lead-in lines and passenger boarding bridges (MARS). AviPLAN provides warnings to indicate when parameters are nearing, or exceed, design limits. It also models accurate pushback maneuvers – users can accurately simulate complex aircraft-towbar/towbarless tractor pushbacks in 2D and 3D, to define new or verify existing operational procedures. The powerful AviPLAN maneuver simulation tools enable users to define and adjust parameters such as aircraft/vehicle type, turn types and angles, construction points and offsets, speeds and more. It can be adjusted, and optimized, on the fly.

Checking jet blast impacts and clearances

Pinzl gave an insight into the capabilities AviPLAN provides for Fraport: “I can determine wing tip clearances that are necessary for the aircraft, then I can check jet blast impact that might pose risks to people, equipment and infrastructure.”

Assessing jet blast impact on neighboring apron areas when a 737 MAX 10 leaves an aircraft stand at Frankfurt Airport.

“Then I can check operational elements – are the passenger boarding bridges long enough? Are the angles and slopes okay? What about underground connectors for fueling? Is the ground power within operational range? Basically, I can simulate the whole ground operation, including ground handling, on the aircraft stand.”

Evaluating whether aircraft stand dimensions are sufficient and ground handling operates without conflicts at Frankfurt Airport.

Operators can check that the required clearance distances between aircraft stands and surrounding buildings/equipment to the wing tips and main gear are maintained. AviPLAN can also model specific operational scenarios in detail. Pinzl explains: For example, you may have a catering truck trying to reach the front door, while cargo is being loaded. “I can look at those processes, and check whether there might be conflicts, or whether there’s enough area around the processes, so that vehicles can safely move around, and there will be no problems later in real operations.” Pinzl appreciates the detail AviPLAN’s simulations provide – and the intelligent airside planning it enables.

He notes: “The algorithms allow me as a planner to simulate different kinds of movements – for example, is there a slight difference between a pilot steering the aircraft, and the aircraft being towed by a pushback driver?”. AviPLAN users can simulate specific angles, and speeds, of moving aircraft/vehicles, and analyze the impacts. “From our experience it comes notably close to the real taxi behavior on the airfield,” Pinzl emphasizes. Even small differences in aircraft/vehicle steering “can have huge consequences”, he points out, “because basically it’s whether you’re compliant to your regulations or not.”

Regular aircraft library updates are provided, which keeps planners up to date with the changes made in manufacturers’ planning manuals for aircraft types already in service, for example, steering limit restrictions, to ensure AviPLAN simulations remain accurate.

“I can simulate those steering limit restrictions,” Pinzl says. “I can say, ‘ok, I’ll put a maximum limit on the steering angle of 80% – and the resulting taxi behavior is simulated exactly. The benefit is knowing exactly how aircraft, and vehicles, will move: “It helps us use the available space on the apron efficiently, we can ensure necessary safety distances, and use everything outside those areas for other operational purposes.” Pinzl adds: “It’s a huge improvement compared to the past. We don’t lose space – we can plan exactly, according to the safety distances we need.”

Frankfurt Airport utilizes the software in response to questions that might emerge in daily operations or something outside standard procedures, for example in connection with construction or maintenance activities on the airside. “We can quickly check and help the operation,” Pinzl says. “We can simulate everything that’s happening on the airfield with results that are very close to reality.”

New aircraft

Fraport utilized Transoft Solutions products to undertake operational assessments of two new Boeing airliners, the 777-9 and 737 MAX 10. Pinzl says “it is easy to understand” a requirement to check the impact of the 777-9. This latest 777 is Code E compatible like the current 777-300ER – but the 777-9 is 76.7m long, some 2.9m longer than the current-generation aircraft.

The 737 MAX 10 might appear less challenging, but Pinzl notes: “A look at the characteristics shows its operational approval is a complex task as well. With a length of 43.8 meters, the 737 MAX 10 is approximately 1.7 meters longer than the 737-900.” He points out: “Even though the wingspan is unchanged, compared to the 737-900, the length of the 737 MAX 10 and the resulting taxi behavior in curves leads to large differences in the required safety distances between adjacent objects and the taxiway centerline.” Pinzl continues: “According to EASA CS ADR-DSN.D.240, increased clearance distances are required for this aircraft type, as it has a wheelbase of more than 18m.” Unlike other Code C aircraft (e.g. A321, 737-900), a safety distance of 4 meters instead of 3 meters to the main gear must be ensured.

“In cases where the main gear clearance cannot be maintained, taxiway markings (e.g. taxiway edge markings) and, if necessary, taxiway edge lights must be adapted,” he adds.

AviPLAN software helped Fraport planners check whether the required wing tip and main gear safety clearances would be maintained if a 737 MAX 10 taxied into an apron area, and also assess wing tip clearance while entering the aircraft stand. AviPLAN modelled the jet blast impact of the 737 MAX 10 – specifically, to see if there were any safety problems when the aircraft taxied into/away from a stand on neighboring apron areas. Fraport also utilized the software to check whether stand dimensions were sufficient and whether ground handling could work without conflicts. In one case, it highlighted that the aircraft tail and passenger boarding stairs projected into the taxilane, which is not approvable.

Identifying a conflict where the aircraft tail and passenger boarding stairs project into the taxilane.

Overall, Pinzl says: “It is important to closely monitor the development of aircraft by manufacturers so that new requirements can be considered at an early stage when planning new and redesigning existing airside infrastructure.” He emphasizes that reliable information on aircraft types and the technical capabilities of modern simulation software is “crucial to be able to deal with these aircraft developments in the best possible way.”

Pinzl says Transoft’s software is “a main tool for demonstrating EASA compliance, contributing greatly in our efforts to maintain EASA certification. You can simulate everything to a very detailed level. ”He concludes: “AviPLAN is very convenient to use for checking your infrastructure, whether it’s compliant, not compliant, or whether we might have any operational problems. It’s essential for us.”