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On Base: Testing and Maintaining the F-35 at the PAX ITF NAS Patuxent River, Maryland // March 27, 2015 A 5th Generation fighter jet like the F-35 cannot begin to help secure our skies without first being pushed to its limits in rigorous testing. This means putting the Lightning II through scorching heat, frigid cold, hard-impact landings on the decks of aircraft carriers and careful touchdowns on wet runways. Throughout the vast array of tests, engineers at Naval Air Station Patuxent River (PAX) Integrated Test Force (ITF) in Maryland constantly monitor each part of the jet to ensure that all of the systems work together as they should. Brittany, an early career engineer, is one of the many engineers supporting flight test activities at PAX. Brittany’s role in flight test heavily focuses on monitoring and improving how the F-35 engine and lift fan interface with the rest of the aircraft. The Pratt & Whitney engine—capable of generating up to 40,000 pounds of thrust—creates heat as a by-product of its power. As it is carefully nestled in the back of the jet and immediately surrounded by critical hardware, Brittany must constantly monitor the area during testing and ensure all thermal readings are within normal limits. On the B variant, she also helps verify that the drive shaft—which spins the lift fan—is functioning properly. Brittany’s daily work on these integral elements of the jet allow her to have a unique hand in the success of every F-35 Lightning II that she and the PAX team test. Each time they encounter an unexpected result or challenge, Brittany and the flight test team must innovate and adjust their approach to problem-solve in real time. “I know for every test point we complete, we are constantly expanding the envelope of what the fleet can do with this aircraft,” she offers. From Land to Sea With plans for the F-35 to fly in the diverse environmental homes of our international partners around world, testing of the aircraft is robust and covers every possible flight scenario. During her time at PAX, Brittany has had the opportunity to support three separate flight test detachments: the F-35B Developmental Test-2 (DT-2) aboard the USS Wasp, F-35B wet runway and crosswind testing at Edwards Air Force Base (AFB) and most recently, F-35B climatic testing at Eglin AFB. “Supporting these detachments is one of my favorite parts of the job,” she offers with a smile. “It helps me shake it up a bit and gain new, valuable experiences.” Brittany’s three-week detachment to the USS Wasp for the second F-35B sea trials was by far her most unforgettable experience as a flight test engineer. “Working aboard a carrier for three weeks was a once in-a-lifetime opportunity,” she reflects. ”Looking back on it now it almost feels unreal—we were standing on deck not far from the aircraft, watching short takeoffs (STOs) and vertical landings (VLs). I feel incredibly lucky to have had that experience.” Brittany has also had her fair share of supporting various program firsts from the control room. She helped monitor test points during the first weapons separation, first vertical takeoff (VTO) and the first VL at night, both on land and at sea. Never a Dull Moment Brittany never imagined that this was the sort of hands-on work she would be doing just a few years out of school. “This is not at all what I imagined I would be involved in,” she reveals. “I thought I would be at a desk all day, working on some type of analysis or design for some tiny part. That is certainly a far cry from the dynamic work I do on the aircraft every day now.” “Dynamic” it certainly is. On a daily basis, Brittany works on everything from supporting flight test in the control room, which includes participating in mission briefs and debriefs, monitoring safety of test parameters and completing post-test activities. She can even find herself troubleshooting a problem on the aircraft, coordinating maintenance and regression activities, updating information on the screens used to monitor the aircraft in the control room, assisting in test planning or supporting an event at the Manned Flight Simulator. “I actually enjoy not always knowing what the day will bring,” she says. Brittany and her team constantly rise to the challenge of the unknown. After all, the goal of testing is to see how the aircraft behaves under different conditions and parameters. Any time an unexpected jet behavior occurs, it is the team on-site who must implement a solution in real time—and this is why the work of Brittany, her fellow flight test engineers and truly the whole team is instrumental in the success of the F-35. For Brittany, it is not only the work that she does, but also the team that she is a part of that makes her experience in flight test so rewarding. “The team at PAX is an extraordinary team. We are fully capable of pulling together and overcoming the challenging obstacles we face in order to meet program milestones to the best of our abilities—it’s excellent.”

Le logiciel du F-35 C'est un sujet que j'ai déjà abordé et je voudrais en faire une synthèse dans une série de posts. Je commencerais avec l'introduction de l'article que j'ai publié dans 45enord.ca/ http://www.45enord.ca/2014/05/le-logiciel-du-f-35/ Un logiciel embarqué est, normalement, beaucoup plus léger, en taille, et beaucoup plus complexe à mettre au point qu'un logiciel de gestion classique. De plus il faut faire une ségrégation entre le logiciel "critique" et le logiciel normal car si, par exemple, le module "navigation" a une erreur fatale, il n’est pas envisageable que les commandes de vol ne répondent plus. Et il est bien évident que le logiciel critique demande plus de travail et de tests que le logiciel normal. Une première difficulté vient de l’impossibilité d’augmenter indéfiniment la taille des équipes logicielles. Ce point est illustré dans Les paradoxes de la productivité dans la production des logiciels de François Horn: "les mois et les hommes ne sont interchangeables que lorsqu’une tâche peut être divisée entre plusieurs travailleurs sans réclamer de communication entre eux" et "si n taches doivent être séparément coordonnées avec chaque autre tâche, l’effort augmente en n*(n-1)/2. Dans des situations extrêmes ces activités supplémentaires font plus que compenser l’apport de travailleurs supplémentaires". Pour contourner cette difficulté le même document donne une solution qui consiste à effectuer un important travail préalable au niveau de l’architecture du système pour le décomposer en modules plus petits qui doivent avoir une indépendance maximale de façon à limiter les activités supplémentaires de coordination entraîné par la décomposition. Cette introduction est là pour faire sentir que lorsqu'on a affaire à de gros logiciel complexes, on n'est pas libre du point de vue du planning, et on ne peut pas forcément diminuer le temps de développement en augmentant les ressources. A propos du logiciel du F-35 on n'a qu'une information : sa taille, pour évaluer le temps de développement il existe des modèles assez sophistiqués, mais qu'on ne pourra pas utiliser par manque d'information. Avec seulement la taille on ne pourra utiliser que le modèle COCOMO. Mais vous verrez que c'est mieux que rien!