External winglets may have been forbidden - and homologated fairings made compulsory - for MotoGP in 2017, but that is not to say aerodynamic development will cease once the season has begun, race director Mike Webb has confirmed.

On the contrary, the 2017 rules have been written so as to allow each of the series' six manufacturers to alter the internal contents of any external ducts - like those seen at the preseason tests in Malaysia and Australia - meaning development, in all likelihood, will continue, albeit in a restricted capacity.

The decision to ban aerodynamic winglets from this season came mid-way through 2016, with MotoGP race direction citing safety concerns over carbon fibre sprouting out of fairings in 'unnatural' places. What's more, a limit on excessive spending on this area was sought.

However, as was highlighted in a piece on Motomatters.com last week, the rulebook focuses on limiting the development of the 'external shape' of the fairing, a feature that must be homologated before the season opener in Qatar.

The FIM Grand Prix regulations state that "Only the external shape, excluding the windscreen, is defined in this regulation, so the following parts are not considered as part of the Aero Body: windscreen, cooling ducts, fairing supports, and any other parts inside the external profile of the bodywork."

As Webb verified, it is what is 'inside the external profile' - "brackets, holders, vents" - that can then be modified, depending on the specifications of each circuit layout.

"It's specifically in the description of the homologated fairing that's in the rulebook now," Webb told Crash.net. "It says we're looking at the outside shape of the fairing, the outside profile.

"Anything internal including brackets, holders, vents, things like that, they don't follow under the homologation. Whatever - winglets, ducts - they put inside is free. They can do what they want. That's the area you'll see some development during the year. They will play with internal things but the external shape is fixed."

A host of innovative fairings have been on display at the two preseason tests, with Yamaha unveiling their prototype - an external addition to the fairing which housed internal winglets - on the second day at Sepang.

Aprilia and Suzuki soon followed suit, displaying a revised aerodynamic package on day two at the Phillip Island test. Ducati, Honda and KTM are yet to show their hands, with many anticipating something fairly radical from the Bologna factory.

Webb told Crash.net the ruling on whether a fairing complies with the rules is somewhat "subjective", with the final decision falling on the shoulders of Dorna's technical director Danny Aldridge.

"Basically he [Aldridge] has got the right of refusal because it's almost impossible to write a technical definition of what is and isn't," said Webb. "A general definition that he's following is that the external shape of the fairing has to be more or less a traditional motorcycle fairing.

"What he's looking for is a smooth contour on the outside. It can be wider than it was in the past because the rules allow up to 600mm wide. Most of the bikes weren't that wide. So they can make them wider. It's completely up to them but the outside contour has to be smooth, without things sticking out in points.

"By making the limit wider and putting the wings inside, it's completely legal. It also addresses our safety concerns about things sticking out of the bike. So that's fine. It's really up to him to rule on the shape.

"How radical, how sharply curved the outside can be before it's not deemed to be a traditionally smooth fairing. There has been some things submitted that have not been approved because they are clearly don't have a cover on them, as opposed to a wider fairing with stuff going on inside. So it's a bit subjective. It's up to Danny."

With one homologation coming before the first race on March, 26th, just one other upgrade can be introduced. Factories will then be permitted to alternate between the two homologations as they please (KTM, as a new manufacturer, is exempt from this rule).

"Whatever they start the season with, they can have one upgrade too whenever they want during the year," said Webb. "But that's it. Two for the season so that there is limited development, to try and keep a lid on it.

"Before we get to the first GP they have to decide on what they're going to start the season with. And [they will] probably have an idea in the back of their heads about what their next upgrade is going to be.

"So you'll see a few different things now and in Doha. At the technical control for the Doha GP they have to say, 'This is our starting point for the year.'"