# What is the significance of the 10,600 lbs MTOW limit?

I recently noticed that several airplanes have MTOWs very near or exactly 10,600 lbs. That was an interesting phenomenon to me because I am familiar with the 12,500 lbs MTOW regulatory limit on certain types of small planes, and familiar with the 19,000 lbs MTOW regulatory limit on certain other "commuter" planes, but I couldn't find anything to support why so many airplanes would have MTOWs at 10,600 lbs.

As I tried to google for "10,600 lbs max takeoff limit" I found more planes that are at or very near that exact MTOW but couldn't find the basis for why this is.

Does it have to do with European regulations? Does it have to do with insurance considerations?

Airplanes with near or exactly 10,600 lbs MTOW

• Cessna CitationJet / M2
• Beechcraft King Air C90 / and derivatives
• Embraer Phenom 100
• HondaJet HA-420

I have noticed that 10,600 lbs is very close to 4,800 kg. So its possible that this regulation stems from something non-FAA, something that regulates in kg, but even still, I haven't had any more luck with Google trying to figure out what the derivation of a 4,800 kg limit might be. Yet again, all I found was yet more planes that have that same MTOW limit.

• It may have something to do with taxes, depreciation schedules and other ways to reduce taxes on the aircraft. I know some EASA countries have different taxes for aircraft above and below 17,000 MTOW. – wbeard52 Sep 12 '16 at 14:44
• I can't find the specific regulations now, but I believe there are differences in requirements and permitted operations for "Very Light Jets", which are set at/near that 10,600 lbs level. Very Light Jet (VLJ) is a comparable designation to the "Light Sport Aircraft" (LSA), although obviously at a different point on the scale – Jon Story Sep 12 '16 at 15:58
• Ive asked a friend who flies Citations if there is any significance to that figure. I'm not entirely sure its not just a coincidence – Jamiec Sep 12 '16 at 16:08
• @JonStory, from doing a little googling on your idea, it does seem like part of the conventional industry definition for a VLJ is "up to 10,000 lbs MTOW" however I didn't easily find any FAA regulations that would contribute to that limit nor any explanation as to why all of these planes would be so consistently over that limit by ~600 lbs. – Charles847 Sep 12 '16 at 16:18
• Remember it may not be an FAA (US) restriction, it could be one of many other CAA's - or it may be some kind of rating for certain runway types. On the other hand it could just be a convention based on the size/capacity/performance characteristics of these jets – Jon Story Sep 12 '16 at 16:20

It's nothing more than playing catch up.

If company X managed to build an aircraft for a certain mission at the lowest ever MTOW. Company Y will try to get down to that MTOW to be able to compete. Lowest is good if the mission is the same.

Check the MTOW of the Airbus A320-100 and the Boeing 737-400, to save you time, they are 200 pounds apart. But the A320-100 didn't sell well, the A320-200 did. Guess what, the 737-800 matched that weight.

## Here's why:

There's something called Weight Factor. $$\text{Weight Factor}=\sqrt{\frac{\text{(MTOW in kg)}}{5}}$$

The Weight Factor determines the route charges.

This charge takes into account the distance flown and, less than proportionately, the aircraft weight.

That's why it's vital for competitors to have similar MTOW's. So they can advertise similar operating costs. MTOW is also used in airport fees.

The only interesting thing about 10,600 lb / 4,800 kg is that the weight factor is kept a tad under 10.00 (two decimal places are used). Now, is there a higher charge for a plane with WF at or above 10? I scoured the internet, there doesn't seem to be WF brackets set that way, to my dismay.

Ryanair has part of their fleet tailor-made to an MTOW of 66,990 kg (WF ~36.60) for similar reasons apparently, or they're just being cheeky.

It's also why some airlines don't choose the Extended Range. The 777-200 airframe and its ER version are the same (no auxiliary fuel tanks).

The differences are extra certification for higher MTOW, and the same engines but certified for higher thrust. Airlines can request a conversion to ER if they open routes to farther destinations.

• I looked into weight factor but the 4800kg weight doesnt seem to have any significance. You need to be under 2000kg to be treated any differently. Obviously I still haven't solved this but I am skeptical of your answer. I doubt airframers are too concerned about the MTOW (by itself) of their competitors until they brush up against exactly the sort of regulatory or pricing constraints that I brought up. Certification rules, airport and traffic fees, insurance, etc. And on that wiki list of airplanes you linked, you'll notice that very few have the exact same weight to the pound as each other. – Charles847 Sep 13 '16 at 1:52
• @Charles847 If competitors have similar MTOW's. They can market similar operating charges for the same mission. – ymb1 Sep 13 '16 at 2:37