Aircraft Towing

[Maddog808]

Should an agricultural tractor be used for carrying out towing and ground positioning of general aviation aircraft? I am used to the tractors used in the commercial world so the sight of an agricultural tractor being used for this task is alien to myself. The correct tow bar is used however on the commencement of the tow the initial movement is more of a jolt rather than being smooth so the concern is this may place more of a strain on nose wheel components than a conventional towing/ tow bar-less tractor would. Anyone else had experience of this?

[Krystal n chips]

Should an agricultural tractor be used for carrying out towing and ground positioning of general aviation aircraft? I am used to the tractors used in the commercial world so the sight of an agricultural tractor being used for this task is alien to myself. The correct tow bar is used however on the commencement of the tow the initial movement is more of a jolt rather than being smooth so the concern is this may place more of a strain on nose wheel components than a conventional towing/ tow bar-less tractor would. Anyone else had experience of this?

Never towed GA aircraft, but I have towed glider winch cables with an agricultural tractor and something called the " weak link".....a few strands of old cable knotted together came in useful.....this may give you a clue.

Depends entirely on the a/c size / weight of course, but that little item called a tow bar shear pin will only take so many, or even one good, "jolt " before it works as advertised. It can be quite "entertaining " sat in a commercial aircraft when this happens.

So that little "jolt" may not only potentially damage the nose u/c, it may also damage the aircraft if you have nobody on the brakes....

Not forgetting the driver and their competency if more than one will be towing.

[Wodrick]

Just an opinion but an agricultural tractor is totally unsuitable for aircraft towing. I have done a lot in the past the smallest being 1-11s, irrelevant really.
Every tug I have ever used has had an automatic gearbox and has been designed for the purpose.
When you are dealing with aircraft the only way is properly.

[oldpax]

RAF used Davy Browns with weights on the running boards ,also a hydraulic gearbox which gave a smooth pull from standing.Most towing arms (heavy aircraft)had a overtorque link which would part under to much sudden acceleration(talking 1960s stuff now though!!

[cjhants]

I seem to remember British Midland having an agricultural type tractor at LHR in the eighties, which I am pretty sure they used on some of the lighter aircraft (although it's a long time ago and the memory is a bit fuzzy). I'm sure somebody from BM ramp can confirm this. Commercial aircraft bars have torque pins to prevent pulling\pushing damage, and axial pins to protect turning damage. The smaller GA bars I have seen do not have shear pins, but exec jets certainly do.
The bars have an eye secured by a pin on the tug, which obviously allows for some movement, but a good tug driver will push the pin against the front of the eye before applying power to give a smooth start to the push.

[Ex Maintainer]

Only ever towed light aeroplanes. The heaviest being a Wessex. We used anything from ordinary cars, land rovers, ordinary manual tractors, panel vans, and even once a proper tractor full of cement and no suspension, manual of course.

Never used an auto tow vehicle.

It all comes down to the driver. Gentle and careful is what it is about.

Having said that, at a recent local air show, i did see several people pulling and pushing a light plane out of and into the hanger by the prop. Made me cringe.

[Avtrician]

The major concern is not getting the aircraft moving, but having the weight and brakes capable of bringing the towed aircraft to a safe stop

[Mooncrest]

Some of the earliest towing vehicles I came across were made by Douglas and Massey Ferguson. As I recall they were essentially agricultural tractors with a large box-style cabin built on the chassis. The smallest aircraft they were used with were J31s, not much bigger or heavier than many GA twins and in many cases a good deal less than some twin jets (not to mention a lot less valuable). I don't recall any damage to tractor or aircraft and, in fact, our Massey Ferguson MF5 could comfortably manage a push back on a fully-laden 733.

The FBO at the airport where I work has for many years used a small, cabless tractor for towing aircraft, anything from a Cherokee to a Global Express so it doesn't seem to be an issue for them.

[wrenchalot]

It makes no difference what type of tow vehicle you're using as long as it's capable of pulling and stopping; in the old days they were mostly standard transmission; it's all in the driver's ability of easing off the clutch, then increasing throttle as required.
It is much more important to know the turning limits; this is where an experience driver comes in.
As to shear pins, most vendors tow bars have them, most if not all home made bars don't.
Shear pin P/N: AN427-4 or -5 depending in the size of the bar....