How to tow airplanes
• How to tow airplanes
Towing aircraft - a process which in one way or another affects many participants (drivers, technicians or mechanics, towing crew, dispatchers, airline representative.
He also has a lot of nuances - both organizational and technical. I'll tell you about towing mainly in terms of materiel device.
Airplanes and Boeing-737Classic -NG regarding towing differ slightly, so the story will be further illustrated by photos of how to order, and the other type. Basic value generation aircraft here will not have. I remind you that many of the photos have the option of larger size, which can be viewed in detail, if you click on the picture shown in the post.
Tow plane is needed in different cases. For example, when domestic and international flights in Pulkovo were distributed between terminals 1 and 2, often mark the arrival of the apron of the terminal and departure - from the other platform. Sometimes, airplane comes and will stand for a long time - for example, a great form of MOT. In this case a long time to hold a convenient parking lot (for example, apron) do not give, and the plane should be cleaned.
Moving the aircraft on the airfield normally carried out by towing by a tractor.
Haul aircraft as may be necessary, for example, when the circuit with the band on the slimy ground. In this case, towing cables made for the main landing gear. If we talk only about the regular towing with less effort, they made tractors for the front foot. In foreign ports are common trucks coming off the front foot of the aircraft from the surface of hydraulic hoist, and moving the plane of that leg. In our ports of tractors almost gone. Because they need a very smooth and clean the platform, that in Russia, you know ... So usually towed aircraft on a rigid hitch - carrier, clinging to the front foot. During towing sure there is someone on the plane. The process is called "sit on the brakes." The man in the cab is not for pokatushek. He - the last link in the security chain. He alone can stop the aircraft, if that.
The man on the brake applies the brakes in case of:
1. The decoupling of the tractor and the aircraft.
2. The danger of a collision with an obstacle.
3. The head of the team towing.
To begin with a look at the cabin. In the part related to towing, we see the following:
Exactly near the landing gear handle emergency accumulator is a pressure gauge (737 Classic):
737 NG priborchik also present, only slightly higher:
The accumulator contains a fluid under pressure, which is enough for several full braking cycles. It can be applied in the absence of any other source of hydraulic fluid pressure. Inflate the pressure in it from the hydraulic system B. On the ground, this means that it is necessary to incorporate an electric pumping station system B (by the way, the brakes also work cleanly on the system B).
From A system controlled by turning the wheels front legs. Therefore, before towing the better disconnect the hydraulic system. Not to break the carrier reaction force.
The parking brake is pulling out the metal flag near Rudov.
Of course, the red LED indicates the set parking brake.
Braked wheels separately - the left and right main landing - pressing feet on top of the pedal.
Just put the parking brake - Press the top of the pedal, pull box, release the pedal.
To release the parking simply press and release the brake.
And, perhaps, the last thing we need to learn in the cockpit - is communication.
on the audio device control panel (center console) includes a microphone button FLT (Flight Interphone). FLT push knob to hear towing head, connect the headset to the cabin. And Speaker, to enable broadcast through speakers or a headset to wear. It is also possible to communicate by radio or visual. Now, Let's go out. If the aircraft is towed in a crash, but simply rearranged or something, safety pins (pins) are inserted into the retraction mechanisms to foot accidentally developed.
, and the main ones:
These pins do not give legs to withdraw from the lock released position, even if the cab to pull the chassis for cleaning during hydraulic systems included.
The front leg 737 NG.
The cap protects the No Step kinematics control reversal feet. From there, in the cabin are a turn control cables - just to the left of the captain WHEEL (for turning large-angle). Well, he can still pedal taxi, but only for small angles. Two pieces of wheels - Turning hydraulic cylinders. Work on the hydraulic system A. To while towing the system to turn off to the right, we see the handle.
When her turn looped cavity cylinders. At the time of the towing handle is fixed Ping:
(to connect the carrier)
After towing aircraft for departure towing disconnects the carrier, pulls the pin and typically, parting from the crew, it shows.
If the pin is not removed, the plane will not rulitsya.
In conventional towing rotation angle of the wheels front legs should be no more than 78 degrees. This limit is displayed to the driver of the tractor, and other interested parties a red stripe on the wings of the front wheel wells:
The angle of 78 degrees is limited slot-hinged rear legs and posting on it (to rulozhnoy spotlight).
If disunite slot-hinge and release the wiring plane can roll in tight spaces (hangar, for example).
The tractor is connected to the aircraft via the carrier - the transverse bolt on the front leg below rulozhnoy lights:
A typical aircraft carrier in:
This is - quite a good option, with the carrier is convenient to operate. In principle, the carrier consists of several parts: a metal pipe, wheels with lifting device, eye for grasping the carrier to the towing vehicle and head for engagement to the aircraft. Ear for connecting to the towing vehicle:
Nothing special. Two brackets welded to the pipe - to capture the carrier arms. Heavy.
Wheels with lifting device:
There is already becoming a little more interesting.
Wheels mounted on an axle. The carrier of this axis can be shifted along it - for the convenience of engaging the bolt on the front leg of the aircraft. To lift the wheel (so they while towing is not dragged along the platform) uses two pulling springs. To lower the wheels (when transporting carrier) swing handle hydraulic hoist. Hydraulic fluid is injected into the cavity of the hydraulic cylinder, its stem extends, and the wheels are lowered. To raise the wheels, it is necessary to open the valve on the side of the jack:
Then under the influence of the spring rod will be pushed into the cylinder, displacing the liquid in the tank. Before lowering the wheel valve must be closed again.
The head of the carrier:
The handle mechanism is fixed in the lower position "a dog" and that does not allow to open a cross-pin (male) with a ball lock.
To protect against damage to the front legs and the carrier in excess rotation force or a pulling force applied shear bolts (outlined in blue):
Empty the hole next because they are intended for installation of bolts to towing other aircraft type. This has led both to 737Classic and 737 NG. A connector size of a foot of these types are the same.
If you open the spring-loaded "dog" and lift the handle, we see the seizure, which led clings to the foot of the aircraft:
So, turn off the pin set.
The carrier injected into engagement grip for the bolt and the leg of the aircraft is raised up.
Bolt is in captivity, and the top fixed focus (folding handles)
The carrier is geared.
"dog" fix by opening Ping. This design has led the most prevalent today. Here, for example, the company has led to Boeing-767:
The same, only bigger (as the nearest - led to 737). As you can see, spare shear bolts are fixed to the carrier pipe. Because it is important to replace them quickly (for example, on the taxiing from the strip).
But this has led to the head 737 is not very easy to operate.
Such a carrier when unhitching aspires upwards and often strikes the body rulozhnoy lights 737.
But we digress. Customized tractor and cling to the carrier. This is usually done after stripping the ramp to move the aircraft when engaged not damage the door or something else.
opening the tap on a lift carrier lift wheels.
Remove the blocks from under the wheels of the aircraft. Communications cab give the command to withdraw the parking brake. Give the go-ahead to the driver of the tractor; it communicates with the dispatcher taxi.