AIRCRAFT TOWING PROCEDURES AND PRECAUTIONS

TOWING :

Towing is necessary to enable the aircraft to be 

moved without engine power The procedure 

required will vary greatly dependent on the type 

of aircraft to be moved.

In the case of light aircraft  with a tail wheel a flexible

 towing bridle can be used and a steering arm 

attached to the tail wheel. The towing vehicle is

 used to pull the bride which has been attached to

strong points of the aircraft, these are usually located

 at the main undercarriage legs.

As the vehicle pulls the aircraft forward, the tail wheel

 steering arm is held to direct the aircraft,as the 

vehicle turns in the direction required, the bridle can

 ride round in the pulley. The turning circle is limited 

by the stop plates on the bridle. This method ensures

 that an even pull is maintained on both sides of the

 bridle.

The same method can be employed on light aircraft 

with a nose wheel by towing the aircraft backwards.

Light Aircraft can also be towed using a towing frame

 this is similar method to the bridle except the towing 

frame is rigid and so can be used to steer the aircraft

 as well as tow it.

On larger aircraft tractors or tug are used to tow the aircraft using a tow bar attached to the nose undercarriage, the tow bars used are parts of the aircraft's ground equipment, they incorporate a shock absorber system normally a large spring to avoid snatching movements being transmitted to the aircraft structure. The tow bar also incorporates a shear pin to prevent excessive loads occurring between the tractor and nose undercarriage.

 

 

GENERAL SAFETY PRECAUTIONS :

The following precautions must be observed when

 towing operations are in progress, reference must be made to the aircraft manual for specific instructions.

(a) Aircraft must not exceed walking pace while 

being towed (in closed area). 

(b) Oleo-leg and tyres must be correctly inflated 

prior to moving the aircraft, and sufficient brake

 pressure available for an emergency stop.

(c) Undercarriage ground locks must be fitted 

prior to towing 

(d) At night Aircraft navigation lights must be “ON” 

(e) By-pass pin or towing pin must be fitted before 

connecting the tow bar. 

(f) A person in charge with all other team members 

in his sight.

(g) Personnel must be stationed on the wing tip and 

tail to ensure clearance round obstacles.

(h) There must be a competent person occupying the 

pilot set to operate the aircraft brakes in case of 

emergency.

 

 

SOME POINTS TO NOTE :

(a) When manhandling light aircraft by pushing, 

do not push on flying control surfaces or other 

delicate parts such as fabric skin. The leading edges 

of the wing are normally strongest, so push the 

aircraft backwards.

(b) To avoid unnecessary stress to tyres and 

undercarriage the maximum turning angle should 

never be exceeded the manufacture’s maximum 

turning angle is normally painted on the side of the 

aircraft nose. Try to terminate towing by leaving the

aircraft in a straight line, this will prevent side loads 

remaining on the tyres when the aircraft comes to 

stop.

(c) Do not operate the aircraft brakes while the 

aircraft is being towed, allow the tractor or tug to 

keep the aircraft under control.

ABNORMAL EVENTS-LIGHTENING STRIKE

Lighting always has two or more attachments points (One entry and one exit) one the aircraft skin. Lighting moves back along the surface of the aircraft (swept stroke zone). This can cause a chain of scattered attachments points along a line in the direction of travel of the aircraft.Lighting hits some areas more frequently than others.

Aircraft Zoning :

The aircraft is divided into three zones related to the probability of lighting strike:

Zone 1 : Surfaces where there is high probability of initial lighting attachment entry or exit (leading edge, trailing edge, nose)

Zone 2 : Surfaces where there is high probability of a “swept stroke zone”. The lighting has its initial point of attachment in zone 1 and moves into zone 2.

Zone 3 : All zones of aircraft that are not zone 1 and zone 2, i.e. low probability of attachment of a lighting strike.

Effect Of Lightening :

There are two types of possible risks to aircraft:
1: Indirect effect
2: Direct effect

Indirect Effects :

Electromagnetic fields related to the lighting attachment can cause unwanted transient voltages and currents in the aircraft wiring systems. In some conditions (low intensity strike, high protection) the effect can be temporary and the system can operate correctly again after the strike.
In other conditions (low protection, no circuit protection devices) the damage can be permanent requiring L.R.U replacement.

Direct Effects :

1)    Pitting / melt through
2)    Magnetic forces
3)    Resistive Heating
4)    Acoustic shock wave

INSPECTION REQUIREMENTS:

 1)Aircraft are designed to keep the effects of lightning to a minimum and make sure it can continue its flight and land safely after a lightning attachment.

2)It is necessary to do a full inspection after a lightning strike to make an estimate of the damage and then to judge through MMEL aircrafts can continue to service or not.

INSPECTION PREPARATIONS:

 1) Before you start, you get information from the crew about the flight condition.
 
2) All events reported by the crew must be checked in addition/conjunction with this inspection
 
3) Take all safety precaution/safety devices are installed.
 
4) Extension of flight control surfaces (Flaps,slats,spoilers & speed brakes)

HEAVY LANDING INSPECTION

HEAVY LANDING INSPECTION

The structural stress induced by a landing depends not only upon the gross weight at the time but also upon the severity of impact.However,because of teh difficulty in estimating vertical velocity at the time of contact,it is hard to judge whether or not a landing has been sufficiently severe to cause structural damage.For this reason,a special inspection should be performed after a landing is made at a weight known to exceed the design landing weight or after a rough landing, even though the letter may have occurred when the aircraft did not exceed the design landing weight.

Wrinkled wing skin is the most easily detected sign  of an excessive load having been imposed during a landing. Another indication which can be detected easily is fuel leaks along riveted seams. Other possible locations of damage are spar webs, bulkheads, nacelle skin and attachments, firewall skin, and wing and fuselage stringers.

If none of these areas shows adverse effects, it is reasonable to assume that no serious damage has occurred. If damage is detected, a more extensive inspection and alignment check may be necessary.

EXAM TECHNIQUE

 EXAM TECHNIQUE

Exam Technique for EASA Part 66 multi-choice questions

Your chances of passing the CAA-approved exams can be greatly enhanced by the use of
“exam technique”. The following points should help you to improve your performance:

1. Read the questions carefully. Don't rush and make sure that you've understood the
question before you select one of the answers. This should go without saying but it
still catches people out!

2. Think it through. Not all questions are straightforward and some are downright
confusing! If you can't understand the question try to get inside the examiner's head
and ask yourself what the question is really about and what knowledge the question
is actually trying to test.

3. Have you used all the information given in the question? You might just have
overlooked a vital piece of information. Once again, this comes down to checking
that you have read the question carefully before attempting to arrive at an answer.

4. A few questions don't actually give you all the information that you need. There
might be something missing from the question that you might have to assume?
Questions of this type are not good practice but they DO exist. If you think that
something is missing from the question you might need to decide on what could be
reasonably assumed (for example, that temperature does not change or that the
supply voltage remains constant).

5. Don't make up your mind too quickly. If one of the answers looks obviously correct
take another look – the examiner will often provide you with an answer that might
look more inviting than the others but is actually incorrect.

6. Never guess an answer. Always try to reason out the correct answer. If this doesn't
work, try to eliminate one of the answers so it becomes a choice of two rather than
three potential answers. In many cases you should be able to select one answer
that is patently wrong.

7. A few questions may have more than one correct answer - it's just that one of the
answers is “more correct” than the others! If you think that more than one answer
could be right you need to ask yourself which of the answers is the one that the
examiner wants to see. For example, does one of the answers convey more
meaningful information than the other (potentially correct) answer(s)? If so, this is
the one to go for! (Once again this is rather bad practice and the examiner should
ideally provide one answer that is uniquely correct and two others that are patently
wrong).

8. Don't give up! However hard you find the questions remember that people do pass
these exams and only one or two questions correctly answered can make all the
difference between a pass and a fail.

Good luck with your exams!

GENERAL VISUAL INSPECTION

GENERAL VISUAL INSPECTION

GENERAL :

 Inspection are visual examinations and manual checks to determine the condition of an aircraft or component. An aircraft inspection can range form a casual walk around to a detailed inspection involving complete disassembly and the use of complex inspection aids.

It has been proven that regularly scheduled inspections and preventive maintenance assure airworthiness. Operating failures and malfunctions of equipment are appreciably reduced if excessive wear or minor defects are detected and corrected early. Aircraft operating under the flight-hour system are inspected when a specified number of flight hours are acquiring .These inspections safe your aircraft.

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Airframe and engine inspections may range from pre flight inspection to detailed inspections. The time intervals for the inspection periods vary with the models of aircraft involved and the types of operations being conducted. Components with stated hourly operating limits are normally replaced during the inspection that falls the nearest hourly limit. The airframe and engine manufacture’s instructions should be considered when establishing inspection schedule. 

REQUIRED INSPECTIONS :

Federal aviation regulations (FAR) provide inspection procedure and time limits to all the operator and monitor them it self. Depending generally type of operations in which they are in use. For the purpose of determining their overall condition. Some aircraft must be inspected at least once in a year, while inspection is required for others after each 100 hours of flight.

In order to determine the specific inspection requirements and rules for the performance of inspections, reference should be made.

Federal Aviation Regulation which prescribe the requirements for the inspection and maintenance of aircraft in different types of operations.

HANDLING OF AIRCRAFT COMPONENTS

HANDLING OF AIRCRAFT COMPONENTS

DEFECTIVE AIRCRAFT COMPONENT FROM STOCKROOMS :

 

An aircraft component shall be considered defective in following instances.

(*) Incomplete/inadequate documentation, information or component history.

(*) Item found or suspected to be damaged during handling.

(*) Item's rack life expired or shows signs of degradation/deterioration.

(*) CN / AD /mandatory modification accomplishment is required.

SYSTEM OF TAGS:

All aircraft component and material shall be properly identified by use of tags as per applicability.

LRU TRACKING TAG:

LRU Tracking tag shall be used for serviceable component released from a shop. The "Unserviceable" portion of LRU tracking tag shall be filled for each one-to-one replacement. LRU tracking tag shall be attached to defective aircraft component.

REPAIR TAG: 

Repair tag shall be generated for an aircraft component LRU, removed without substitution. Aircraft component found discrepant by stores Quality inspector shall be send for inspection / testing with repair tag.

SERVICEABLE TAG:

Serviceable Tag is used for a Serviceable aircraft component by the shop.An aircraft component is released by stores quality inspector with serviceable Tag (Certificate of inspection) along with the copy of vendor's appropriate release certificate.

FRACTIONAL WORK ORDER:

For all fractional tasks,not requiring a certificate of release to service,the Fractional work order shall be used. However completion of task shall be recorded through work accomplishment advice on the particular form.

Fractional work order, whenever raised, shall be referenced in relevant Aircraft repair order ARO/Technical Logbook / Component Work package by the originator.

IDENTIFICATION TAG:

Identification Tag shall be attached with serviceable Aircraft components that have been temporarily removed from an aircraft / aircraft component (NHA) either to gain access or for troubleshooting, fault isolation, etc. Such a component shall be installed back upon completion of the required task. The tag shall identify reason for temporary and shall be signed by Aircraft Engineer, removing such aircraft component.

SCRAP TAG:

Scrap Tag shall be attached to the defective aircraft component, recommended for rejection/scrap.