Inspection of malfunctions and damages of the aircraft

 

National Aviation UniversityInstituteMaintenance Department






report

of malfunctions and damages of the aircraft







Done by: Oleksandr Krasnoshchok,Chelpanova, Stanislav Pashnyak: FLA-106by: L. Zhuravlova






2012


Content


Introduction1. Inspected damages

Our visual inspection of the aircrafts which are present in the hangar of NAU9

.1 Damages of a fuselage

.2 Damages of an engine

.3 Damages of a wing

.4 Damages of a tail unit

.5 Damages of a landing gear

Part 2. What to do while accident?

Emergency landings (on ground and on water)water landings

Conclusion



INTRODUCTION

are serious problem in aviation. Great amounts of damages cause improper operation of an aircraft or even to the catastrophes. The aircraft engineers have to carry out some technical maintenance to get rid of all the things which may cause the improper operation of an aircraft. Different types of operations are used to prevent damages formation.damages can be classified into different classes: dents, nicks, scratches, cracks, holes, abrasions, gouges, corrosions, notes, delamination, disbonds. Dent is depressed or hollow deformations without removal of material or change in cross sectional area. Generally dents are caused by impact from a smoothly contoured object. One characteristic that all dents should have is a "pushed in surface" and a relatively smooth bottom where metal is not displaced, folded or creased. Many Aircraft Structural Repair Manuals specify that a "crease" be treated as a crack. Generally when evaluating dents, the width of the dent is the second longest distance across the dent, measured at 90 degrees to the direction of the length.

Nicks are broken edges without cracks, but with portions of material removed. Negligible damage limits will vary with structure, material, and loading.

Scratches are marks penetrating the surface that reduce the structural cross section of the material but do not penetrate the complete thickness. The depth of a scratch may be determined by use of an optical micrometer. Generally, scratches in Alclad aluminum alloy sheet that do not penetrate the protective Alclad layer are classified as negligible.

Cracks are fractures that would not separate the material into two parts if the surrounding supports were removed; usually originating at edges, holes, or points where concentrated loads are applied or where abrupt changes in cross-sectional area occur. Cracks cause a significant cross-sectional area change. This damage usually has an irregular line and is often the result of fatigue in the material. The length of cracks that may be tolerated varies widely with material, structure, and application. No crack should be regarded as negligible until the damage limits for the affected structure have been determined

Holes are punctures, penetrations or cutouts that breach the complete thickness of the material and is fully surrounded by undamaged material. The size, shape, and distance from edges and supporting structures must be considered when evaluating hole damage.

Abrasion is a damaged area that is the result of scuffing, rubbing, scraping, or other surface erosion. This type of damage is usually rough and has an irregular shape.

Gouge is a damaged area where the result is a cross-sectional change caused by a sharp object and gives a continuous, sharp or smooth groove in the material

Corrosion is a deterioration of a metal because of an electrochemical reaction with its environment. Depending on the type of corrosion, this deterioration may take the form cracking, exfoliation, or erosion of the corroding material. Corrosion damage is typically classified as light, moderate, or severe, depending on the extent of the corrosion and the loading requirements of the corroded part. Aircraft-specific structural manuals should be consulted for the correct classification of corrosion damage on a given part.

Not: is an initial accurate determination of the type of damage encountered can usually be made by the use of a 10X magnifying glass or an optical micrometer. True crack length determination will generally require some form of Non Destructive Testing such as Eddy Current or Fluorescent penetrants.

Delamination is a separation of the layers of material in a laminate, either local or covering a wide area, that occurs during manufacturing or in service. Fiber-reinforced and composites may delaminate when impacted and not exhibit visible damage.

Disbond is an area within a bonded interface between two adherents in which an adhesion failure or separation has occurred. If the separation is performed deliberately to referred to as a debond.aviation accident is defined as an occurrence associated with the operation of an aircraft which takes place between the time any person boards the aircraft with the intention of flight until such time as all such persons have disembarked, in which a person is fatally or seriously injured, the aircraft sustains damage or structural failure or the aircraft is missing or is completely inaccessible. There are different types of aviation accidents: aircraft fires, accidents caused by an air traffic controller error, accidents caused by pilot, accidents involving controlled flight into terrain, aircraft collisions, accidents caused by fog or fuel exhaustion, runway incursionsý.

Aircraft maintenance checks are periodic inspections that have to be done on all commercial/civil aircraft <#"justify">Transit check

Transit check - is the simplest form of an aircraft maintenance. Its carried out before every flight.

Daily Check

Daily Check is the everyday check of aircraft performance. It must be done in every 24 hour (sometimes in every 36 hour). Usually this check is carried out at night.

Weekly Check

Weekly Check is done approximately once a week. It can be done at night and day as well. It doesnt require a special room (like hangar). Its carried out every 3-4 hours as usual.

A Check

This is performed approximately every 500 - 800 flight hours. It needs about 20 man-hours and is usually performed overnight at an airport gate. The actual occurrence of this check varies by aircraft type, the cycle count (takeoff and landing is considered an aircraft "cycle"), or the number of hours flown since the last check. The occurrence can be delayed by the airline if certain predetermined conditions are met.

B Check

This is performed approximately every 4-6 months. It needs about 150 man-hours and is usually performed within 1-3 days at an airport hangar. A similar occurrence schedule applies to the B check as to the A check. B checks may be incorporated into successive A checks, ie: A-1 through A-10 complete all the B check items.

C Check

This is performed approximately every 15-21 months or a specific amount of actual Flight Hours (FH) as defined by the manufacturer. This maintenance check is much more extensive than a B Check, as pretty much the whole aircraft is inspected. This check puts the aircraft out of service and until it is completed, the aircraft must not leave the maintenance site. It also requires more space than A and B Checks - usually a hangar at a maintenance base. The time needed to complete such a check is generally 1-2 weeks and the effort involved can require up to 6000 man-hours. The schedule of occurrence has many factors and components as has been described, and thus varies by aircraft category and type.

D Check

This is - by far - the most comprehensive and demanding check for an airplane. It is also known as a Heavy Maintenance Visit (HMV). This check occurs approximately every 5-6 years. It is a check that, more or less, takes the entire airplane apart for inspection and overhaul. Also, if required, the paint may need to be completely removed for further inspection on the fuselage metal skin. Such a check will usually demand around 40.000 man-hours and it can generally take up to 2 months to complete, depending on the aircraft and the number of technicians involved. It also requires the most space of all maintenance checks, and as such must be performed at a suitable maintenance base. Given the requirements of this check and the tremendous effort involved in it, it is also the most expensive maintenance check of all, with total costs for a single visit being well within the million-dollar range.

Because of the nature and the cost of such a check, most airlines - especially those with a large fleet - have to plan D Checks for their aircraft years in advance. Ofttimes, older aircraft being phased out of a particular airline's fleet are either stored or scrapped upon reaching their next D Check, due to the high costs involved in it in comparison to the aircraft's value. On average, a commercial aircraft undergoes 2-3 D Checks before it is retired. Many Maintenance, Repair and Overhaul <#"justify">As pilot in command you are responsible to ascertain that the aircraft is an airworthy condition. As such it is required to check all aircraft papers as weight (mass) and balance, aircraft logbooks, licenses and limitations. Part of any flight is a visual inspection of the aircraft.

Visual inspectioninspection is the most basic and common inspection method, and involves getting the inspector to "see" where one normally couldn't. This is done with the use of tools such as fiberscopes, borescopes, magnifying glasses and mirrors. Successful use of the technique requires good lighting and vision for best sensitivity, as well as training & experience which are vital for accurate interpretation of features.


Advantages of Visual Inspection

-Inspection performed rapidly and at low cost

-Ability to inspect complex sizes and shapes of any material

-Minimum part preparation required

Limitations of Visual Inspection

-Surface to be inspected must somehow be accessible to inspector or visual aids

-Surface finish, roughness and cleanliness can interfere with inspection

-Only surface defects are detectable

Visual inspection or walk around is done by the pilot or mechanic as final airworthiness check. In this section we describe were and what to look for when inspecting your aircraft. The walk around is a visual inspection for the general condition of the aircraft and it is intended to make a final check for its airworthiness. Especially important during the winter season, is to remove even small accumulations of frost, ice or snow from the wings, tail and control surfaces.are a number of items that need to be checked on the exterior of the aircraft during the walk around (this order can be slightly different but this one would work for any high wing aircraft like Cessna's, Murphy's or Pelicans):

·Cabin

·Empennage (French for the tail section)

·Right wing trailing edge, wingtip and leading edge

·Nose and Engine

·Left wing leading edge, wingtip and trailing edge

In the cabin it is needed to check for a number of items, most importantly are aircraft papers like: POH, Weight (mass) and Balance and insurance. At this point It is also checked the movement of the stick/yoke and listened for any odd sounds and check if elevator/ailerons move in the correct direction without problems. After making sure no one is standing near the propeller/engine switch on the master and check fuel level. While we are in the cabin: we check for any sign of mice or other rodent which may have turned the airplane into their house.leaving the cabin and walk, while looking at the fuselage for anything out of the ordinary (missing antenna's, dents, loose bolts, missing rivets, remove any bird droppings), towards the tail feathers (empennage).



PART 1. INSPECTED DAMAGES

visual inspection of the aircrafts which are present in the hangar of NAU

the result of our inspection of the aircrafts fuselages which are hold in the hangar of our university we have found massive scratches, damages of a skin, holes, absence of rivets, traces of corrosion and other different damages. They are shown in the following pictures:





On the figures 1-4 we can see the damages of a fiberglass window. The absence of some rivets is shown on the third picture. The traces of corrosion are shown on the fourth one.


.1 Damages of a fuselage

fuselage is the main structure in the aircraft that holds crew, passengers and cargo. An aircraft fuselage structure must be capable of withstanding many types of loads and stresses, and at the same time with low weight.damage is unexpected physical injury of an aircraft which can lead to depressurization, loss of power or improper work of an aircraft system and it is caused by external things, such as birds strike, watering (corrosion), faults of a crew or else.two most frequently types of structural damages in a fuselage are the longitudinal cracks due the pressurization cycles and the circumferential cracks due the bending and torsion of the fuselage. These damages can occur along all the shape of fuselage: in the nose, in the glass part, at the joints., monocoque, and the semi-monocoque solutions are found for the design of this structure. Truss or ramework types of construction have wood, steel or aluminum tube, or other cross sectional shapes which may be bolted, welded, bonded, pinned, riveted or machined into a rigid assembly.principal source of the stresses in this structure is the internal pressure in high altitude caused by difference of cabin pressurization and reduction of the outside pressure with increase in altitude, but the structure is subjected to other loads, as bending, torsion, thermal loads, etc.damages of a fuselage are represented in the following pictures. There are rupture holes in the nose of a fuselage, scratches, corrosion, and cracks.


5. Minor impact damage


6. Hole in the nose of a fuselage


7. Corrosion

8. Damage caused by hailstone

were some accidents involving the damages of a fuselage:

, August 22 - Far Eastern Air Transport Flight 103, a Boeing 737, disintegrates during flight and crashed near Taipei, Taiwan; severe corrosion in the fuselage structure leads to explosive decompression and disintegration at high altitude; all 110 on board are killed.

, July 13 - Southwest Airlines Flight 2294, a Boeing 737-300 from Nashville to Baltimore makes an emergency landing in Charleston, West Virginia after a 14x17 inch hole opens in the skin of the fuselage at 34,000 feet (10,000 m), causing a loss of cabin pressure; the plane lands safely with no injuries.

, April 1 - Southwest Airlines Flight 812, a Boeing 737, ruptures a hole in the fuselage at 36,000 feet, causing the cabin to lose pressure after takeoff from Phoenix Sky Harbor. The plane lands safely at Yuma International Airport, Arizona with all 118 people aboard uninjured.


.2 Damages of an engine


An engine is a machine <#"justify">Today's modern airplanes are powered by turbofan engines. These engines are quite reliable, providing years of trouble- free service. However, because of the rarity of turbofan engine malfunctions, and the limitations of simulating those malfunctions, many flight crews have felt unprepared to diagnose engine malfunctions that have occurred.turbo machinery in the engine uses energy stored chemically as fuel. The basic principle of the airplane turbine engine is identical to any and all engines that extract energy from chemical fuel. The basic 4 steps for any internal combustion engine are:

) Intake of air (and possibly fuel).

) Compression of the air (and possibly fuel).

) Combustion, where fuel is injected (if it was not drawn in with the intake air) and burned to convert the stored energy.

) Expansion and exhaust, where the converted energy is put to use.can be found some damages of the aircraft engine caused by overheating, birds strike, or other reasons.

Damages Caused by Overheating in Engines

220 Degrees

·When the engine reaches just above 220 degrees, combustion of the gasoline can occur in areas other than just in the combustion chamber; this is known as detonation. This detonation creates painful blows to the piston and can damage the piston, piston rings and even the connecting rod bearings. Detonation can damage spark plugs and create enough heat to actually melt down the ground strap of the spark plug.

250 Degrees

·If the engine reaches 250 degrees, all the rubber and plastic parts of the engine will begin to soften, which can pose a serious risk to engines with plastic intake manifolds, because they can crack or distort, losing their shape and creating vacuum leaks even after the engine has cooled. Hot spots will begin to develop inside the combustion chamber, causing pre-ignition, which can be so damaging it can even burn holes through the top of the piston and crack the ceramic insulator of any spark plug.

265 degrees and up

·At 265 degrees and above, the metal components of the engine, aluminum and cast iron will begin to soften and distort. When this type of distortion happens, the cylinder head will expand and can crush the head gaskets, creating an instantaneous mixture of engine oil and coolant. Even after the engine has cooled the cylinder heads will remain warped and will need to be replaced. The stress from this heat can cause any metal component of the engine to crack or become damaged beyond repair. The engine valves and pistons can begin to swell and scrap inside of their bores. In most cases of this type of extreme heating, the engine itself will generally seize and need to be replaced.

Effects of Extreme Heat on Coolant

·A 50/50 mixture of ethylene-glycol antifreeze and water can withstand temperatures of up to 265 degrees in a sealed system before it will boil. When engine coolant becomes this hot it can potentially produce holes and leaks in old coolant hoses. An aged radiator can burst and spew hot coolant in any and all directions. If coolant gets this hot and manages to work its way into the crank case, all of the bearings and seals for the crankshaft will be ruined.

Aircraft Damages Caused by Birds

Most of the bird strikes do not lead to any serious consequences and do not cause any significant damage to the aircraft itself. However in a small number of strikes engine or planner parts can be damaged, and in particular cases the strikes become an acute problem with a catastrophy character. to the data registered for the civil aviation aircrafts belonging to Russian air companies in 2002-05 the percentage of strikes in regard to different parts of the plane is the following.


One strike can involve up to several dozens of birds, which can cause damage to more than one part of the aircraft.


Figure 9. The impeller blade damages


10. Birds strike

maintenance of an engine requires a very proper exploration. The vibration in the engine must be checked.the visual inspection of the aircraft engines we did not notice any damages. But if this inspection was more precise I think this damage could have been found.


.3 Damages of a wing

wing is a principal structural unit of an airplane. Its function is to lift and to support the airplane during the flight.maintain its all-important aerodynamic shape, a wing must be designed and built to hold its shape even under extreme stress. Basically, the wing is a framework composed chiefly of spars, ribs, and (possibly) stringers (see figure 1-5). Spars are the main members of the wing. They extend lengthwise of the wing (crosswise of the fuselage). All the load carried by the wing is ultimately taken by the spars. In flight, the force of the air acts against the skin. From the skin, this force is transmitted to the ribs and then to the spars.wing structures have two spars, the front spar and the rear spar. The front spar is found near the leading edge while the rear spar is about two-thirds the distance to the trailing edge. Depending on the design of the flight loads, some of the all-metal wings have as many as five spars. In addition to the main spars, there is a short structural member which is called an aileron spar.ribs are the parts of a wing which support the covering and provide the airfoil shape. These ribs are called forming ribs and their primary purpose is to provide shape. Some may have an additional purpose of bearing flight stress, and these are called compression ribs.damages of a wing are different: damaged ribs or bulkheads, broken fastening, broken parts of trailing (or leading) edge.


Figure 11. The rear of the slate is de-laminating Figure


. Broken leading edge


In our hangar there were some airplanes with broken parts of wings. Particularly, there were troubles with the skin on the wings. Some of airplanes even did not have a skin cover at all.


.4 Damages of a tail unit


The empennage also known as the tail or tail assembly, of most aircraft gives stability to the aircraft, in a similar way to the feathers on an arrow. Most aircraft feature empennage incorporating vertical and horizontal stabilising surfaces which stabilise the flight dynamics <#"justify">The aircraft's cockpit voice recorder and flight data recorder are often located in the empennage, because the aft of the aircraft provides better protection for these in most aircraft crashes.


13. Damaged tail unit

the investigation of aircrafts in our hangar we have found some damages in the tail assemblies. You can see that damages in the following pictures:



14-15. Damaged tail assembly

the damages of tail unit we can find problems with fin, elevator, trimmers, and rudder. These problems are caused by external factors.

damage aircraft accident landing


1.5 Damages of a landing gear

undercarriage or landing gear is the structure that supports an aircraft on the ground and allows it to taxi, takeoff and land. Typically wheels are used, but skids, skis, floats or a combination of these and other elements can be deployed, depending on the surface. Gear arrangementstaildragger arrangement was common during the early propeller era, as it allows more room for propeller clearance. Most modern aircraft have tricycle undercarriages. Taildraggers are considered harder to land and take off (because the arrangement is unstable, that is, a small deviation from straight-line travel is naturally amplified by the greater drag of the mainwheel which has moved farther away from the plane's centre of gravity due to the deviation), and usually require special pilot training. Sometimes a small tail wheel or skid is added to aircraft with tricycle undercarriage, in case of tail strikes during take-off. The Concorde, for instance, had a retractable tail "bumper" wheel, as delta winged aircraft need a high angle when taking off. The Boeing 727 also had a retractable tail bumper. Some aircraft with retractable conventional landing gear have a fixed tailwheel, which generates minimal drag (since most of the airflow past the tailwheel has been blanketed by the fuselage) and even improves yaw stability in some cases.gear may have such damages as wear, holes, cracks, scratches and others. In the following picture you can see the landing gear damages of the aircraft of National Aviation University hangar:



Each of the aircraft's four main landing gear wheels has electrohydraulic disc brakes and an anti-skid system.

Part 2. What to do while accident?

majority of those involved in plane crashes survive. Here are some ideas for increasing odds of making it through such an event. A plane crash is a terrifying experience, and the very idea is enough to make many people avoid flying altogether. Although much of what's happening will probably be beyond your control, there are a number of things people can do to increase their chances of survival. Here are some guidelines.the plane takes off, count the rows between you and the emergency exits in case power failures or smoke reduce your visibility. Keep your seat belt on when you're sitting, and don't wander around unnecessarily. Put your tray up when you don't need it. The procedures followed during an inflight crisis vary widely depending upon the situation. Follow the directions given by the airline staff - they've been trained for these events. If it's obvious that there will be a crash, put your head between your knees or against the seat. If you have a pillow or a blanket, put it on your lap. The theory here is that if you're going to be thrown forward anyway, you'll reduce possible injuries by assuming that position beforehand. Breathe slowly and deeply and think about where the nearest emergency exit is located.impact, you will hopefully be able to unbuckle yourself and move toward the exit. This is a crucial time. Many airplane crash deaths and injuries occur not because of the actual crash but because of the fire that erupts afterward. Don't try to bring your carry-on luggage. Stay low, but don't crawl or you could be trampled. Watch the floor lights; those near emergency exits will be red. Go through the exit one person at a time.a typical plane, you'll slide down an inflatable ramp after exiting. These are very strong, so don't be afraid of punctures. Help at the bottom in whatever way you can. A flight attendant may ask you to help people off the ramp. If not, consider joining those already off and moving them as far from the plane as possible. Look for injured people and assist them. Comfort those who are panicked, especially children. If possible, look for a place to call 911.planes crash in remote areas. This compounds fear and confusion. Try to find or make a clear space away from the wreckage for people to rest and get their bearings. Emotional trauma can be just as exhausting as physical injuries, so don't expect people to be up and ready to move. In this situation, think about the most basic human needs before trying to find help. Assuming you've done what you can for the injured, your first priority is to find clean water. With that taken care of you can focus on getting help, finding food, creating shelter, and salvaging what you can from the wreck.matter what happens, stay calm. Remembering this statistic might help: almost 60% of people involved in airplane crashes survive. Following these tips will increase those odds even more.

landings (on ground and on water)

emergency landing is a landing made by an aircraft in response to a crisis which either interferes with the operation of the aircraft or involves sudden medical emergencies necessitating diversion to the nearest airport. There are several different types of emergency landings for powered aircraft: planned landing or unplanned landinglanding - the aircraft is forced to make a landing due to technical problems, or in rare situations with light aircraft, weather conditions. Landing as soon as possible is a priority, no matter where, since a major system failure has occurred or is imminent. This means that the forced landing may even occur when the aircraft is still flyable, in order to prevent a crash or ditching situation.landing may result from a planned landing at a location about which information is limited, from unanticipated changes during the flight, or from abnormal or even emergency situations. This may be as a result of problems with the aircraft, or a medical or police emergency. The sooner a pilot locates and inspects a potential landing site, the less the chance of additional limitations being imposed by worsening aircraft conditions, deteriorating weather, or other factors.landing is caused by the failure of or damage to vital systems such as engines, hydraulics, or landing gear, and so a landing must be attempted where a runway is needed but none is available. The pilot is essentially trying to get the aircraft on the ground in a way which minimizes the possibility of injury or death to the people aboard.is the same as a forced landing, only on water. After the disabled aircraft makes contact with the surface of the water, the aircraft will most likely sink if it is not designed to float, although it may well float for hours, depending on damage.


Emergency water landings


US Airways Flight 1549 after ditching in the Hudson River

passenger and cargo aircraft and helicopter ditchings have been documented. These intentional emergency water landings are the result of an in-flight fuel depletion or mechanical malfunction and not an accidental overshoot of a runway or an uncontrolled crash into a body of water.

The FAA <#"justify">Conclusion

are different types of damages. And those damages prevent the proper work of an aircraft. The consequences can be different. It can be a loss of power, depressurization or even worse, up to the breaking of an airplane part.the result of our practice we have learnt how to carry out visual inspection, how to conclude the report of condition for each aircraft and how to work with different types of damages.inspection of aircraft damages is the one of very important parts of the work of the Aircraft Engineer. So, this practice gave us some knowledge which is to be used by us when we go to a job.the next generations, we would advice to be careful during transit visual inspections. Our carefulness will lead us to the safety flights.



References


1.Testing, inspection, maintenance and storage procedures <http://www.globalsecurity.org/military/library/policy/army/accp/al0993/le4.htm>

.Maintenance and Certification - Torque Paint (Slippage Marks) <http://www.tc.gc.ca/eng/civilaviation/publications/tp185-3-05-paint-3861.htm>

.Composite materials for aircraft structures Alan A. Baker, Stuart Dutton, Donald W. Kelly

.Air Worthiness: An Introduction to Aircraft Certification Fillip De Florio

.<http://en.wikipedia.org>

.<http://civilavia.info>

.<http://www.ehow.com/info_12203115_damages-caused-overheating-engines.html>


National Aviation UniversityInstituteMaintenance Department report of malfunctions and damages of the aircraft

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