Airport Hangars And

Aircraft Maintenance Operations

Minor Project Report

Submitted in partial fulfillment of the requirements for the award

of the degree of

Bachelor of Technology

In Aerospace Engineering

AMITY UNIVERSITY DUBAI

(2012-2016)

Submitted to: Submitted by:

Mr. Sarath Raj Michael Bseliss Lecturer Faculty A40105513001 Amity University Dubai Semester 6 / 3rd. Year

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BONAFIDE CERTIFICATE

This is to certify that Michael Bseliss, a student of B.Tech in Aerospace Engineering

Department has carried out the work presented in this report entitled “Airport

Hangars and Aircraft Maintenance Operations” as a part of 2015 year

programme of Bachelor of Technology in Aerospace Engineering from Amity

University, Dubai - UAE under my supervision.

Name of Faculty Guide: Signature of Faculty Guide:

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ACKNOWLEDGEMENT

I thank my faculty guide Mr. Sarath Raj for his full support, help and guidance.

I acknowledge his advice and suggestions that have helped me to make this report a

productive one.

I express our gratitude towards my parents for their complete motivation, support

and help in completing this term paper successfully.

I proudly dedicate my success in preparing this project to my country Syria, and my

lovely city Aleppo and hope that it will be fine soon

Lastly, I acknowledge every faculty and all my friends at Amity University, who have

been gracious in providing me with the required suggestion and help in every

possible way.

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Certificate 1

Acknowledgement 2

Introduction 5

Airport Hangars History 8

Hangars Types 10

3.1 Cargolifter Hangar 11

3.2 Tee Hangars 12

3.3 Bellman Hangar 13

3.4 Bessonneau Hangar 14

3.5 Blister Hangar 15

3.6 Underground Hangars 16

Aircraft Maintenance Operations 17

4.1 Inspection Types 18

4.2 Aircraft Maintenance Checks 19

4.3 MRO Operations 22

4

-All New- Hangars 23

Amity International Airport Hangars 28

Conclusion 30

References 32

5

An airport is an aerodrome with facilities for commercial aviation flights to take off and

land. Airports usually have facilities to maintain and store planes, and a air traffic control

tower. [1] An airport consists of adjacent utility buildings like control towers, terminals

and hangars as well as a landing area, that comprises an aerially accessible open space

including at least one operationally active surface such as a runway for an aircraft to take

off or a helipad. [2] Fixed base operator services, air traffic control centers, airport

aprons, passenger facilities such as lounges and restaurants, and emergency services may

exist in larger airports.

The Federal Aviation Administration or the FAA is an agency of the United States'

government which controls Aviation. This agency mandates identification standards for

airport layout which is meant to help pilots in recognizing runways from the air easily

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and to safely taxi from the runway to the gate. [3] From painted stripes & runway

numbers to runway lights and signs & airport.

Airports and aircrafts have evolved and continue to evolve. Airplanes began in the 1950-s

to have a variety of uses for transportation & business. Instead off tail skids, aircrafts

were equipped with steerable tail wheels to operate more easily on the ground.

As airplanes became larger and heavier heavier and larger it was important for airports to

have hard surface runways [3] instead of grass or gravel fields because such fields

couldn’t support the weight of heavy airplanes. (Boeing 747 at takeoff can weigh more

than 800,000 pounds). Eventually airports started to offer more services for airplane

operators & their increasing number of passengers.

A modern large airport today has thousands of workers, accommodates tens of thousands

of passengers, and loads or unloads hundreds of thousands of pounds of baggage and

cargo daily.

There are many types of airports that exist today as part of the United States' air

transportation system. [2] These airports range from a single grass airstrip in a rural area

or an agricultural to the large airports which serve major cities.

There are seven basic types of airports:

Rural airstrip.

Private airport.

Military airports.

Major city airport.

Small community airport.

Regional airport.

Regional community airport.

The differences one from the other depends upon the types of services it provides, [1] the

length of the runways with its complementary terminal facilities, the size aircraft it

serves, and its proximity to a densely populated area.

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Airports usually consist of many buildings and units, the main parts of airport are:

1) Passenger terminal buildings.

2) Control towers.

3) Airport Hangars and aircraft maintenance buildings.

4) Fire & Safety stations.

5) Fuel Tanks.

The airport model made by Aerospace Engineering students contains the above

mentioned parts, where this report will discuss the Airport Hangars part as well as the

maintenance operations which is done in the airport.

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A hangar is a closed building structure to hold airplanes in protective storage. Usually

hangars are built of metal, [4] but other materials such as concrete & wood may also be

used.

Hangars are used for: Protection from direct sunlight, protection from the weather,

manufacture, maintenance, repair, assembly & storage of aircraft on airfields, aircraft

carriers & ships.

During the early 20th century, Carl Richard Nyberg used a hangar to store his Flugan

(fly). [4] Louis Bleriot in 1909 crash-landed on a northern French farm in Les Baraques

(b/n Calais & Calais) then rolled his monoplane into the farmer's cattle pen. [4]

Meanwhile, Bleriot was in a race to be the first man to cross the English Channel in a

heavier-than-air aircraft, so he set up his headquarters in the unused shed.

The Wright brothers stored & repaired their airplane in a hangar [4] made by wood

constructed in 1902 at Kill Devil Hills in North Carolina for their glider.

The earliest airplane hangars were known as airplane sheds in Britain.

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Before World War 1 when aviation became established in Britain, standard designs of

hangar gradually appeared with military types [4] also such as the side-opening airplane

shed of 1913 and the Bessonneau hangar - both of which were later adopted by the Royal

Flying Corps.

The largest hangars ever built were those for airships, such as Hangar One (Mountain

View, California) measuring 1,133x308x198 feet, [4] as well as Goodyear Airdock

measuring 1,175x325x211 feet.

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Special structures are necessary to build a hangar. The width of doors should be large, the

aircraft entrance included. [5] Large airplanes need complex structure. Sizes can be

classified as follows according to the span of the hangar:

Size Span (meters)

S Less than 30 m

M 30–60 m

L 60–90 m

XL 90–120 m

XXL More than 120 m

For the largest aircraft in the world XXL hangars are built, for example:[5] the Airbus

A380, Antonov 225 and Boeing 747. Such structures are the most complex to erect.

Airship hangars (also known as "airship sheds") are generally bigger than normal aircraft

hangars, especially in terms of height. Early airships used hydrogen gas to provide them

with enough buoyancy for

flight, hence their hangars had

to provide protection from stray

sparks to prevent the flammable

gas from exploding. Hangars

that held [5] multiple vehicles

of this type were at risk from

chain-reaction explosions. So

most hangars for hydrogen-

based airships were built to house only one or two such craft.

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1) Cargolifter Hangar:

It is a hangar for production and operation of the CL160 & engineering team facilities

were built at Brand-Briesen Airfield on the former Soviet Air Force base, [5] acquired to

enable development and operations.

This hangar (360 m long, 220 m wide and 106 m high), is a freestanding steel-dome

"barrel-bowl" structure big enough to fit the Eiffel Tower on its side. It was equipped also

with a cutting table {180 m} to manufacture the envelope of airship.

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2) Tee Hangars:

It is a type of enclosed structure designed to hold aircraft in protective storage. Primarily

used for private aircraft at general aviation airports. [5] It is usually constructed of metal;

since this type of hangars is more economical than normal rectangular hangars, they are

used for private airplane at general aviation airports. There are two types of Tee hangars:

standard (sometimes called stacked) & nested.

Standard Tee Hangars:

Provide additional storage area & can use

rolling doors. [5] In this figure, the odd-

shaped areas at the end of the hangar clusters

may be omitted, or may be included as part

of the end hangars, or may be used as

segregated storage, shop or office space.

Nested Tee Hangars:

Require less building material than standard

and are wider, but shorter, thereby reducing

the length of taxiway required to abut the building. [5] The disadvantage is that rolling

doors cannot be used.

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3) Bellman Hangar:

It is temporary hangar was designed in 1936 in the United Kingdom by N. S. Bellman

Directorate of Works structural engineer, [6] as a temporary hangar capable of being built

or dismantled by unskilled labor with simple equipment and to be transportable easily. [6]

By November 1938, 10 had even been supplied to Russia.

Its general dimensions were 175 ft long, 95 ft wide (87 ft 9in clear width) and 25 ft (clear

height). It was constructed in 14 bays at 12 ft 6in centres based on a unit system of rolled

steel sections; both walls and roof used the same standard units joined at the junction of

wall and roof by a standard corner unit.

The time taken for 12 men to erect the hangar at Thornaby, including levelling the

ground, laying door tracks, erecting the steelwork, [6] and fitting oiled canvas doors was

500 man-hours.

Two light jib derricks

using timber poles

were required to erect

the fabricated [6]

vertical and side

members. The roof

trusses were assembled on the ground before being lifted into position.

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4) Bessonneau Hangar:

The Bessonneau [7] hangar was a portable timber and canvas aircraft hangar used by the

British Royal Flying Corps during World War I.

In about 1908, [7] the Bessonneau hangar was designed and manufactured by the French

rope and canvas manufacturer Etablissements Bessonneau, in 1910 specifically employed

to protect aircraft participating in a race from Angers to Saumur in France.

The hangar was supplied as a kit of parts that could be easily erected, dismantled,

transported and re-erected at another location. The principal material of the framework

was wood, joined by wooden plates, steel brackets and steel bolts. [7] Vertical stanchions

supported roof trusses, with extensively triangulated ties and beams. Bays (units) of

stanchions and trusses were built up and connected to each other, with each hangar

assembled with 6, 9 or 12 bays to achieve different hangar lengths. [7] Wooden flying

buttresses were applied to the sides and rear, to ensure rigidity, and ropes were used to tie

down the whole structure onto steel pickets driven into the ground. Snow poles were

attached to the underside of selected trusses, and hinged to allow them to be lowered for

extra roof support in the event of heavy snow or high winds. [7] The tailored canvas

covering was tied to the framework with ropes.

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The most common variant in Britain was the 6-bay design, providing inside clear

dimensions of width (span) 20 metres (65 ft 6 in), length 24 metres (79 ft) and height 4

metres (13 ft 2 in). [7] Outside dimensions were width 22 metres (72 ft), length 28 metres

(91 ft 10 in), height 7.7 metres (25 ft 5 in), excluding picketing ropes.

5) Blister Hangar:

A blister hangar is a novel arched, portable aircraft hangar designed by notable British

airport architect Graham R Dawbarn patented by Miskins and Sons in 1939. Originally

made of wooden ribs clad with profiled steel sheets, [5] steel lattice ribs and corrugated

steel sheet cladding later became the norm. It does not require a foundation slab and can

be anchored to the ground with iron stakes. Numerous examples were manufactured for

military use in World War 2 and various different sizes were available. Many found post-

war use as agricultural or industrial buildings and some still remain in use on airfields

such as Fairoaks, Redhill and White Waltham today.

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6) Underground Hangars:

An underground hangar is a type of hangar for military aircraft, usually dug into the side

of a mountain for protection. [8] It is bigger and more protected than a hardened aircraft

shelter (HAS).

An underground hangar complex may include tunnels containing the normal elements of

a military airbase - fuel storage, [8] weapon storage, rooms for maintaining the aircraft

systems, a communications centre, briefing rooms, kitchen, dining rooms, sleeping areas

and generators for electrical power.

Countries that have used underground hangars include Albania, China, India, Pakistan,

Italy, North Korea, Norway, South Africa, Sweden, Switzerland, Taiwan, Vietnam and

Yugoslavia.

The Indian Air Force operates underground hangars. Sukhoi Su-30 MKI have been

stationed at Trishul Air-base situated in Bareilly, [8] Uttar Pradesh, India. It houses one

of the largest underground hangars in Asia. Adampur, situated in Punjab, houses an air-

base with underground hangars. It is the home base for MiG-29.

17

Overhaul, is a common term or concept used in aviation industry, refers to the operations

of airplanes’ examination to make the required changes.

Aircraft maintenance is defined as the inspection, [9] overhaul and repair or modification

of airplane and/or its component.

Maintenance includes the removal or installation of a component from an aircraft or

aircraft subassembly, but doesn’t involve:

• Primary work, like removing & replacing tires, inspection plates, spark plugs,

checking cylinder compression etc. [9] on small privately operated aircraft ; or

removal and replacement of fuses, light bulbs etc., on transport category aircraft .

• Servicing, such as refueling, washing windows.

• Any work done on an aircraft or aircraft component as part of the manufacturing

process, prior to issue of a certificate of airworthiness or other certification

document.

Aircraft maintenance is highly regulated. [9] There are various airworthiness authorities

around the world. The major airworthiness authorities include:

Agência Nacional de Aviação Civil (ANAC) Brazil

Civil Aviation Administration of China (CAAC) China

Civil Aviation Authority (United Kingdom) (CAA)

Civil Aviation Safety Authority (CASA) Australia

Directorate General of Civil Aviation (India) (DGCA) India

European Aviation Safety Agency (EASA) Europe

Federal Aviation Administration (FAA) United States

Transport Canada (TC) Canada

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Although maintenance requirements vary for different types of aircraft, experience shows

that most aircraft need some type of preventive maintenance every 25 hours or less of

flying time, and minor maintenance at least every 100 hours. This is influenced by the

kind of operation, climatic conditions, storage facilities, age, and construction of the

aircraft. [9] Maintenance manuals are available from aircraft manufacturers or

commercial vendors with revisions for maintaining your aircraft.

Inspection Types:

Annual Inspection: Any reciprocating-engine powered or single-engine

turbojet/turbo propeller powered small aircraft (12,500 pounds and under) flown

for business or pleasure is required to be inspected at least annually [9] by an

FAA certificated A&P mechanic holding an Inspection Authorization (IA), or an

FAA certificated repair station that is appropriately rated, or the manufacturer of

the aircraft. [9] The aircraft may not be operated unless the annual inspection has

been performed within the preceding 12 calendar months. A period of 12 calendar

months extends from any day of a month to the last day of the same month the

following year. However, an aircraft with the annual inspection overdue may be

operated under a special flight permit issued by the FAA for the purpose of flying

the aircraft to a location where the annual inspection can be performed.

100 Hour Inspection: Reciprocating-engine powered and single-engine-

turboprop/turbojet powered aircraft (12,500 pounds and under) used to carry

passengers for hire or used for flight instruction, shall be inspected within each

100 hours of time in [9] service by an FAA certificated A&P mechanic, an FAA

certificated repair station that is appropriately rated, or the aircraft manufacturer.

An annual inspection is acceptable as a 100-hour inspection, [9] but the reverse is

not true.

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Other Inspection Programs: The annual and 100-hour inspection requirements

do not apply to large (over 12,500 pounds) airplanes, [9] turbojet, or

turbopropeller-powered multiengine airplanes.

Preflight Inspection: The FAR's require a pilot to conduct a thorough preflight

inspection before every flight to ensure that the aircraft is safe for flight.

Aircraft Maintenance Checks:

Aircraft maintenance checks are periodic inspections that have to be done on all

commercial/civil aircraft after a certain amount of time or usage; [10] military aircraft

normally follow specific maintenance programs which may or may not be similar to

those of commercial/civil operators. Airlines and other commercial operators of large or

turbine-powered aircraft follow a continuous inspection program approved by

airworthiness authorities.

Airlines and airworthiness authorities casually refer to the detailed inspections as

"checks", [10] commonly one of the following: A check, B check, C check, or D check.

A and B checks are lighter checks, while C and D are considered heavier checks.

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A check

This is performed approximately every 250 flight hours or 200–300 cycles. It needs

about 20–50 man-hours and is usually performed overnight at an airport gate. The

actual occurrence of this check varies by aircraft type, [10] the cycle count (takeoff &

landing is considered an airplane "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 6 months. It needs about 120-150 man-hours,

depending on the aircraft, and is usually completed within 1–3 days at an airport

hangar. [11] A similar occurrence schedule applies to the B check as to the A check.

However, B checks may also be incorporated into successive A checks, i.e.: Checks

A-1 through A-10 complete all the B check items.

C check

This is performed approximately every 20–24 months or a specific amount of actual

flight hours (FH) or as defined by the manufacturer. [10] This maintenance check is

much more extensive than a B

check, requiring a large

majority of the aircraft's

components to be inspected.

This check puts the aircraft

out of service and until it is

completed, the aircraft must

not leave the maintenance

site. [11] It also requires

more space than A and B

checks. It is, therefore,

usually carried out in 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 6,000 man-

hours. The schedule of occurrence has many factors and components as has been

described, and thus varies by aircraft category and type.

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D check

This is by far the most comprehensive and demanding check for an airplane. [12] It is

also known as a "heavy maintenance visit" (HMV). This check occurs approximately

every 6 years. [12] 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 can usually demand up to

50,000 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 elevated requirements of this check and the tremendous effort involved in it, it

is also by far the most expensive maintenance check of all, [12] with total costs for a

single visit ending up 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. Often, 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 comparison to the aircraft's

value. On average, a commercial aircraft undergoes 2–3 D checks before being retired.

22

Given the time requirements of this check, many airlines also use the opportunity in order

to make major cabin modifications on the aircraft, which would otherwise require an

amount of time that would have to put the aircraft out of service without the need for an

inspection. [12] This may include new seats, entertainment systems, carpeting, etc.

- MRO Operations:

MRO, maintenance, repair & overhaul involves fixing any sort of mechanical, plumbing

or electrical device should it become out of order or broken (known as repair,

unscheduled, or casualty maintenance). [13] It also includes performing routine actions

which keep the device in working order (known as scheduled maintenance) or prevents

trouble from arising (preventive maintenance). MRO may be defined as, "All actions

which have the objective of retaining or restoring an item in or to a state in which it can

perform its required function. [13] The actions include the combination of all technical

and corresponding administrative, managerial, and supervision actions."

23

Nowadays, a new concept is being developed about hangars, it is called inflatable hangar.

It’s a hangar made of special type of plastic textile, considered as portable hangar, can be

used for many types and sizes of aircrafts, with high features and properties.

The Solar-Impulse 2, solar powered aircraft which is performing a tour around the world

starting from Abu Dhabi is using this type of hangars in each airport where it lands.

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25

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27

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In our prototype airport model, scaled 1:1500, we have included three hangars: Two for

commercial aircrafts and one for private jets.

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30

The Future – Clear Span Hangars 2km long by 100m wide?

One of the most important requirements for a large aircraft hangar is that it should have

the widest possible door opening so as to be able to accommodate the biggest aircraft

flying or a mixture of many types, large or small, whose comings and goings will not be

restricted by widths of door openings, or by having to maneuver past other aircraft.

After many years research we have now designed a hangar whose clear doorway opening

can be the entire width of the hangar, whatever its span. For instance, an entrance could

be 100 meters or 500 meters or more without intermediate support columns. This is

achieved with a special steel structure and frontal lattice beam. This design places the

highest part of the hangar just where it needs to be – at the front – to accommodate the

tail section inside the hangar, without the need for a special tailgate door.

The electrically controlled individually operated doors roll on bottom rails. At the top,

vertical rollers operate within precision made guide channels, so that any single door or

number of doors can be moved to any part of the ground track and if necessary onto

outriggers. The design allows large areas of workshop and office space at the rear inside

the hangar, where the wings do not intrude. Foundations are reduced to a minimum.

As aircraft become increasingly advanced, researchers like those at Purdue's Hangar of

the Future Research Laboratory are exploring what the future of maintenance looks like.

The small group of faculty, students and research partners are examining everything from

the design of aircraft hangars to automating aspects of the maintenance process.

“If we take a look at maintenance operations and some of the NextGen and some of the

advancements in technology, our maintenance operation has probably not kept up scope-

wise. So, what are some of the things that Hangar of the Future could take a look at?”

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says Tim Ropp, a Purdue professor and one of the lead faculty members for the Hangar

of the Future project.

A hangar's design can affect productivity and communication channels, when upper-level

management is kept separate from workers, communication between the shop floor and

the management offices may slow down. Furthermore, hangars can be updated with

simple elements to help workers do their jobs better. We still see a few technicians

working with miner's lights, how can we design a hangar with more light? It's a small

detail, but it gets at what Hangar of the Future is all about: Rethinking maintenance

operations without the constraints of today's technology and infrastructure.

=============

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[1] virtualskies.arc.nasa.gov/airport_design/

[2] www.merriam-webster.com/dictionary/airport

[3] Wragg, D.; Historical dictionary of aviation, History Press 2008

[4] Building the Navy's Bases in World War II, History of the Bureau of Yards and

Docks and the Civil Engineer Corps, 1940-1946 Volume I - Part II: The Continental

Bases

[5] Cargolifter: Cargolifter-Boeing agreement". Retrieved 11 July 2006.

[6] Bellman: World War II Hangars -Guide to Hangar Identification Technical Bulletin

02/02, Defence Estates, Ministry of Defence UK, 2002

[7] Bessonneau Hangar: Histoire du Bessonneau

[8] "Underground Hangars to Protect War Planes" Popular Mechanics, September 1937

[9] "Canadian Aviation Regulations 2008-1, Part V - Airworthiness, Standard 593

Airworthiness Directives". Retrieved 9 December 2012

[10] Air Transport Association

[11] Federal Aviation Administration

[12] Description of a D-check at Aerosphere

[13] European Federation of National Maintenance Societies

============= The End