Passage Reference: . When an aircraft starts to descend, passengers' stomachs sink, too. Over 40% of accidents happen during the relatively short time from the final approach to touch-down. Nevertheless, flying remains one of the safest ways to travel; even during approach and landing accidents are rare. For this, passengers must partly thank the Instrument Landing System (ILS), which was adopted by the International Civil Aviation Organization (ICAO) as a worldwide standard in 1949. Now a new standard is called for, to take advantage of advancing technology, but people cannot agree on which one.

Tips: For the first paragraph, expect a heading about introducing the topic or problem, not details.

Why the other options are wrong:

• The safest way to travel: The paragraph mentions safety, but only as background. The main point is about changing standards, not proving flying is safe. This is an example-as-main-idea trap.
• Tips For a smooth landing: There is no advice or tips for passengers or pilots. This is a context shift trap.

Key Vocabulary:

• standard = official system
• adopted = officially accepted

Question Focus: Main idea - basic explanation of the Instrument Landing System

Passage Reference: B. Any new system has to be very good. The ILS enables aircraft to land even when weather conditions allow the pilot to see only 75 metres (250 feet) ahead. Indeed, the ILS signals are sometimes fed directly into the flight computer so that an aircraft cian land itself. The ILS signals come from two radio transmitters on the ground, each of which uses a different frequency.

Why this is correct: The paragraph explains what the ILS does and how it operates, including visibility limits and radio signals. This clearly matches how the ILS works.

Tips: If a paragraph explains a system step by step, the heading usually starts with 'How'.

Why the other options are wrong:

• The two transmitters: Although transmitters are mentioned, the paragraph explains the whole system, not just that one detail. This is an example-as-main-idea trap.

Key Vocabulary:

• enable = make possible
• transmitter = radio signal sender

Question Focus: Main idea - detailed description of the two ILS transmitters

Passage Reference: C. The localizer transmitter is at the opposite end of the runway to the landing aircraft and sends out a beam centred along the runway: this shows the aircraft's ILS receiver whether the aircraft is too far to left or right. The 'glide-path' transmitter, which is close to the point where the aircraft will touch down, points a beam towards the incoming aircraft, angled up at three degrees: this tells the receiver whether the aircraft's descent is above or below the glide-path.

Why this is correct: The whole paragraph is about two specific transmitters and what each one does. This matches the heading perfectly.

Tips: If a paragraph lists two parts equally, avoid headings that mention only one.

Why the other options are wrong:

• The function of the localizer: Only half the paragraph is about the localizer. The rest is about the glide-path transmitter. This is a partial truth trap.

Key Vocabulary:

• beam = directed radio signal
• descent = going down

Question Focus: Main idea - weaknesses and limitations of the ILS

Passage Reference: h. D. Although the ILS has proved highly reliable, it has three significant defects. The most serious is reflection: signals can bounce off buildings and confuse the system. Even an aircraft that is taxiing or parked can cause problems. Second, some of the ILS frequencies are close to those used by FM-radio broadcasters who have been given permission to increase the power of their transmitters, which will interfere with ILS. The third problem is the lack of frequencies for airports that are relatively close together.

Why this is correct: The paragraph clearly lists three problems with the ILS. The entire focus is on weaknesses, not benefits.

Tips: Words like 'defects' or 'problems' usually signal a negative-focus heading.

Why the other options are wrong:

• ICAO & FAA — two conflicting bodies: No organizations are discussed here. This is a wrong section trap.

Key Vocabulary:

• defects = problems
• interfere = disturb

Question Focus: Main idea - explanation of the Microwave Landing System

Passage Reference: her. E. So in 1978 the ICAO chose the Microwave Landing System (MLS) to replace the old ILS. The MLS also uses two radio signals from similarly sited transmitters to guide down aircraft, but there the similarity ends. The MLS uses narrow beams at a much higher frequency, sweeping back and forth across the path of incoming flights. A receiver on an aircraft registers when the beams pass and works out its angle to the runway from the timing of the signals. The new system is significantly less susceptible to interference than the ILS. And because its signals fan out wider, aircraft can make long curving approaches. This sometimes helps controllers manage traffic.

Why this is correct: The paragraph explains how MLS operates and why it is better than ILS. This is clearly about the system's working method.

Tips: When a new system is introduced, expect a 'how it works' heading.

Why the other options are wrong:

• Troubled transition work: No problems with changeover are discussed yet. This is a time/tense trap.

Key Vocabulary:

• susceptible = easily affected
• curving approaches = non-straight landings

Question Focus: Main idea - problems during the change from ILS to MLS

Passage Reference: affic. F. Recognizing the complexity of organizing an orderly changeover which would affect thousands of airports and tens of thousands of aircraft, the ICAO set January 1' 1993 as a target for the MLS to take over. Airports around the world began to order and install MLS transmitters. However, in the early 1990s the smooth transition was thrown into chaos. America's Federal Aviation Administration (FAA) became increasingly convinced that the satellite Global Positioning System (GPS), which is owned and operated by America's Department of Defence, was a better option.

Why this is correct: This paragraph focuses on how the planned changeover did not go smoothly and became chaotic. That matches the idea of a troubled transition.

Tips: Look for emotional words like 'chaos' to spot problem-focused headings.

Why the other options are wrong:

• How the GPS works: GPS is mentioned, but not explained here. This is a context shift trap.

Key Vocabulary:

• transition = changeover
• chaos = complete disorder

Question Focus: Main idea - explanation and benefits of GPS

Passage Reference: option. G. This system allows anyone with a receiver to calculate his exact position from radio signals transmitted by a network of 24 satellites orbiting the globe. America's armed forces and increasing numbers of civilian sailors, pilots and walkers use it to navigate with great accuracy. 'Die system works well and has the bonus that many aircraft already carry GPS receivers to help them find their way from one airport to another. Successful trials have already taken place and the FAA expects to authorize GPS landings in conditions where pilots can see at least 550 metres ahead by the end of the decade. This covers the many American airports which have generally good weather.

Why this is correct: The paragraph explains what GPS is, how it works, and where it is useful. This directly matches the heading.

Tips: Technology explanation paragraphs usually define function first, then benefits.

Why the other options are wrong:

• ICAO & FAA — two conflicting bodies: No disagreement is discussed here. This is a wrong section trap.

Key Vocabulary:

• orbiting = moving around
• authorize = officially allow

Question Focus: Main idea - agreement reached between different sides

Passage Reference: d weather. H. All this convinced the Americans to abandon MLS last year, upsetting European aviation authorities, which were concerned that in a war the American military might close down civilian access to the GPS. Earlier this year, a special meeting of ICAO considered the conflict and came up with a compromise which keeps airports happy but will require aircraft to carry extra equipment. Airports which want to stick with ILS can do so. Those which support MLS can introduce it in place of ILS and those which want to use the GPS (or its Russian equivalent) are to be given time to bring their technology up to ICAO standards.

Why this is correct: The paragraph is about disagreement and then compromise between countries and systems. The word 'compromise' is even stated directly.

Tips: If the paragraph shows a solution after disagreement, choose a compromise heading.

Why the other options are wrong:

• ICAO & FAA — two conflicting bodies: Conflict is mentioned, but the focus is on the solution, not the conflict itself. This is a partial truth trap.

Key Vocabulary:

• abandon = give up
• equivalent = equal alternative

Question Focus: Main idea - one receiver that works with every landing system

Passage Reference: For people who hoped for a world standard this looks like a mess. One answer may be the multi-mode receiver. These devices, which are now being developed by avionics firms in Europe and America, will give a consistent ILS-type display on the flight deck whether they are receiving signals from ILS, MLS or GPS.

Why this is correct: The paragraph gives one answer to the mess: the multi-mode receiver. These devices work with signals from ILS, MLS or GPS, so they are the main idea.

Tips: Last paragraphs often give a solution. Look for words like 'One answer may be'.

Why the other options are wrong:

• The safest way to travel: Safety is in the first paragraph, not here. This is a wrong section trap.
• A new standard is needed: The paragraph mentions a world standard, but it describes a device, not a new standard. This is a partial truth trap.

Key Vocabulary:

• avionics = electronic equipment in aircraft
• consistent = always the same

General Tips:

• Read all headings first and underline 2-3 key words in each.
• Focus on the main idea of each paragraph, not one interesting detail.
• Headings usually follow paragraph order from top to bottom.
• If two headings seem possible, choose the one that covers more of the paragraph.
• Do not reuse a heading once it is matched.