Modern navigation systems, which (strengthen version)

Question

Modern navigation systems, which are found in most of today’s commercial aircraft, are made with low-power circuitry, which is more susceptible to interference than the vacuum-tube circuitry found in older planes. During landing, navigation systems receive radio signals from the airport to guide the plane to the runway. Recently, one plane with low-power circuitry veered off course during landing, its dials dimming, when a passenger turned on a laptop computer. Clearly, modern aircraft navigation systems are being put at risk by the electronic devices that passengers carry on board, such as cassette players and laptop computers.

Which one of the following, if true, LEAST strengthens the argument above?

(A) After the laptop computer was turned off, the plane regained course and its navigation instruments and dials returned to normal.

(B) When in use all electronic devices emit electromagnetic radiation, which is known to interfere with circuitry.

(C) No problems with navigational equipment or instrument dials have been reported on flights with no passenger-owned electronic devices on board.

(D) Significant electromagnetic radiation from portable electronic devices can travel up to eight meters, and some passenger seats on modern aircraft are located within four meters of the navigation systems.

(E) Planes were first equipped with low-power circuitry at about the same time portable electronic devices became popular.

GmatKnightTutor · Answer

Hey, people. Let’s get into this! We’re essentially looking for something that doesn’t do a good job of strengthening the passage.

(A) After the laptop computer was turned off, the plane regained course and its navigation instruments and dials returned to normal.

Not what we’re looking for since this does a good job. If the plane’s navigation stuff returned to normal AFTER the laptop was turned off, that would lend support that electronic devices such as laptops could be doing something negative (i.e. when they’re taken onboard and turned on).

(B) When in use all electronic devices emit electromagnetic radiation, which is known to interfere with circuitry.

Nope. This provides a strong and precise explanation for how modern planes with low power circuitry (which is more vulnerable than vacuum-tube circuitry in older planes) could be negatively affected by electronic devices that passengers carry on board.

(C) No problems with navigational equipment or instrument dials have been reported on flights with no passenger-owned electronic devices on board.

Nope. If flights with zero passenger electronic devices have never reported problems with their navigational stuff, this would lend support that electronic devices are to blame when they do occur when onboard.

(D) Significant electromagnetic radiation from portable electronic devices can travel up to eight meters, and some passenger seats on modern aircraft are located within four meters of the navigation systems.

Not what we’re looking for. This strengthens the argument pretty well if we’re told that some passenger seats (and therefore electronic devices passengers may sit with) are close enough to cause significant electromagnetic radiation to the navigation systems of the plane.

(E) Planes were first equipped with low-power circuitry at about the same time portable electronic devices became popular.

This is the answer. Just because two things happened around the same time doesn’t necessarily confirm in a powerful way that electronic devices were to blame, for example, for what happened to the plane in the passage. Neither the passage nor this answer choice describe an ongoing pattern or a strong causational link or reason that blames electronic devices for issues with the navigational stuff.

AXECHILL · Answer

Why wouldn't the answer be C? The pilots and the crew members aboard wouldn't be considered as Passengers right? So the electronic devices could belong to the Pilot which could cause the intereference.

guddo · Answer

Modern navigation systems, which are found in most of today’s commercial aircraft, are made with low-power circuitry, which is more susceptible to interference than the vacuum-tube circuitry found in older planes. During landing, navigation systems receive radio signals from the airport to guide the plane to the runway. Recently, one plane with low-power circuitry veered off course during landing, its dials dimming, when a passenger turned on a laptop computer. Clearly, modern aircraft navigation systems are being put at risk by the electronic devices that passengers carry on board, such as cassette players and laptop computers. 
 
Which one of the following, if true, LEAST strengthens the argument above?

The argument claims that passenger electronic devices can interfere with modern aircraft navigation systems. Most answer choices strengthen by connecting passenger devices to electromagnetic interference or to actual navigation problems.  The least strengthening answer  is the one that gives only a loose timing coincidence, without showing that the devices caused  navigation risk .

(A) After the laptop computer was turned off, the plane regained course and its navigation instruments and dials returned to normal.

This strongly strengthens. If the problem stopped when the laptop was turned off, that supports the idea that the laptop caused the interference.

(B) When in use all electronic devices emit electromagnetic radiation, which is known to interfere with circuitry.

This strengthens. It gives a mechanism by which passenger electronic devices could interfere with navigation circuitry.

(C) No problems with navigational equipment or instrument dials have been reported on flights with no passenger-owned electronic devices on board.

This strengthens. It supports the connection between passenger devices and navigation problems.

(D) Significant electromagnetic radiation from portable electronic devices can travel up to eight meters, and some passenger seats on modern aircraft are located within four meters of the navigation systems.

This strengthens. It shows that radiation from passenger devices can physically reach navigation systems.

(E) Planes were first equipped with low-power circuitry at about the same time portable electronic devices became popular.

This least strengthens. The fact that two things became common around the same time does not show that passenger devices interfere with aircraft navigation systems. It gives only a timing coincidence, not evidence of causation.

Answer: (E)

guddo · Answer

C is not the answer because it still strengthens the argument.

Yes, pilots and crew are not passengers. But C says that when  passenger-owned electronic devices  were absent, no navigation or dial problems were reported.

That makes passenger devices look more suspicious, not less. If crew devices were the real cause, we might still expect problems on flights without passenger devices.

C does not prove the argument, but it supports it  somewhat . E is weaker because it gives only a timing coincidence.

Modern navigation systems, which (strengthen version)

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Modern navigation systems, which (strengthen version)

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