# How do pilots know how fast to descend?

Question: How do pilots know when to descend to land on the assigned runway at the correct speed? Answer: Pilots plan the descent based on the wind and air traffic flow. Working in partnership with air traffic control, the descent is executed allowing adequate distance to descend and line up with the proper runway.

## How do you calculate descent speed?

If you multiply your descent angle (1 degree) by your miles-per-minute, then add two zeros to the end (x 100), you'll have your FPM descent rate. So in this example, if you're flying at 120 knots, you're traveling 2 miles-per-minute (MPM) (120/60=2).

## What is the 3 1 rule for descent?

A general rule of thumb for initial IFR descent planning in jets is the 3 to 1 formula. This means that it takes 3 NM to descend 1,000 feet. If an airplane is at FL 310 and the approach gate or initial approach fix is at 6,000 feet, the initial descent requirement equals 25,000 feet (31,000–6,000).

## Why does an aircraft descend quicker when it is lighter?

The lighter the machine is loaded, the less assistance is derived from weight at any given angle of descent, resulting in a lower rate of descent. Of course, at a 90 angle of descent—an exciting prospect—all of the weight of the aircraft would be acting as though it were thrust.

## Why do heavier riders descend faster?

Heavier riders can descend faster than light riders because heavier riders don't have significantly more volume/surface area than their lighter counterparts, despite possibly major differences in weight.

## What speed does 747 descend at?

This means you should begin your descent 105 nautical miles from your destination, maintaining a speed of 250 KIAS (about 45 percent N1) and a descent rate of 1,500 to 2,000 feet per minute, with thrust set at idle.

## How fast is an emergency descent?

It depends on the altitude the plane was flying at when the depressurization occurred. Airliners can descend over 8,000 feet per minutes if needed. A descent from 35,000 feet at that rate would have you down to 11,000 feet in 3 minutes or less.

## What is the maximum acceptable descent rate?

Follow A 1,000 FPM Descent Rate Limit

Operational experience and research have shown that a descent rate of greater than approximately 1,000 FPM is unacceptable during the final stages of an approach (below 1,000 feet AGL).

## What is a good rate of descent?

“500 feet per minute is a good rate to work with. Generally, passengers will not be alarmed by a decent rate of 500 ft/min. Pressure changes will occur slowly in an unpressurized aircraft. Also, keep in mind that ATC will expect a minimum rate of 500 ft/min on an IFR flight plan unless you advised them otherwise.

## How far away do planes start descending?

Commercial planes will typically fly at around 30,000 to 43,000 feet in the air. As the pilots begin preparing for landing, they'll typically descend to an altitude of around 10,000 feet before truly descending towards the airport.

## How far out do you begin your descent?

Start descent at three times your altitude (in thousands of feet) to achieve a 3 degree descent. If you are at 45,000 feet, for example, round the altitude up to 50, just to make things easy, and start down at 3 x 50 = 150 miles out.

## How do planes slow down on descent?

Slowing down is generally accomplished by reducing power and/or increasing pitch. Spoilers can be used in combination with increased pitch to slow down without climbing (particularly in the situation that the engine(s) are already at flight idle and can't be reduced further.)

## Can you feel a plane descending?

Answer: The sensation of slowing down is really one of slowing the rate of acceleration; this is due to reducing the thrust after takeoff to the climb setting. The sensation of “dropping” comes from the retraction of the flaps and slats. The rate of climb is reduced, causing it to feel like a descent.

## Can pilots forget to lower landing?

We were on about a half-mile final when I realized that the pilot had forgotten to lower the landing gear — and I'd forgotten to check. The low groundspeed and turbulence resulting from the strong low-level winds conspired to make airplane performance appear as if the gear was down. It can happen to anyone.

## Do pilots slow down in turbulence?

For moderate or extreme turbulence, pilots are trained to slow the aircraft down to the appropriate “maneuvering speed” for the aircraft's current weight. This protects the aircraft in that if it encounters extreme turbulence, the aircraft wings will essentially “stall” before the aircraft is damaged.

## What is the 1 2 3 rule in aviation?

You need to name an alternate airport on your IFR flight plan if, for the period of time one hour before and one hour after your estimated time of arrival, the weather is forecast to include a ceiling of 2,000 feet agl and/or visibilities less than three statute miles (the 1-2-3 rule).

## What is the descent rule?

In aviation, the rule of three or "3:1 rule of descent" is a rule of thumb that 3 nautical miles (5.6 km) of travel should be allowed for every 1,000 feet (300 m) of descent. For example, a descent from flight level 350 would require approximately 35x3=105 nautical miles.

## What is the normal descent rate of a 737?

This means you should begin your descent 105 nautical miles from your destination, maintaining a speed of 250 KIAS (about 45 percent N1) and a descent rate of 1,500 to 2,000 feet per minute, with thrust set at idle.

## What are the 5 C's in aviation?

Five C's:
• Circle: If able, you want to minimize your travel so you can orient to the location without anything changing and not get any further off track.
• Confess: Admit that you are lost and need some form of assistance. ...
• Climb: "Climb to cope" ...
• Conserve: ...
• Communicate: ...
• Comply:

## What happens if a plane loses cabin pressure?

Effects. Crew Incapacitation. Depending on the altitude of the aircraft when depressurisation takes place, loss of pressurisation can very quickly lead to the incapacitation of the crew and passengers unless they receive supplementary oxygen.

## What happens if a plane descends to fast?

If you try to land a plane too fast, it will immediately take off again. It is called porpoising and there is nothing the pilot can do about it - it is a matter of physics.

## Why do planes speed up before landing?

As the plane descends into ground effect, it may actually accelerate if the engines are producing enough thrust, since in ground effect the plane requires much less power to keep "flying". Power from the engines will translate into speed, if not height.

## Do planes still break the sound barrier?

Flying faster than sound

Supersonic flight was first achieved in 1947 with a US military prototype Bell X-1 aircraft. It has since become common in military aircraft, but only the two commercial aircraft mentioned above have ever managed it.

## Can a 747 hit Mach 1?

"Original flight tests of 747s conducted in 1969 and 1970 took 747-100 models to speeds of Mach 0.99. In addition, Boeing knows one case in which a 747 operated by Evergreen International made an emergency descent at speeds that exceeded Mach 1."