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The Question & Answer (Q&A) Knowledge Managenet

The Internet has many places to ask questions about anything imaginable and find past answers on almost everything.

Table of Contents

- How do you calculate feet per minute in aviation?
- How do you calculate an aircraft climb rate?
- How do you convert nm to FPM?
- How many feet per minute do planes descend?
- What is the 3 1 rule in aviation?
- When should you start a descent?
- How do pilots know where they are?
- How long does it take for an airplane to reach cruising altitude?
- What do airport lights mean?
- What do the 4 lights on the runway mean?
- What are PAPI lights?
- What does a Papi look like?
- What are Vasi and PAPI lights?
- What is a papi FAA?
- Is Papi mandatory?
- What is the difference between Papi and Apapi?
- Can aircraft land without Papi?
- How do you remember PAPI lights?
- What does 4 red PAPI lights mean?
- What does Vasi mean?
- What is a slope indicator?
- What is my slope?
- How do you calculate the slope of a moving average?
- How do you trade a linear regression slope?

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).

Climb Rate Required:

- Formula: Ground Speed (GS) (knots) ÷ 60 * Climb Gradient (Feet Per Mile)
- Example: Ground Speed = 75 knots. Climb Gradient Required = 200 feet per mile.
- Calculate: 75 ÷ 60 * 200 = 280 feet per minute climb rate required.

Re: Converting feet/NM to FPM Here is the rule, for that speed you use a multiplier of 90/60 = 1.5. If you are curious, the units of that multiplier are nm/min, which explains the “trick”. So, 458 is the required climbout in fpm.

Idle descent in many jets is around 3,000 feet per minute until reaching 10,000 feet. There is a speed restriction of 250 knots below 10,000 feet, therefore the flight management computer will slow the aircraft to 250 knots and continue the descent at approximately 1,500 feet per minute.

In aviation, the rule of three or “3:1 rule of descent” is that 3 nautical miles (5.6 km) of travel should be allowed for every 1,000 feet (300 m) of descent.

As an example, if the airplane is flying at 30,000 feet the pilot should start the descent at 90 miles. Once the airplane is closer to the airport and the instrument landing system (ILS) can be used, the 3-degree descent is more finely tuned to touchdown.

Primarily, the “ILS,” as it is commonly known, consists of two radio beams emitted from transmitters right next to the runway. All pilots have to do is follow the beams down to 200 feet above the ground, at which point they must be able to see the runway and its approach lights.

10 minutes

The lights marking the ends of the runway emit red light toward the runway to indicate the end of runway to a departing aircraft and emit green outward from the runway end to indicate the threshold to landing aircraft.

Precision Approach Path Indicator

PAPI (precision approach path indicator) lights are a set of lights positioned beside the runway which provide pilots with a visual indicator of their aircraft’s position relative to the correct glidepath for the runway. Two of each shows the pilot is on the correct path for landing.

The PAPI is a light array positioned beside the runway. A PAPI can, if required, be located on the right-hand side of the runway. The red lights are always on the side closest to the runway. If the PAPI is on the right-hand side of the runway (non-standard), the red lights will be on the left.

A precision approach path indicator (PAPI) uses lights similar to the VASI system except they are installed as four lights in a single row, normally on the left side of the runway. An aircraft is on the appropriate glide path when two of the lights are red and two are white.

PAPI (Precision Approach Path Indicators) primarily assists by providing visual glide slope guidance in non-precision approaches environment. These systems have an effective visual range of at least 3 miles during the day and up to 20 miles at night.

The Indian regulations makes the PAPI a mandatory requirement for jet aircraft operations. Yet, airlines have been violating this mandatory safety requirement. It is wrong to call the operations into Goa as a “Blind landing”. They are unsafe landings without the mandatory visual aid.

The PAPI system allows the pilot to have the necessary visual information to place the aircraft on the ideal approach slope and can be used by day or night. APAPI system is used as PAPI system but it is composed of one wing bar formed by just two units.

According to the International Civil Aviation Organisation and the DGCA norms, jet aircraft like Boeing 737s and A320s should not operate from airports that do not have a functional PAPI.

Mnemonic to remember The array of lights is stationary, usually two or four light units on a single row, and the lower half of the light is behind a red filter and the top half a white filter. Their positions are calibrated to a 3-degree glideslope to the runway.

Whether you’re flying VFR or IFR, following the PAPI is a good idea. A series of 4 horizontal lights will show 2 red, 2 white when you’re flying on the established glide path (typically 3 degrees). The more red lights you see, the lower you are on glide path.

visual approach slope indicator

The Slope indicator measures the slope of a linear regression, which is the line of best fit for a data series. A 20-period Slope, therefore, measures the slope of a 20-day linear regression. In general, a positive slope indicates an uptrend, while a negative slope indicates a downtrend.

To find the slope, you divide the difference of the y-coordinates of 2 points on a line by the difference of the x-coordinates of those same 2 points.

The Moving Average Slope subtracts the moving average level n-periods ago from the current moving average level. For example, a recent magazine article referred to slope as the 80-day simple moving average of the daily closing price minus the level of the same 80-day simple moving average 10-days previous.

A linear regression trendline uses the least squares method to plot a straight line through prices so as to minimize the distances between the prices and the resulting trendline. This linear regression indicator plots the slope of the trendline value for each given data point.