Step climb


Step climb

A step climb in aviation is a series of altitude gains that improve fuel economy by moving into thinner air as an aircraft becomes lighter and becomes capable of faster, more economical flight.

Description

Since the early days of jet aircraft and commercial travel, the technique of gradually climbing in cruise altitude as fuel burns off and the aircraft becomes lighter has been widely used by pilots. The altitude that provides the most fuel-efficient cruise at the start of a long flight, when the aircraft is fully loaded with fuel, is not the same as the altitude that provides the best efficiency at the end of the flight, when most of the fuel aboard has been burned. This latter altitude is usually significantly higher than the former. By climbing gradually throughout the cruise phase of a flight, pilots can make the most economical use of their fuel.

Originally, a simple cruise climb was used by pilots. This amounted to a simple, continuous, very gradual climb from an initial cruise altitude to a final cruise altitude, and made the most efficient use of fuel. However, with increasing air traffic and the assignment of distinct flight levels to specific flights, airways, and directions of flight, it is no longer safe to climb continuously in this way, and so most flights compromise by climbing in distinct steps—a step climb—with ATC approval, in order to ensure that the aircraft is always at an appropriate altitude for traffic control. While not quite as efficient as a continuous cruise climb, step climbs are still more efficient than maintaining a single altitude throughout a flight. The step climb intervals may be 1000, 2000, or 4000 feet, depending on the flight level rules which apply on the particular airway being flown.

Where traffic is not an issue, cruise climbs may still be used. The Concorde, for example, used a continuous cruise climb throughout its flights, since there was never any other traffic at the same altitude (nearly 60,000 feet) in the same direction.

In most modern commercial airliners, computers such as flight management systems (FMS) calculate and/or execute the proper steps in a step climb, in order to maximize the efficiency realized by the technique.

Step and cruise climbs are not normally applicable to lower-flying aircraft propelled by conventional piston engines with propellers or turboprops, since their performance characteristics may be very different from those of Turbofan or Jet engined aircraft. In fact, the most efficient altitude for a small general-aviation aircraft may be only a few thousand feet above the ground, and increasing altitude may diminish efficiency rather than improve it.

Informal step climbs

Some pilots use "rules of thumb" for determining when to perform a step climb. These "rules" do not consider the effects of different winds at different levels; computerised flight planning systems may be better at height optimisation, and may even include 'step descents' in certain weather conditions. Two of the information rules used by some pilots are:

  • Keep climbing whenever you are light enough to climb to the next highest available flight level, until it is time for descent.
  • If it is possible to stay at the next higher cruise flight level for 20 minutes or more before "top of descent" (TOD) then it is cost-effective to make the climb.

See also


Wikimedia Foundation. 2010.

Look at other dictionaries:

  • Climb — For other uses, see Climbing (disambiguation) An Embraer ERJ 145 climbing In aviation, the term climb refers both to the actual operation of increasing the altitude of an aircraft and to the logical phase of a typical flight (often called the… …   Wikipedia

  • Climb Ev'ry Mountain — Single by Shirley Bassey from the album Shirley Bassey B side …   Wikipedia

  • climb — 01. The boys decided to [climb] the tree to steal some apples. 02. The baby was able to [climb] up onto the chair all by herself. 03. Sophie [climbed] up to the top of the rock face and then called down to the others to follow her. 04. If you put …   Grammatical examples in English

  • step — {{Roman}}I.{{/Roman}} noun 1 in walking, running, etc. ADJECTIVE ▪ large, small ▪ heavy, light ▪ quick, slow ▪ hesitant …   Collocations dictionary

  • step — I (New American Roget s College Thesaurus) n. pace, stride, footfall; footprint; gait, tread; stair, rung; interval, gradation; (pl.) measures, action. See degree, agency, nearness, travel. II (Roget s IV) n. 1. [A movement of the foot] Syn. pace …   English dictionary for students

  • climb — 1. verb 1) we climbed the hill Syn: ascend, mount, scale, scramble up, clamber up, shinny up; go up, walk up; conquer, gain Ant: descend 2) the plane climbed …   Thesaurus of popular words

  • climb down — (Roget s IV) v. Syn. step off, come down, dismount; see descend 1 …   English dictionary for students

  • climb down — go down, come down, step gradually down …   English contemporary dictionary

  • climb up — go up, come up, step gradually up …   English contemporary dictionary

  • Two steps forward one step back — For the book written by Lenin, see One Step Forward, Two Steps Back. Two steps forward one step back... is a catchphrase reflecting on an anecdote about a frog trying to climb out of a water well; for every two steps the frog climbs, it falls… …   Wikipedia


Share the article and excerpts

Direct link
Do a right-click on the link above
and select “Copy Link”

We are using cookies for the best presentation of our site. Continuing to use this site, you agree with this.