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Jan
13
2019

Rapid Deceleration or Rejected Takeoff…What’s the Difference?

Posted 5 years 105 days ago ago by Randy Rowles

While conducting an FAA Airline Transport Pilot (ATP) – Helicopter practical test, the applicant was given an emergency during the takeoff phase of flight. In lieu of conducting a Rejected Takeoff procedure, the applicant initiated a climb to 40’agl, maintained 40kts of airspeed, and announced the execution of a Quick Stop maneuver. When queried about the method by which the Rejected Takeoff was conducted, the applicant advised “that is how a Quick Stop is done”. Note: For the purpose of this article, Rapid Deceleration and Quick Stop will have the same meaning.

In terms of the ATP – Helicopter practical test, the method in which the applicant executed the required maneuver was Unsatisfactory. Why? Because there is difference between a Rapid Deceleration and a Rejected Takeoff. 

A Rapid Deceleration or Quick Stop is used to decelerate from forward flight to a hover. It is often used to abort takeoffs, to stop if something blocks the helicopter flightpath, or simply to terminate an air taxi maneuver. (FAA Helicopter Handbook Chapter 10) 

It appears this definition of the maneuver would support the applicant’s decision to execute a Rapid Deceleration as the appropriate action to stop the helicopter. However, during the Pre-flight Briefing portion of the practical exam, an overview was provided to the applicant of the profile of the exam flight. To avoid confusion, I always stipulate that any aborted takeoffs shall be handled as a Rejected Takeoff profile.

The difference between these maneuvers begins with the manner of execution of the maneuver itself. The Helicopter Flying Handbook [regarding conducting a Rapid Deceleration] states “After leveling off at an altitude between 25 and 40 feet, depending upon the manufacturer’s recommendations, accelerate to the desired entry speed, which is approximately 45 knots for most training helicopters”. This procedure places the aircraft inside the Height/Velocity Diagram for most helicopters based upon the stated combination of altitude and airspeed. In no case does this configuration represent a normal takeoff profile. This is a modified takeoff profile to accommodate this maneuver.

In contrast, the Rejected Takeoff procedure emphasizes that the pilot [abort] the takeoff. This is an immediate action. Continuing to climb and/or accelerate the aircraft into a better position further down the runway would be an Unsatisfactory response to this maneuver. 

Often, ATP – Helicopter applicants will seek out a flight instructor to aid in their preparation for the FAA Practical Test. Most instructor pilots within a helicopter flight school may have only trained pilot applicants up to the Commercial Pilot level. It is because of this they may not be familiar with the Rejected Takeoff procedure and testing requirement. Additionally, the differences in the FAA standard between the Rapid Deceleration and Rejected Takeoff may not be realized.

The purpose of the Rapid Deceleration is to gain the ability to slow the aircraft to a desired groundspeed through the coordinated use of all flight controls simultaneously. Its intended purpose is stability and coordination. A bi-product of this maneuver is the ability to stop quickly in the event of a situation requiring a Rejected Takeoff procedure. In other words, the Rapid Deceleration provides the foundational flying to enable a pilot to execute a Rejected Takeoff when needed.

It is important to recognize that the Rapid Deceleration is a Commercial Pilot PTS maneuver. The Rejected Takeoff is an Airline Transport Pilot PTS maneuver. It is up to the applicant to know the difference and execute the maneuver correctly when on an FAA practical exam. However, the unseen wire crossing your takeoff path does not care what level of pilot certificate you hold!   

About Randy: 
Randy Rowles has been a FAA pilot examiner for 20 years for all helicopter certificates and ratings. He holds a FAA Gold Seal Flight Instructor Certificate, NAFI Master Flight Instructor designation, and was the 2013 recipient of the HAI Flight Instructor of the Year Award. Rowles is the owner/president of Helicopter Institute.