Rejected Takeoff

V1 is the speed selected for each takeoff, based on approved performance data and specified conditions. It represents:

1. The maximum speed by which a rejected takeoff assures a safe stop within the remaining runway or runway and stopway
2. The minimum speed which assures the takeoff can be safely completed within the remaining runway, or runway and clearway, after failure of the most critical engine at the designated speed
3. The single speed that permits either a successful stop or a continued takeoff when operating at the minimum allowable field length for a particular weight

The operational bite: the go/no-go decision is made before V1 so that deceleration can begin no later than V1. If braking has not begun by V1, the decision to continue has been made by default (AC 120-62, "Takeoff Safety Training Aid," quoted in AFH ch. 16).

Most manufacturers have operators identify a low-speed regime (80 knots and below) and a high-speed regime (100 knots and above) (AFH ch. 16):

• Low-speed regime: abort for any malfunction or abnormality, actual or suspected
• High-speed regime: reject only for catastrophic malfunctions or life-threatening situations — engine failure, fire or smoke, a takeoff warning system, loss of directional control — weighing the threat against the risk of an overrun

AA.III.I.K1 lists the classic triggers: takeoff warning systems, powerplant failure, other systems warnings or failures. AFH adds unsuspected equipment on the runway, bird strike, blown tires, ATC instruction, and significant abnormalities like split airspeed indications. Above the split, most of that list becomes a reason to continue and handle it airborne.

Although only about 2 percent of rejected takeoffs are high-speed, aborts above 120 knots account for the vast majority of RTO overrun accidents (AFH ch. 16). The physics behind it:

• Delaying the maneuver just one second beyond V1 adds 4 to 6 knots on average
• Crews require 3 to 7 seconds to identify an impending RTO and execute the maneuver
• Ill-advised reject decisions and improper technique together contribute to a majority of takeoff-related commercial aviation accidents worldwide

A brief moment of indecision is the difference between stopping on pavement and running off the end — which is why the decision architecture is briefed before brake release, not improvised at 130 knots.

The stopping sequence (AFH ch. 16):

1. Maximum braking immediately, simultaneously retarding the throttles
2. Spoiler extension
3. Thrust reverser deployment, following in short sequence

This is not normal after-landing braking; treating it like one is the documented failure mode. Brakes provide the most effective stopping force; delaying them when every second counts stretches the stopping distance. Cautions:

• Differential braking for directional control diminishes total braking effectiveness — tire friction is shared between stopping and steering
• A blown tire eliminates braking on that wheel and can cascade to adjacent tires

The ACS skill: promptly reduce power and maintain positive aircraft control, using drag and braking devices as appropriate, to come to a stop (AA.III.I.S3).

• Minimum V1 — the lowest permissible V1 from which the takeoff can still be safely completed after critical engine failure at the designated speed
• Maximum V1 — the highest V1 at which a reject can be initiated and the airplane stopped within the remaining runway or runway and stopway
• Reduced V1 — a V1 below maximum (or normal) V1 but above minimum V1, selected to shrink the required RTO stopping distance — used chiefly to offset degraded stopping capability on wet or contaminated runways, while buying roughly 2 seconds of recognition time for the crew (AC 120-62 terms, reproduced in AFH ch. 16)

FAA-approved takeoff data reflects performance demonstrated in ideal conditions — a clean, dry runway with maximum braking — and does not credit reverse thrust in computing stopping distance (AFH ch. 16). Real stopping performance can be degraded by, among others:

• Reduced runway friction and contaminants — rubber and oily residue, standing water, snow, slush, ice
• Wind direction and velocity, and low air density
• Flap and bleed configuration
• Underinflated or failing tires, deficient brakes or RTO autobrakes, inoperative anti-skid
• Penalizing MEL or CDL items
• Pilot technique and proficiency

This is why the runway selection risk element (AA.III.I.R1) is graded against limitations, available distance, surface conditions, and wind — the paper number is a ceiling, not a promise.

• ASEL/ASES: reject the takeoff if the powerplant failure occurs prior to becoming airborne (AA.III.I.S1) — there is no continue option
• AMEL/AMES: reject if the powerplant failure occurs at a point where the rejected takeoff procedure can be initiated and the airplane can be safely stopped on the remaining runway/waterway (AA.III.I.S2)

Test-day safety note from ACS Appendix 3: in a multiengine airplane, the simulated powerplant failure must be introduced before reaching 50 percent of VMC.

• Coordinate with the crew: complete the appropriate procedures, checklists, and radio calls in a timely manner (AA.III.I.S4)
• Treat it as an emergency: a rejected takeoff should be perceived as an emergency (AFH ch. 16)
• Keep priorities straight: the primary objective is not necessarily to stop in the shortest distance, but to maintain control of the airplane as it decelerates; in some situations it is preferable to continue into the overrun area under control rather than risk directional control loss, landing gear collapse, or tire/brake failure trying to stop short (AFH ch. 13)

SOPs should include a speed callout during the transition from the low-speed to the high-speed regime (AFH ch. 16). It does four jobs at once:

• Reminds both pilots the critical decision window is opening
• Provides a last opportunity to crosscheck instruments and verify airspeed
• Confirms adequate takeoff thrust is set
• Performs a pilot incapacitation check through the challenge-and-response ritual — a callout that goes unanswered is itself a reject trigger

Fly your operator's phrasing; the point is that the callout is a checklist item disguised as a number.

To keep the crew from trading a manageable airborne problem for an unnecessary high-speed reject: some manufacturers inhibit aural or visual malfunction warnings of non-critical equipment beyond a preset speed to prevent overreaction and a risky high-speed RTO when a safer option is to take the non-critical malfunction into the air (AFH ch. 16). Know your type's inhibit logic — it is part of the answer to "what would make you reject at 130 knots?" because the airplane has already filtered the list for you.

The pilot flying (pilot in command) makes the decision to continue or reject a takeoff for any reason, even though the pilot monitoring watches the engine instruments throughout the roll; a reject decision requires immediate retarding of the thrust levers (AFH ch. 16). But the decision criteria were fixed before brake release: the ACS-required takeoff briefing covers abnormal or emergency procedures prior to or after reaching decision speed (V1 or VMC) and what each crewmember does (ACS Appendix 3). On the roll you are not deciding what justifies a reject — you are pattern-matching against a briefed list, which is what makes a 1-to-2-second response physically possible.

Five measures stand out — useful when the examiner asks how operators manage this risk (AFH ch. 16):

• SOPs advancing the expanded V1 definitions, including progressive callouts marking the low-to-high-speed transition
• CRM training that sharpens recognition of emergency versus abnormal situations
• Crews carefully considering factors that compromise published performance data
• Expanded practical training in the proper use of brakes, throttles, spoilers, and reverse thrust during RTO demonstrations
• Manufacturers eliminating non-critical malfunction warnings during the roll at preset speeds

Task III.I is one of the load-bearing Tasks of the ACS, showing up across certificate actions (Appendix 1):

• An AMEL type rating tests Area III Tasks A, B, I, and J (sea classes test all of Area III)
• Removing a Second-in-Command Required limitation requires demonstrating single-pilot competency on Area III Tasks including Task I
• Center-thrust limitation removal requires Task III.I in a multiengine airplane with a published VMC

If your certificate action involves a multiengine airplane, plan on flying this maneuver.

Light twin: accelerate-stop distance is typically advisory data in the AFM/POH — it becomes a limitation only when published in the limitations section, and no regulation requires the runway to equal or exceed it. Experienced multiengine pilots still treat runway length of at least accelerate-stop distance as a matter of safety and good operating practice (AFH ch. 13).

Transport jet: the picture inverts — V1 exists precisely because the takeoff data ties decision speed, field length, and engine-out continuation together, and your operator's performance system enforces it on every takeoff (AFH ch. 16).

If your checkride is in a jet, answer from the V1 framework; if it is in a piston twin, know that the "balanced" guarantee may not exist in your AFM at all.