---
license: mit
task_categories:
- automatic-speech-recognition
language:
- en
tags:
- air-traffic-control
- atc
- synthetic-speech
size_categories:
- 1M<n<10M
configs:
- config_name: STEAK-rare
  default: true
  data_files:
  - split: train
    path: data/STEAK-rare/train-*.parquet
  - split: test
    path: data/STEAK-rare/test-*.parquet
- config_name: STEAK-medium
  data_files:
  - split: train
    path: data/STEAK-medium/train-*.parquet
  - split: test
    path: data/STEAK-medium/test-*.parquet
- config_name: STEAK-tough
  data_files:
  - split: train
    path: data/STEAK-tough/train-*.parquet
  - split: test
    path: data/STEAK-tough/test-*.parquet
---

# STEAK — **S**peech-to-**T**ext for **E**rror of **A**tc readbac**K**

STEAK is a **synthetically generated** dataset of **ATCO–pilot radio exchanges**
— both the **text** and the **audio** are synthetic:

- **Text**: assembled by **formal rules**, following an **ontology of ATCO–pilot
  exchanges**.
- **Audio**: **TTS** → voice **timbre / accent** conversion (**seed-vc**) →
  **noise** addition (noise captured from real **ATCO2** recordings).

**One row = one audio** (one ATCO controller utterance *or* one pilot readback).
**2,519,694 audios.** The **ATCO↔pilot pair is always present**: both roles of an
exchange share the same `pair_id`. To rebuild the complete pairs directly:

```python
from collections import defaultdict
from datasets import load_dataset, concatenate_datasets

subsets = ["STEAK-rare", "STEAK-medium", "STEAK-tough"]
ds = concatenate_datasets(
    [load_dataset("DEEL-AI/STEAK", s, split="train") for s in subsets]
)

pairs = defaultdict(dict)
for ex in ds:
    pairs[ex["pair_id"]][ex["role"]] = ex   # {'atco': ..., 'pilot': ...}

pair = pairs["0000001"]
atco, pilot = pair.get("atco"), pair.get("pilot")
```

## Text generation (formal rules + ATC ontology)

82 commands in total can be generated (full table below). An utterance
contains **at most 7** (1 *seed* command + up to 6 added) and **2.2 on
average** (1 seed + ~1.2 added). The **first (seed) command** is drawn at random
among the 82 with a **weighting** (not all equally likely): the weights
come from **EDA observations** on the real ATC corpora **ATCO2** and
**UWB-ATCC**, so that the en-route core (climb/descend/heading/contact…)
dominates and rare commands stay rare. **Multiple phrasings per command**: each
command has several controller-side phrasings, and several ways to be **read
back** on the pilot side — each phrasing is drawn at random with a weighting
obtained from our EDA observations on ATCO2 and UWB-ATCC. The readback phrasing
is **not necessarily** the same as the instruction (sometimes reduced to the
value alone, *“level 100”*).

We also added **incompatibility rules** within a single utterance: at most **one
command per group** (never two vertical commands, nor two heading commands,
etc.), vertical-direction coherence (no *“climb … rate of descent”*),
ground/flight exclusivity (no *“taxi … descend FL90”*) and phase conflicts
(departure ⊥ arrival…).

The concrete values (waypoints, station names & frequencies, airports,
airlines/callsigns) come from **public sources**:

| resource | source |
|---|---|
| waypoints | [OpenNav](https://opennav.com/waypoint/FR) (one page per country) |
| ICAO airports | [OpenNav](https://opennav.com/airportcodes) |
| ATC stations + frequencies | [VATEUD](https://fsmine.dhis.org/vateud8/) |
| airlines / callsigns (telephony) | [Wikipedia](https://en.wikipedia.org/wiki/List_of_airline_codes), [flugzeuginfo.net](https://www.flugzeuginfo.net/), [OpenNav](https://opennav.com/airlinecodes/), [FAA CNT](https://www.faa.gov/air_traffic/publications/atpubs/cnt_html/) |
| seed-vc reference voices (accent, `accent_ref`) | [Speech Accent Archive](https://accent.gmu.edu) |

### The 82 commands and their value domains

The 82 commands are grouped **by family** (vertical, heading, speed…).

<details>
<summary>Show the 82 commands and their value domains</summary>

| command type | value domain |
|---|---|
| Vertical — climb / descend / level (climb, descend, maintain, stop climb/descent, rate of climb/descent…) | flight level **FL060–FL400** (steps of 10) or altitude **2000–15000 ft** (steps of 1000) ; vertical rate **500–3000 ft/min** |
| Approach & landing (cleared to land, cleared ILS / VOR / NDB / DME / visual approach, touch-and-go) | **runway 01–36** (+ suffix **L / R / C**) |
| Waypoint & route navigation (direct to, inbound, cross waypoint ; follow route / STAR arrival / SID / transition) | a single **waypoint** (OpenNav), optionally + FL, for direct-to / inbound / cross ; **or** a whole **named published route** for follow-route — named after its reference fix: a **SID** (standard departure), a **STAR** (standard arrival), or a **transition** (the segment linking an en-route point to a SID/STAR) |
| Ground runway movements (cross runway, hold short, line up, backtrack, vacate) | **runway 01–36** (+ suffix **L / R / C**) ; for *vacate*, a **taxiway id** (a phonetic letter, optionally + a number or a 2nd letter — e.g. `A`, `L`, `A48`) |
| Heading (turn left/right, turn by N°, fly heading) | an **absolute heading 005–360°** (multiples of 5 — *“fly heading 230”*) ; **or** a **relative turn** left/right of **{10, 20, 30, 40, 90, 180, 270, 360}°** (*“turn right by 30 degrees”*) |
| QNH | **975–1045 hPa** |
| Transponder (squawk, ident) | **0000–7777 octal** code (emergency/reserved codes 7500/7600/7700/7777/0000 excluded) ; *ident* takes no value |
| Speed (speed, reduce / increase speed, maintain speed, mach) | **160–340 kt** (steps of 10), or **Mach 0.70–0.86** (steps of 0.01) |
| Frequency transfer (contact, monitor) | **station + frequency 118.000–136.xxx MHz** (source VATEUD) |
| Ground & departure (startup, pushback, taxi to / via, hold position) | a **taxiway id** (phonetic letter, optionally + number — `A`, `A48`) ; no value for *startup / pushback / hold position* |
| Time constraint (time) | **hhmm time** (+ waypoint) |
| Holding | a **waypoint** (OpenNav) |
| Information (ATIS, active runway, traffic, wind, destination, CTR entry) | ATIS **alpha…zulu** ; active runway **01–36** ; traffic as a relative position (« x o'clock y miles »…) ; wind **direction / speed / gust** ; destination **airport (ICAO, OpenNav)** ; **CTR entry waypoint** |
| Replies & initiation (affirm, standby, go ahead, initial call) | — (no value) |

</details>

A command may carry a **condition** — a temporal/spatial trigger attached to it.

<details>
<summary>The 26 condition connectors (« … » = generated value)</summary>

| connector | attaches to commands |
|---|---|
| « when ready » | direct-to / inbound, frequency contact, vertical (climb / descend / maintain…) |
| « when able » | direct-to / inbound, vertical (climb / descend / maintain…) |
| « when established » | approach, vertical (climb / descend / maintain…) |
| « when passing … feet » | vertical (climb / descend / maintain…) |
| « until further advised » | heading, speed, vertical (climb / descend / maintain…) |
| « until passing flight level … » | vertical (climb / descend / maintain…) |
| « until … » | direct-to / inbound, vertical (climb / descend / maintain…) |
| « until … miles » | speed, vertical (climb / descend / maintain…) |
| « after … » | direct-to / inbound, heading, vertical (climb / descend / maintain…) |
| « after … then … » | direct-to / inbound, heading, vertical (climb / descend / maintain…) |
| « after the low approach » | heading, vertical (climb / descend / maintain…) |
| « after departure » | direct-to / inbound, vertical (climb / descend / maintain…) |
| « level by … » | vertical (climb / descend / maintain…) |
| « before … » | direct-to / inbound, vertical (climb / descend / maintain…) |
| « at … feet per minute » | vertical (climb / descend / maintain…) |
| « at … feet per minute or greater » | vertical (climb / descend / maintain…) |
| « time … » | cross waypoint, direct-to / inbound, vertical (climb / descend / maintain…) |
| « from present » | direct-to / inbound, heading, vertical (climb / descend / maintain…) |
| « from present position » | direct-to / inbound, heading |
| « if able » | direct-to / inbound, speed, vertical (climb / descend / maintain…) |
| « if possible » | direct-to / inbound, speed, vertical (climb / descend / maintain…) |
| « if available » | vertical (climb / descend / maintain…) |
| « until … miles final » | approach, speed, vertical (climb / descend / maintain…) |
| « on conversion » | speed |
| « when established on the localizer » | approach, speed, vertical (climb / descend / maintain…) |
| « when you are done de icing » | frequency contact |

</details>

**At most 2 conditions per utterance.** The probability of having a condition in
an utterance is **0.08**, and of having 2 conditions
**0.08 × 0.18 = 0.0144**. The command
the condition is applied to is drawn at random, and on the pilot side the
condition is read back with probability **0.55**. The
condition appears in the `commandes` column (`atco_condition`) and, if read back,
in `pilot_condition_readback`.

## Audio rendering: voice, accent, noise

The text is then synthesized and degraded to resemble a real ATC frequency:

- **Voice / timbre**: each utterance is synthesized by **Kokoro TTS**, with a
  **voice drawn at random** among the Kokoro voices (column `voice`).
- **Accent (voice conversion)**: seed-vc then transfers the voice of a reference
  clip onto the synthesis. The reference clips (column `accent_ref`) are scraped
  from the [Speech Accent Archive](https://accent.gmu.edu) (≈ 3000 speakers of
  all native languages reading the same paragraph → varied accents). The pool is
  split by gender and the share of male voices is drawn per role (≈ 0.7 ATCO /
  ≈ 0.9 pilot).
- **Noise**: a noise profile from **real ATCO2 recordings** is added (column
  `atco2_noise_profile`). No reverberation (small, absorptive ATC cabins →
  negligible T60).

<video controls width="100%" src="https://huggingface.co/datasets/DEEL-AI/STEAK/resolve/main/media/noise_chain.mp4">
Your browser does not support the video tag — <a href="https://huggingface.co/datasets/DEEL-AI/STEAK/resolve/main/media/noise_chain.mp4">download it</a>.
</video>

## Difficulty (measured-RMS tercile)

Difficulty = tercile of the **RMS measured on the rendered WAV** (column `rms`).

The **RMS** (*root-mean-square*) is the **effective signal level**: the average
energy/volume of the audio over its whole duration. It is expressed in **dBFS**
(decibels relative to full scale: 0 dBFS = full scale), so always ≤ 0; the
**closer to 0**, the **louder / more energetic** the audio. Since the audio is
**peak-normalized** at the channel output (peak fixed at 0 dBFS), the RMS — which
includes the background noise and the soft-clip fold-back — is **comparable
across files**. **High RMS = noisy audio = harder.**

| subset | rms bounds (dBFS) |
|---|---|
| `STEAK-rare` (easy, clean) | `<= -13.08` |
| `STEAK-medium` | `]-13.08, -11.55]` |
| `STEAK-tough` (hard, noisy) | `> -11.55` |

## Train / Test split

| subset | train | test | total |
|---|---|---|---|
| STEAK-rare | 419,716 | 420,218 | 839,934 |
| STEAK-medium | 420,434 | 419,479 | 839,913 |
| STEAK-tough | 419,864 | 419,983 | 839,847 |

The `train`/`test` split (~50% test) is cut **by pair** (`pair_id`): a
pair is **always entirely in `train` OR entirely in `test`**, never one role in
`train` and the other in `test` — no atco↔pilot leakage between the two splits.
This holds **regardless of subset**: the two roles may fall into different
difficulty subsets (`STEAK-rare`/`-medium`/`-tough`, depending on their own
noise), but they **always share the same split**.