# MtrBase

Base Military Training Route (MTR) records containing route identification, associated FSSs, and times of use

**Source:** NASR table `MTR_BASE` · version `e25086c3e952` · effective 2026-04-16

> Ordered by ROUTE_TYPE_CODE, ROUTE_ID. The ordered-by list is also the unique record key.

## Example query

```graphql
# Introspect the MtrBase type in GraphiQL at https://api.nav.sortie.co/graphql
# Example shape (pair with a compatible root query field):
{
  # ...rootQuery... {
    effDate
    routeTypeCode
    routeId
    artcc
  # }
}
```

Run at https://api.nav.sortie.co/graphql (GraphiQL available in-browser).

## Fields

| Field | Type | Description | Units | Enum |
|---|---|---|---|---|
| `effDate` | `String` | The 28 Day NASR Subscription Effective Date in format YYYY/MM/DD |  |  |
| `routeTypeCode` | `RouteTypeCode` | MTR Type Code indicating whether the route is IFR or VFR |  | `IR`=IFR; `VR`=VFR |
| `routeId` | `String` | Route Identifier. Along with ROUTE_TYPE_CODE creates a unique MTR identifier |  |  |
| `artcc` | `String` | List of ARTCC Idents that the MTR traverses. Multiple ARTCCs separated by spaces when route crosses multiple centers |  |  |
| `fss` | `String` | All Flight Service Station (FSS) Idents within 150 nautical miles of the route. Multiple FSS idents separated by spaces | nautical miles |  |
| `timeOfUse` | `String` | Times of Use text information describing when the MTR is active |  |  |

## Column provenance

Every field maps 1:1 to a column in the `MTR_BASE` table of `nasr.db`. Original FAA column names:

| GraphQL field | SQLite column |
|---|---|
| `effDate` | `EFF_DATE` |
| `routeTypeCode` | `ROUTE_TYPE_CODE` |
| `routeId` | `ROUTE_ID` |
| `artcc` | `ARTCC` |
| `fss` | `FSS` |
| `timeOfUse` | `TIME_OF_USE` |