Since many pilots fly in to or out of London Heathrow, it's worth mentioning the following optional RNAV (GNSS) Yankee Approach Trial effective from 0230 UTC 25 May to 2359 UTC 11 October 2017. If you want to fly these procedures on VATSIM, you should ‘Request RNAV Yankee’ on first contact with Heathrow Director.

I did not find any information on whether ATC will grant you the option to choose between the xisting and the the Trial procedures in this thread, although it's not technically a "change" in procedures. Either way, one is never not allowed to reqeust.

Full information below:

Issue Date: 2/4/2017
Effective: 25/5/2017
Number: 6/17
Incorporation: Next Revision

LONDON HEATHROW AIRPORT 3.2 DEGREE RNAV APPROACH TRIAL

INTRODUCTION
Additional RNAV approach procedures making use of a 3.2 degree Vertical Path Angle (VPA) have been designed for all four runways at Heathrow Airport.

In line with existing Approach with Vertical Guidance (APV) procedures in use at Heathrow, the trial procedures are based on GNSS and defined by lateral navigational accuracy of +/- 0.3 NM.

The trial 3.2 degree RNAV approaches are designated as follows:

- RNAV (GNSS) Y RWY 09R (Runway 09R)
- RNAV (GNSS) Y RWY 09L (Runway 09L)
- RNAV (GNSS) Y RWY 27R (Runway 27R)
- RNAV (GNSS) Y RWY 27L (Runway 27L)

This is a trial procedure due to start on 25 May 2017. Whilst the trial is in progress, crews should not expect to be cleared for the existing RNAV (GNSS) Z procedures.

Approaches will commence at the existing Intermediate Fixes (IF) and proceed to the new Final Approach Fixes (FAF) with
minimum altitudes of 2500 ft amsl. The FAFs will be new waypoints positioned along the extended runway centreline at a
distance calculated to allow for a descent of 3.2° to 50 ft above the landing threshold.

PURPOSE
The purpose of the trial is:

(a) To gain ATC and aircraft operator experience of RNAV 3.2° approach operations;
(b) To provide information on interactions between RNAV arrivals with an increased approach angle and existing traffic
proximate to the aerodrome;
(c) To assess the suitability of design criteria for RNAV 3.2° procedures;
(d) If possible, to assess the environmental impact of RNAV 3.2° approaches upon noise reduction;
(e) To assess the effect of warmer temperatures on the approach angle flown.

RNAV (GNSS) Y INSTRUMENT APPROACH PROCEDURE
The trial will be conducted under CAT I conditions only.

Pilots wishing to take part in the trial should ‘Request RNAV Yankee’ on first contact with Heathrow Director.

The PAPI lighting system has not been modified, and remains set at 3.0°. Pilots should exercise caution when using the PAPI lighting system during the final stages of the RNAV (GNSS) Y approaches.

Missed Approaches are designed to be flown conventionally by applying the existing published missed approach procedures to minimise impact to ATC operations. Missed Approaches use conventional navigation aids and are not available without I-AA DME, I-BB DME, I-LL DME, I-RR DME, and LON DME.

Radio Communication Failure Procedures:
In the event of a complete radio communications failure in an aircraft the pilot is to adopt the exisiting appropriate procedures detailed at ENR 1.1 3.4.2 except as detailed at EGLL AD 2.22 5 Loss of Communications Procedures (arriving aircraft).

In the event that the required navigation equipment fails, the flight crew shall advise ATC that they can no longer continue with the procedure, or are unable to accept the procedure, using the phraseology:
'(Callsign), unable RNAV due equipment.'

TRIAL IMPLEMENTATION DATE
This trial will be effective from 0230 UTC 25 May to 2359 UTC 11 October 2017.

Note:
The end of this trial may be subject to change due to data gathering requirements;
There may be further occasions where, due to ATC workload, weather avoidance or extraordinary airfield issues, the trial may not be practicable, and requests for the RNAV (GNSS) Y RWY XX L/R may be refused.

BAV OPERATIONS
Subject to the procedure being available in the aircraft navigation database, and subject to aircraft capability and equipment fit, BAV crews are encouraged to make use of the RNAV Y approaches when suitable once the trial commences in May.

Further information is available in UK AIP Supplement 006/2017.

If you have any queries about how to fly the new RNAV approaches, please contact your fleet training teams.