1. INTRODUCTION

The Altimeter Setting Procedures in use generally conform to those contained in ICAO Doc 8168 - Procedures for Air Navigation Services - Aircraft Operations (PANS-OPS), Volume III, Section 2 and are given in full below.

Information on the QNH and air temperature for use in determining adequate terrain clearance and transition level is provided in MET reports, ATIS broadcasts or transmitted by the appropriate ATS unit.

QNH values are given in hectopascals (HPA) rounded down to the nearest lower whole hectopascal.

2. BASIC ALTIMETER SETTING PROCEDURES

2.1 Transition altitude

The transition altitude within the entire Riga FIR is 5000 ft (1500 m) AMSL.

2.2 Transition level

The transition level is the lowest flight level available for use and located at least 1000 ft (300 m) above the transition altitude to permit the transition altitude and the transition level to be used concurrently in cruising flight, with vertical separation ensured, and it will be calculated according to the following table:

Transition altitude 5000 FT
QNH value	Transition level
901 - 942	85
943 - 959	80
960 - 977	75
978 - 995	70
996 - 1013	65
1014 - 1031	60
1032 - 1050	55
1051	50

2.3 Take-off and climb

A QNH altimeter setting is made available to aircraft during taxi clearance, prior to take-off. QFE values will be given on request only.

Vertical positioning of aircraft during climb is expressed in terms of altitudes until the transition altitude is reached above which vertical positioning is expressed in terms of flight levels.

2.4 En-route

For en-route flight which implies that the aircraft will be flying at an altitude equal to or lower than the transition altitude, ATS unit will inform aircraft about the altimeter setting to be used within the area concerned.

2.5 Approach and landing

A QNH altimeter setting is made available during approach clearance and during clearance to enter the traffic circuit.

QFE altimeter settings will be given on request only.

Vertical positioning of aircraft during approach is controlled by reference to flight levels until the transition level is reached, below which vertical positioning is controlled by reference to altitudes.

2.6 Missed approach

The relevant portions of 2.3 and 2.5 shall be applied in the event of a missed approach.

3. DESCRIPTION OF ALTIMETER SETTING REGION(S)

3.1 Altimeter setting regions

Lateral limits of altimeter setting regions within Riga FIR are corresponding to the GAMET/AIRMET areas in GEN 3.5.

3.2 Regional QNH

Regional QNH is a forecast of minimum value of QNH within Riga FIR sub-areas for a specified time period.

Forecast of the minimum QNH values for sub-areas is provided in GAMET according to GEN 3.5.4.

3.3 Description of aerodrome related QNH areas

During flight at or below the transition altitude the following pressure shall be set on altimeter:

a. within Riga CTR, Liepaja FIZ Sector B and FIZ Sector A - QNH of the aerodrome;

b. within Riga TMA B and a layer 1000 ft (300 m) below* - QNH of aerodrome Riga;

c. within Riga TMA C and a layer 1000 ft (300 m) below* - QNH of aerodrome Lielvarde;

d. all other airspace is part of the forecast QNH altimeter setting region system.

* It concerns flights in airspace just below the lower limit of TMA, during which it could come to unintended and undesirable penetration of TMA when the pressure is set up incorrectly.

3.4 Lower limit of controlled airspace

Lower limit of controlled airspace defined by altitude (AMSL) is always references to the QNH of:

a. Riga TMA A - Regional QNH;

b. Riga TMA B - Riga aerodrome QNH;

c. Riga TMA C - Lielvarde aerodrome QNH.

4. PROCEDURES APPLICABLE TO OPERATORS (INCLUDING PILOTS)

4.1 Flight planning

The levels at which a flight is to be conducted shall be specified in a flight plan:

1. In terms of flight levels if the flight is to be conducted at or above the transition level, and

2. In terms of altitudes if the flight is to be conducted at or below the transition altitude.

Note: Flight levels and altitudes are specified in a flight plan by number not in terms of FT or M.

4.2 Corrections of altimeter setting

The pilot is responsible for corrections to altimeter settings as described in Doc 8168 (PANS-OPS). If an aircraft is cleared by ATC to an altitude which the pilot-in-command finds unacceptable due to low temperature or any other operational requirement then the pilot-in-command shall request an alternative altitude. If such a request is not received ATC will consider that the clearance has been accepted and will be complied with.

5. TABLE OF CRUISING LEVELS

The cruising levels to be observed when so required are as follows:

MAGNETIC TRACK
From 000 degrees to 179 degrees						From 180 degrees to 359 degrees
IFR Flights			VFR Flights			IFR Flights			VFR Flights
Altitude			Altitude			Altitude			Altitude
FL	Metres	Feet	FL	Metres	Feet	FL	Metres	Feet	FL	Metres	Feet
010	300	1000	-	-	-	020	600	2000
030	900	3000	035	1050	3500	040	1200	4000	045	1350	4500
050	1500	5000	055	1700	5500	060	1850	6000	065	2000	6500
070	2150	7000	075	2300	7500	080	2450	8000	085	2600	8500
090	2750	9000	095	2900	9500	100	3050	10000	105	3200	10500
110	3350	11000	115	3500	11500	120	3650	12000	125	3800	12500
130	3950	13000	135	4100	13500	140	4250	14000	145	4400	14500
150	4550	15000	155	4700	15500	160	4900	16000	165	5050	16500
170	5200	17000	175	5350	17500	180	5500	18000	185	5650	18500
190	5800	19000	195	5950	19500	200	6100	20000	205	6250	20500
210	6400	21000	215	6550	21500	220	6700	22000	225	6850	22500
230	7000	23000	235	7150	23500	240	7300	24000	245	7450	24500
250	7600	25000	255	7750	25500	260	7900	26000	265	8100	26500
270	8250	27000	275	8400	27500	280	8550	28000	285	8700	28500
290	8850	29000				300	9150	30000
310	9450	31000				320	9750	32000
330	10050	33000				340	10350	34000
350	10650	35000				360	10950	36000
370	11300	37000				380	11600	38000
390	11900	39000				400	12200	40000
410	12500	41000				430	13100	43000
450	13700	45000				470	14350	47000
490	14950	49000				510	15550	51000
etc.	etc.	etc.				etc.	etc.	etc.