Metar decoding

[torob]

Hi,

I came across the following metar;

METAR EBLG 090750Z 27011KT 5000 -SHSN SCT003 BKN005 00/M01 Q1022 R23L/729195 TEMPO FM0815 1000 SHSN BKN003=

I'm a bit confused about R23L/729195

If I get it right, I understand that RWY 23L is covered with ice (7) from 11% to 25% (2) and its braking action is good (95)
But what about that '91'? It should stand for the depth of deposit but '91' is not used for this information or do I miss something?

Thanks a lot for your help

[Sam Dodger]

RUNWAY REPORTS EUROPE. Information on RWY conditions expressed by one or more 8-figure groups appended to the METAR.
MOTNE runway reports code AABCDDEE.


1st and 2nd figure RUNWAY DESIGNATOR

PARALLEL RWY:s The right RWY is identified by adding 50 to the Designator, e.g 77=27R, while the left RWY only the RWY figures appears e.g 27=27L
The figure 88 instead of a RWY designator indicates that conditions reported apply to all RWY at the Aerodrome.
The figure 99 instead of a RWY designator indicates that a previous RWY report is repeated.
--------------------------------------------------------------------------------

3rd figure TYPE OF DEPOSIT


0= CLEAR and DRY
1= DAMP
2= WET or Water Patches
3= RIME or FROST (<1mm)
4= DRY SNOW 5= WET SNOW
6= SLUSH
7= ICE
8= COMPACTED or ROLLED SNOW
9= FROZEN RUTS or RIDGES
/= TYPE of DEPOSIT NOT REPORTED, e.g due to RWY clearance/de-icing i progress.
--------------------------------------------------------------------------------

4th figure EXTENT OF CONTAMINATION
1= 10% or less of RWY covered
2= 11% to 25% of RWY covered
5= 26% to 50% of RWY covered
9= 51% to 100% of RWY covered
/= NOT REPORTED e.g due to RWY clearance or de-icing in progress.
--------------------------------------------------------------------------------

5th and 6th figure DEPTH OF DEPOSIT
00= less than 1mm
01 to 90= depth in mm, e.g 23=23mm
92= 10cm
93= 15cm
94= 20cm
95= 25cm 96= 30cm
97= 35cm
98= 40cm
99= RWY not operational due to snow, slush, ice, large drifts or RWY clearance. Depth not reported.
//= Depth operationally not significant e.g with ice or rolled snow, or not measurable e.g RWY wet.
--------------------------------------------------------------------------------

7th and 8th figure BRAKING CONDITIONS

Either the measured Friction Coefficient or an estimated Braking Action is reported as follows
FRICTION COEFFICENT
Reported figures from 01 to 90 represent FC, e.g 05=FC 0.05, 28=FC 0.28
BRAKING ACTION Reported by following code figures
91= POOR
92= MEDIUM/POOR
93= MEDIUM
94= MEDIUM/GOOD
95= GOOD
99= UNRELIABLE, BA and FC not possible to assess, misleading, e.g in case of aquaplaning.
//= RWY not operational, BA and FC not reported.

[CaptB737]

Yep. "91" seems an error to me

More than 90 should mean, more than 9 cm of a certain deposit.....
The change took place between 00h20 and 00h50 LT the 9th of December:

EBLG 082350Z 25006KT 4800 BR BKN014 M03/M04 Q1016 R23L/729195 BECMG 5000 BR=
EBLG 082320Z 24007KT 3500 BR BKN014 M03/M04 Q1015 R23L/290245 NOSIG=

So, within half an hour, 2 mm of Waterpatches----> 9,1 cm of Ice without any precipitation. Mmmm, not logic, unless the fire brigade did a firedrill test and hosed the runway

Look also to the "29" is used in both METAR's, only 1 position further
The same SNOWTAM is copied throughout the whole night.
Guess somebody must have been

[torob]

Thank you for the replies.

It also seemed to me that this was an error but was not quite sure.
And yes, that '29' shift seems to be a bit weird just like the combination of ice on the RWY (although it's just max 25%) with a good braking action didn't sound logically to me.