My Travel A320 in the Snowdrift!
Forewarned is Forearmed
Join Date: Nov 2003
Location: uk
Age: 60
Posts: 227
Likes: 0
Received 0 Likes
on
0 Posts
I thought these Airports in snow bound areas had the clearance & de- Icing of runways down to a fine Art, as well as runway friction testing & passing on of information under these conditions to Aircrew spot on. 
Thread Starter
Join Date: Sep 2003
Location: 59°45'36N 10°27'59E
Posts: 1,032
Likes: 0
Received 0 Likes
on
0 Posts
Well we do, ( 
) but it is different to operate in these conditions.
When the conditions are like they have been the last 2 weeks (cold and percipitation), you cannot as you say de-ice the runway. Sweeping and if needed sandning is the only viable option. (Cemicals is a non-starter due to low tempratures in the air and runway body)
The snowtam on the web just prior to the incident was
Granted, not summer conditions, but well inside normal operating conditions.
But........when some foreign aircrew (let's not name the airline) don't know if "65" in friction is in the "Good" or "Medium" range, we have a problem.
) but it is different to operate in these conditions.When the conditions are like they have been the last 2 weeks (cold and percipitation), you cannot as you say de-ice the runway. Sweeping and if needed sandning is the only viable option. (Cemicals is a non-starter due to low tempratures in the air and runway body)
The snowtam on the web just prior to the incident was
SWEN0090 ENEV 11251950
(SNOWTAM 0090 A) ENEV B) 11251950
C) 17 F) 47/47/47 G) 8/8/8 H) 34/32/32/SKH
N) 487
R) 487
T) 50PCT DRY SNOW ON SANDED ICE)
(SNOWTAM 0090 A) ENEV B) 11251950
C) 17 F) 47/47/47 G) 8/8/8 H) 34/32/32/SKH
N) 487
R) 487
T) 50PCT DRY SNOW ON SANDED ICE)
But........when some foreign aircrew (let's not name the airline) don't know if "65" in friction is in the "Good" or "Medium" range, we have a problem.
Join Date: Jun 2001
Location: phoenix, AZ, USA
Posts: 245
Likes: 0
Received 0 Likes
on
0 Posts
I wonder how they set the T/O thrust?. Lots of guys I flew with on sparky the wonderjet loved to just slam it into TOGA (which I assumed they used due to the crappy wx). The FADECs can be a little slow and if one side went max thrust significantly before the other then that could easily have put them in the snowbank, especially if there were a x-wind. How wide was the runway plowed?
Join Date: Mar 2000
Location: Arizona USA
Posts: 8,571
Likes: 0
Received 0 Likes
on
0 Posts
Hmmm, that's why I always preferred a four engine type in slippery snow conditions...lots, or maybe a little diffenental thurst from outboards or inboards as needed, for control.
Worked in the 707 anyway. Especially up Scandy way, where it could indeed be slippery.
Worked in the 707 anyway. Especially up Scandy way, where it could indeed be slippery.
Thread Starter
Join Date: Sep 2003
Location: 59°45'36N 10°27'59E
Posts: 1,032
Likes: 0
Received 0 Likes
on
0 Posts
How wide was the runway plowed?
Join Date: Jun 2000
Location: head in the clouds
Posts: 68
Likes: 0
Received 0 Likes
on
0 Posts
Slippery runways are the norm at those lats., and braking action reports a tad unreliable at times.
If you´re not used to it, it´s easy to get in deep.
A certain southern european airline used to do charters into the area. While the local boys off loaded pax to keep the weight down and compensate for .25 and below on t.o., the charter guys would go fully loaded. Apparently there was no such thing as an entry for braking action in their max gwc charts...
If you´re not used to it, it´s easy to get in deep.
A certain southern european airline used to do charters into the area. While the local boys off loaded pax to keep the weight down and compensate for .25 and below on t.o., the charter guys would go fully loaded. Apparently there was no such thing as an entry for braking action in their max gwc charts...
Join Date: Aug 2003
Location: SE Asia - oops redundant
Posts: 68
Likes: 0
Received 0 Likes
on
0 Posts
M609 refers to ' well within normal operating conditions'
The snowtam has braking action 34/32/32 SKH. These SKH values put the runway braking action in the Medium-Poor category ( bearing in mind they are SKH values). Admittedly these braking action readings are at first glance acceptable until you refer to the measuring medium. Medium-Poor is not acceptable for T/O in my airline.
The snowtam has braking action 34/32/32 SKH. These SKH values put the runway braking action in the Medium-Poor category ( bearing in mind they are SKH values). Admittedly these braking action readings are at first glance acceptable until you refer to the measuring medium. Medium-Poor is not acceptable for T/O in my airline.
Thread Starter
Join Date: Sep 2003
Location: 59°45'36N 10°27'59E
Posts: 1,032
Likes: 0
Received 0 Likes
on
0 Posts
Medium-Poor is not acceptable for T/O in my airline.
The fact that you use the "Medium-Poor" therm, and not the actual breaking action speaks volumes.
T/O in BA around 20 with 737-5/700 on a 2300 meter runway in little/no crosswind is not unheard of, weight permitting offcourse. BA 30 is allmost never a problem.
I have still to experience local crews to reject 30 in zero cross/tailwind conditions.
That said, the rules for runway clearing clearly states, that when BA is less then 35, you have to try and improve it. (If possible) But, if you have an airport that have movements with larger aircraft, (Widebody etc) you pretty much need summer condtions.
Any SAS, WIF, LTR and BRA pilots, feel free to correct!
To quote the worlds favourite:
"Various states and airports each have their own method of measuring runway friction e.g. Mu meter, SAAB friction tester, Tapley meter, Skiddometer etc, but, as stated above none are truly representative of a braking aicraft, for this reason XXX prefers to use the estimated braking coefficient quoted in snowtams and other met statements as one of six categories ranging from good to unreliable."
So we face a dilema!
Intereseted to hear how the 'locals' approach the problem.
"Various states and airports each have their own method of measuring runway friction e.g. Mu meter, SAAB friction tester, Tapley meter, Skiddometer etc, but, as stated above none are truly representative of a braking aicraft, for this reason XXX prefers to use the estimated braking coefficient quoted in snowtams and other met statements as one of six categories ranging from good to unreliable."
So we face a dilema!
Intereseted to hear how the 'locals' approach the problem.
Extracts from a safety presentation; ERA Icing workshop 2002.
Conclusion:
There is no overall accepted “certification to operational correlation” between mu meters and airplanes.
Some of the preceding points:-
Runway Condition and Braking Definitions
ICAO - Damp, Wet, Water Patches, Flooded
JAR Ops 1.480 - Dry, Damp, Wet, Contaminated
JAA Certification - Water, Slush, Wet Snow, Dry Snow, Compacted Snow, Specially prepared Winter Runway, Ice
Manufacturer - Slippery? contaminant depth?
ATC - Good, Medium, Poor, nil
Operational requirements- JAR Ops 1.490 & 1.520
ATC rely on runway friction devices and reports from other crews, both can provide incorrect or confusing information
Runway Friction Measurement Devices - No International standard for Friction devices. Accuracy of friction devices depends on contaminant type and design of device. No correlation to Certification friction levels or IATA terminology
Crew Reports - Level of “friction” is based on retardation and is therefore aircraft type specific.
… Confused???
Conclusion:
There is no overall accepted “certification to operational correlation” between mu meters and airplanes.
Some of the preceding points:-
Runway Condition and Braking Definitions
ICAO - Damp, Wet, Water Patches, Flooded
JAR Ops 1.480 - Dry, Damp, Wet, Contaminated
JAA Certification - Water, Slush, Wet Snow, Dry Snow, Compacted Snow, Specially prepared Winter Runway, Ice
Manufacturer - Slippery? contaminant depth?
ATC - Good, Medium, Poor, nil
Operational requirements- JAR Ops 1.490 & 1.520
ATC rely on runway friction devices and reports from other crews, both can provide incorrect or confusing information
Runway Friction Measurement Devices - No International standard for Friction devices. Accuracy of friction devices depends on contaminant type and design of device. No correlation to Certification friction levels or IATA terminology
Crew Reports - Level of “friction” is based on retardation and is therefore aircraft type specific.
… Confused???