Holdover Table

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Holdover Table

'Formula I' & 'Formula I-Plus' Aircraft Ground Deicing Fluids

 

FAA Guideline for Holdover Times Anticipated for SAE Type I Fluid Mixture as a Function of Weather Conditions and OAT.

      CAUTION:  THIS TABLE IS FOR DEPARTURE PLANING ONLY AND SHOULD BE USED IN CONJUNCTION WITH PRE-TAKEOFF CHECK PROCEDURES.

 


OAT

Approximate Holdover Times Under Various Weather Conditions
(hours: minutes)

°C

°F

Frost*

Freezing Fog

Very

Light Snowuu

Light

Snowuu

Moderate

Snowuu

**Freezing

Drizzle

Light

Freezing

 Rain

Rain on Cold Soaked Wing

Other‡

-3 and above

27 and above

0:45

0:11 - 0:17

0:18-0:22

0:11 - 0:18

0:06 - 0:11

0:09 - 0:13

 0:02 - 0:05

0:02 - 0:05

CAUTION: 
No holdover time guidelines exist

below -3  to –6

below 27 to 21

0:45

0:08 - 0:13

0:14-0:17

0:08 - 0:14

0:05 - 0:08

0:05 - 0:09

 0:02 - 0:05

CAUTION: Clear ice may require touch for confirmation

below -6  to –10

below 21 to 14

0:45

0:06 - 0:10

0:11-0:13

0:06 - 0:11

0:04 - 0:06

0:04 - 0:07

 0:02 - 0:05

below
 -10

below   14

0:45

0:05 - 0:09

0:07-0:08

0:04 - 0:07

0:02 - 0:04

 

    °C     = Degrees Celsius                                 OAT      = Outside Air Temperature

    °F     = Degrees Fahrenheit                             FP        = Freezing Point

 

THE RESPONSIBILITY FOR THE APPLICATION OF THESE DATA REMAINS WITH THE USER.

*     During conditions that apply to aircraft protection for ACTIVE FROST

**   Use light freezing rain holdover times if positive identification of freezing drizzle is not possible

‡    Heavy snow, snow pellets, ice pellets, moderate and heavy freezing rain, hail

 

uu   TO USE THESE TIMES, THE FLUID MUST BE HEATED TO A MINIMUM TEMPERATURE OF 60°C (140°F) AT THE NOZZLE AND AT

 LEAST 1 LITER/M2 (» 2 GALS/100FT2) MUST BE APPLIED TO DEICED SURFACES
SAE Type I fluid/water mixture is selected so that the FP of the mixture is at least 10 °C (18 °F) below OAT.

 

CAUTIONS:

  • THE TIME OF PROTECTION WILL BE SHORTENED IN HEAVY WEATHER CONDITIONS.  HEAVY PRECIPITATION RATES OR HIGH MOISTURE CONTENT, HIGH WIND VELOCITY, OR JET BLAST WILL REDUCE HOLDOVER TIME BELOW THE LOWEST TIME STATED IN THE RANGE.  HOLDOVER TIME MAY BE REDUCED WHEN AIRCRAFT SKIN TEMPERATURE IS LOWER THAN OAT.
  • SAE TYPE I FLUID USED DURING GROUND DEICING/ANTI-ICING IS NOT INTENDED FOR -- AND DOES NOT PROVIDE -- PROTECTION DURING FLIGHT.

This Table may also be used for 'Formula X' in concentrations of 30/70% to 70/30% ('Formula X' / Water), with proper OAT buffer of 18°F / 10°C.

This Holdover Table is a guideline for use in departure planning, and should be used in conjunction with your pre-takeoff check procedures.  It presents an estimated range of time that the applied deicing fluid can be expected to be effective, dependent principally upon the outside air temperature and type of precipitate.  Note, however, that these times are variable with weather conditions, and that high rates of precipitation, high atmospheric moisture content, high wind velocity, and jet blast can reduce the estimated time of effectiveness.

Caution!! - The responsibility for the application of the data presented remains with the user.  A close visual and tactile inspection after deicing and immediately prior to takeoff is essential to assure that the aircraft is free of frost, snow, or ice accumulations.

Aircraft Deicing, Inc.     Voice and Fax:  866-268-3449
sales@aircraftdeicinginc.com      10/1/02 Data}
Source: See www.faa.gov/avr/AFS/afs200/afs220/hot2004.doc