221 

Federal Aviation Administration, DOT 

§ 121.631 

fluid will prevent the formation of 
frost or ice and the accumulation of 
snow on the protected surfaces of an 
aircraft. Holdover time begins when 
the final application of deicing/anti- 
icing fluid commences and expires 
when the deicing/anti-icing fluid ap-
plied to the aircraft loses its effective-
ness. The holdover times must be sup-
ported by data acceptable to the Ad-
ministrator. The certificate holder’s 
program must include procedures for 
flight crewmembers to increase or de-
crease the determined holdover time in 
changing conditions. The program 
must provide that takeoff after exceed-
ing any maximum holdover time in the 
certificate holder’s holdover timetable 
is permitted only when at least one of 
the following conditions exists: 

(i) A pretakeoff contamination 

check, as defined in paragraph (c)(4) of 
this section, determines that the 
wings, control surfaces, and other crit-
ical surfaces, as defined in the certifi-
cate holder’s program, are free of frost, 
ice, or snow. 

(ii) It is otherwise determined by an 

alternate procedure approved by the 
Administrator in accordance with the 
certificate holder’s approved program 
that the wings, control surfaces, and 
other critical surfaces, as defined in 
the certificate holder’s program, are 
free of frost, ice, or snow. 

(iii) The wings, control surfaces, and 

other critical surfaces are redeiced and 
a new holdover time is determined. 

(4) Aircraft deicing/anti-icing proce-

dures and responsibilities, pretakeoff 
check procedures and responsibilities, 
and pretakeoff contamination check 
procedures and responsibilities. A pre-
takeoff check is a check of the air-
craft’s wings or representative aircraft 
surfaces for frost, ice, or snow within 
the aircraft’s holdover time. A pre-
takeoff contamination check is a check 
to make sure the wings, control sur-
faces, and other critical surfaces, as de-
fined in the certificate holder’s pro-
gram, are free of frost, ice, and snow. It 
must be conducted within five minutes 
prior to beginning take off. This check 
must be accomplished from outside the 
aircraft unless the program specifies 
otherwise. 

(d) A certificate holder may continue 

to operate under this section without a 

program as required in paragraph (c) of 
this section, if it includes in its oper-
ations specifications a requirement 
that, any time conditions are such that 
frost, ice, or snow may reasonably be 
expected to adhere to the aircraft, no 
aircraft will take off unless it has been 
checked to ensure that the wings, con-
trol surfaces, and other critical sur-
faces are free of frost, ice, and snow. 
The check must occur within five min-
utes prior to beginning takeoff. This 
check must be accomplished from out-
side the aircraft. 

[Doc. No. 6258, 29 FR 19222, Dec. 31, 1964, as 
amended by Amdt. 121–231, 57 FR 44942, Sept. 
29, 1992; Amdt. 121–253, 61 FR 2615, Jan. 26, 
1996] 

§ 121.631

Original dispatch or flight re-

lease, redispatch or amendment of 
dispatch or flight release. 

(a) A certificate holder may specify 

any regular, provisional, or refueling 
airport, authorized for the type of air-
craft, as a destination for the purpose 
of original dispatch or release. 

(b) No person may allow a flight to 

continue to an airport to which it has 
been dispatched or released unless the 
weather conditions at an alternate air-
port that was specified in the dispatch 
or flight release are forecast to be at or 
above the alternate minimums speci-
fied in the operations specifications for 
that airport at the time the aircraft 
would arrive at the alternate airport. 
However, the dispatch or flight release 
may be amended en route to include 
any alternate airport that is within the 
fuel range of the aircraft as specified in 
§§ 121.639 through 121.647. 

(c) No person may allow a flight to 

continue beyond the ETOPS Entry 
Point unless— 

(1) Except as provided in paragraph 

(d) of this section, the weather condi-
tions at each ETOPS Alternate Airport 
required by § 121.624 are forecast to be 
at or above the operating minima for 
that airport in the certificate holder’s 
operations specifications when it 
might be used (from the earliest to the 
latest possible landing time); and 

(2) All ETOPS Alternate Airports 

within the authorized ETOPS max-
imum diversion time are reviewed and 
the flight crew advised of any changes 

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