248 

14 CFR Ch. I (1–1–24 Edition) 

§ 121.705 

(5) The nature of the failure, mal-

function, or defect. 

(6) Identification of the part and sys-

tem involved, including available infor-
mation pertaining to type designation 
of the major component and time since 
overhaul. 

(7) Apparent cause of the failure, 

malfunction, or defect (e.g., wear, 
crack, design deficiency, or personnel 
error). 

(8) Whether the part was repaired, re-

placed, sent to the manufacturer, or 
other action taken. 

(9) Whether the aircraft was ground-

ed. 

(10) Other pertinent information nec-

essary for more complete identifica-
tion, determination of seriousness, or 
corrective action. 

(f) A certificate holder that is also 

the holder of a Type Certificate (in-
cluding a Supplemental Type Certifi-
cate), a Parts Manufacturer Approval, 
or a Technical Standard Order Author-
ization, or that is the licensee of a type 
certificate holder, need not report a 
failure, malfunction, or defect under 
this section if the failure, malfunction, 
or defect has been reported by it under 
§ 21.3 of this chapter or under the acci-
dent reporting provisions of 49 CFR 
part 830. 

(g) No person may withhold a report 

required by this section even though 
all information required in this section 
is not available. 

(h) When certificate holder gets addi-

tional information, including informa-
tion from the manufacturer or other 
agency, concerning a report required 
by this section, it shall expeditiously 
submit it as a supplement to the first 
report and reference the date and place 
of submission of the first report. 

[Doc. No. 6258, 29 FR 19226, Dec. 31, 1964, as 
amended by Doc. No. 8084, 32 FR 5770, Apr. 11, 
1967; Amdt. 121–72, 35 FR 18188, Nov. 28, 1970; 
Amdt. 121–143, 43 FR 22642, May 25, 1978; 
Amdt. 121–178, 47 FR 13316, Mar. 29, 1982; 
Amdt. 121–187, 50 FR 32375, Aug. 9, 1985; 
Amdt. 121–195, 53 FR 8728, Mar. 16, 1988; 
Amdt. 121–251, 60 FR 65936, Dec. 20, 1995; 
Amdt. 121–319, 70 FR 76979, Dec. 29, 2005; 
Amdt. 121–387, 87 FR 75846, Dec. 9, 2022] 

§ 121.705 Mechanical interruption 

summary report. 

Each certificate holder shall submit 

to the Administrator, before the end of 

the 10th day of the following month, a 
summary report for the previous 
month of: 

(a) Each interruption to a flight, un-

scheduled change of aircraft en route, 
or unscheduled stop or diversion from a 
route, caused by known or suspected 
mechanical difficulties or malfunctions 
that are not required to be reported 
under § 121.703. 

(b) The number of engines removed 

prematurely because of malfunction, 
failure or defect, listed by make and 
model and the aircraft type in which it 
was installed. 

(c) The number of propeller 

featherings in flight, listed by type of 
propeller and engine and aircraft on 
which it was installed. Propeller 
featherings for training, demonstra-
tion, or flight check purposes need not 
be reported. 

[Doc. No. 6258, 29 FR 19226, Dec. 31, 1964, as 
amended by Amdt. 121–10, 30 FR 10025, Aug. 
12, 1965; Amdt. 121–319, 70 FR 76979, Dec. 29, 
2005] 

§ 121.707 Alteration and repair re-

ports. 

(a) Each certificate holder shall, 

promptly upon its completion, prepare 
a report of each major alteration or 
major repair of an airframe, aircraft 
engine, propeller, or appliance of an 
aircraft operated by it. 

(b) The certificate holder shall sub-

mit a copy of each report of a major al-
teration to, and shall keep a copy of 
each report of a major repair available 
for inspection by, the representative of 
the Administrator who is assigned to 
it. 

§ 121.709 Airworthiness release or air-

craft log entry. 

(a) No certificate holder may operate 

an aircraft after maintenance, preven-
tive maintenance or alterations are 
performed on the aircraft unless the 
certificate holder, or the person with 
whom the certificate holder arranges 
for the performance of the mainte-
nance, preventive maintenance, or al-
terations, prepares or causes to be pre-
pared— 

(1) An airworthiness release; or 
(2) An appropriate entry in the air-

craft log.