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Airworthiness Directives; Airbus Model
A310 and Model A300 B4–600, B4–
600R, C4–605R Variant F, and F4–600R
(Collectively Called A300–600) Series
Airplanes
AGENCY: Federal Aviation
Administration, DOT.
ACTION: Proposed rule; withdrawal.
SUMMARY: This action withdraws a
notice of proposed rulemaking (NPRM)
that proposed a new airworthiness
directive (AD), applicable to all Airbus
Model A310 and A300–600 series
airplanes. That action would have
required revising the airplane flight
manual (AFM) to provide the flightcrew
with procedures to maintain airplane
controllability in the event of an inflight
thrust reverser deployment. Since
the issuance of the NPRM, the Federal
Aviation Administration (FAA) has
issued another AD to require revising
the AFM to contain the text of the AFM
revisions that the NPRM would have
required to be inserted into the AFM.
Accordingly, the proposed rule is
withdrawn.
FOR FURTHER INFORMATION CONTACT: Dan
Rodina, Aerospace Engineer,
International Branch, ANM–116, FAA,
Transport Airplane Directorate, 1601
Lind Avenue, SW., Renton, Washington
98055–4056; telephone (425) 227–2125;
fax (425) 227–1149.
SUPPLEMENTARY INFORMATION: A
proposal to amend part 39 of the Federal
Aviation Regulations (14 CFR part 39) to
add a new airworthiness directive (AD);
applicable to all Airbus Model A310
and A300 B4–600, B4–600R, C4–605R
Variant F, and F4–600R (collectively
Changes in Left Ventricular Size During Parabolic Flights by Two-dimensional
Echocardiography and Level Set Method
C Corsi1, G Saracino1, C Lamberti1, S Cerutti2, O Bailliart3, B Cholley3, A Capderou4, P Vaida5,
EG Caiani2
1DEIS University of Bologna, Bologna, Italy
2Politecnico di Milano, Dipartimento di Bioingegneria, Milano, Italy
3CHU Lariboisière, Paris, France
4Université Paris Sud, UPRES EA 2397, CCML, Physiologie, Le Plessis Robinson, France
5Université Bordeaux 2, Médecine Aérospatiale, Bordeaux, France
Abstract
This study aims to evaluate changes on cardiac
chambers size, induced by gravitational stresses. During
parabolic flight, seven subjects underwent 2-D
transthoracic echocardiography at three different gravity
phases (1 Gz, 1.8 Gz, and 0 Gz). LV endocardial borders
were detected applying a semi-automatic segmentation
procedure based on level set methods. LV cavity area was
computed frame-by-frame for a whole cardiac cycle
during each gravity phase. Expected modifications in LV
area with different gravity were found: at 1.8 Gz, enddiastolic
(ED) and end-systolic (ES) areas were
significantly (p<0.05) reduced of 10.7±5.4% and
21.6±11.1% respectively, compared to 1 Gz values, while
they were increased of 11.2±5.4% and 11.1±6% during 0
Gz. Fractional area change was augmented of
20.9±29.1% at 1.8 Gz, while it remained unchanged at 0
Gz, compared with 1 Gz values. Furthermore, LV filling
due to atrial contraction was increased at 0 Gz of
39±35.6%.
1. Introduction
Acute variations in gravity (head-to-foot acceleration,
Gz) induce dramatic fluid shifts in the body, as a
consequence of changes in hydrostatic pressure gradients.
Sudden exposure to microgravity causes an acute shift in
fluid from the lower extremities toward the head and
thorax, altering central filling volumes and pressures,
resulting in significant cardiovascular effects [1,2]. These
modifications, together with changes in the sympathetic
activity (heart rate and inotropic status), influence left
ventricular (LV) dimensions and function. These
hemodynamic alterations [3] are responsible for many of
the consequences associated with post-flight orthostatic
intolerance in astronauts [1]. The comprehension of
cardiovascular phenomena in a simulated microgravity
environment is then crucial to investigate and understand
physiological and pathologic changes occurring in space.
Parabolic flights allow to carry out medical experiments
on human subjects under conditions of weightlessness,
complementing studies conducted on ground [4] and in
space.
Echocardiography is a noninvasive, widespread and
powerful diagnostic tool and because of its portability it
can be utilized during parabolic flights conducted on
specially configured aircraft. This imaging technique
allows the visualization of the heart chambers and their
modifications induced by gravitational stresses during
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