Boeing requests waiver to
avoid 787-10 certification delay
2 23 APRIL, 2018 - SOURCE: FLIGHT
DASHBOARD - BY: STEPHEN TRIMBLE
WASHINGTON DC
A software bug
that shut-down one engine on a GE Aviation-powered 787 last July has prompted
Boeing to ask the US Federal Aviation Administration to temporarily exempt the
787-10 from a safety requirement.
Boeing plans to certificate the
GEnx-1B-powered version of the 787-10 in September, but the fix for the
software bug won’t be ready until 20 December 2019, Boeing says in the filing.
In a separate interview with
FlightGlobal, GE says it plans to deliver the software update sooner.
Unless the FAA approves Boeing’s
exemption request, the delivery schedule for the GEnx-powered version of the
787-10 could be delayed, Boeing says. Boeing delivered the first Rolls-Royce
Trent 1000-TEN-powered 787-10 in March, but the first GEnx-1B-powered version
is to be delivered to United Airlines in September.
GE plans to fix the software bug
that caused the engine shutdown as part of a package of updates called the
“B200” software version, Boeing says. It could deliver the fix that
specifically addresses the engine shutdown problem earlier, but Boeing prefers
to keep it packaged with several other updates..
The software bug is related to
another safety problem with the GEnx-1B.
In certain, rare conditions,
tiny ice crystals blown high by atmospheric convection into the stratosphere
can form on blades and vanes within the GEnx-1B. R-R’s Trent engine family
seems immune from the problem, but accumulated ice crystals in the GEnx engine
can shed suddenly, causing an in-flight shutdown.
Two years ago, GE solved that
problem by introducing a software modification. If ice crystal icing (ICI)
conditions are detected, the software commands the variable inlet guide vanes –
a set of interior doors used to discard foreign object debris on takeoff or
landing – to open and eject the ice before it can enter the core of the engine.
That fix appears to be working,
but Boeing has found a new bug in the software used for opening the doors.
Last July, a 787 crew
encountered ICI conditions at 40,000ft, so commanded the engines to provide
power for two step climbs up to 42,000ft. During the climb, the left-hand
engine flamed-out, causing power to roll back. The engine’s electronic controls
recognized the problem and automatically activated the igniters for a relight.
The combustor re-lit within 2s and thrust was restored fully within 18s, Boeing
says.
“The root cause of this event is
the fact that ICI accommodation logic, as it’s currently certified, is
suspended with the application of climb power,” Boeing says.
GE’s software update will insert
logic to extend ICI protections at engine power levels up to climb at altitudes
over 35,000ft, Boeing says.
GE-powered versions of the 787-8
and 787-9 can continue flying under existing airworthiness certificates. The
787-10, however, is still wrapping up certification testing, so the
non-compliance presented by the known software plug requires Boeing to request
an exemption.
Trent troubles force Air
NZ 787-9s to make refueling stops
23
aPRIL, 2018 - SOURCE: FLIGHT
DASHBOARD - BY: GREG WALDRON - SINGAPORE
Air New Zealand’s
services to the United States and Japan have been affected by issues with some
of its Rolls-Royce Trent 1000 engines on its Boeing 787-9s.
“Weight restrictions included in
an FAA directive issued last week mean some Boeing 787-9 Dreamliner flights to
Asian destinations will be required to make refueling stops,” says the carrier.
Routes affected include Los
Angeles and Houston, services to Tokyo Haneda, and some trans-Tsasman and
Pacific island flights.
“Depending on en-route weather
conditions, some flights may not be able to depart with all the fuel they
require, prompting the need for the fuel stop. Over the weekend, 787-9 flights
made fuel stops at Sydney, Cairns, Darwin and Guam.”
David Morgan, chief operational
integrity and standards officer, offered a positive assessment of the stops:
“Having the flexibility to make a short fuel stop means we are more likely to
be able to take a full contingent of customers and cargo. The alternative would
see us potentially having to disappoint significant numbers of customers by
moving them to later flights. We are committed to doing everything possible to
avoid this, particularly during this busy school holiday travel period.”
Overall, 9000 passengers will be
impacted by the refueling stop issue, which the carrier says is less than 3% of
customers.
The carrier made the remarks in
its fourth R-R engine update since 14 April, when it said it was working
closely with the engine maker following a directive from EASA that detailed a
new inspection regime for Trent 1000 powerplants as part of the effort to
address intermediate pressure compressor blade durability. On 13 April, R-R had
disclosed that Package C engines, which are used on the 787, are subject to
greater scrutiny.
FligthMaps Analytics shows that
Air New Zealand operates its 787-9s to four Asia-Pacific destinations: Bali,
Singapore, Shanghai, and Tokyo. It also uses the type on its Auckland-Houston
service.
On 16 April, Air New Zealand
advised that nine of the Trent 1000 engines that power its Boeing 787-9s are
affected by a recent airworthiness directive that reduced the inspection
interval on certain compressor components.
One day later, the FAA said it
will limit 787-8s and -9s with affected engines from flying on extended
operations (ETOPS) routes longer than 140min flight time from the closest
diversion airport.
Ingen kommentarer:
Legg inn en kommentar
Merk: Bare medlemmer av denne bloggen kan legge inn en kommentar.