Performance improvement package for Next Generation models will allow Maersk Air to upgrade Faroe Islands flights

Boeing is studying a set of modifications to boost the short-field performance of its Next Generation 737 for restricted runways as well as improve its obstacle clearance and hot-and-high characteristics.

The company will conduct low-speed windtunnel tests of the package in August, but declines to provide details until the changes are scale-tested and refined. It adds that Maersk Air is one of a group of "several" operators to request the field-length performance improvement. The changes, if adopted, will also require flight testing and re-certification of lower stall speeds.

Maersk Air says it expects the upgrade to be available before the end of this year so it can replace its 737-500s with -700s on services to Vagar in the Faroe Islands, which has a short, 1,250m (4,100ft) runway. The airline is phasing out its 737-500s as part of a move to a single-type fleet of -700s.

The changes are expected to include flap setting detents for take-off and landing beyond the current maximum of 15° and 40° respectively. Modifications to the new four-piece leading edge slat and inboard Krueger flap are not expected to be included in the package, which will be retrofittable if cleared for development. The modification may also include drooping the aileron, which was increased in span by 0.5m (20in) as part of the redesign of the 737 wing which has a 25% larger area than the 737 Classic.

Schedule changes are also expected as part of the modification to the current design in which the leading-edge flaps extend with the flap control lever in any position from 1° to 40°. The leading-edge slats currently move to an extended position with a flap lever position from 1° to 5°, while the slats move to a full extend position with a flap lever position from 10° to 40°. The standard double-slotted Fowler flaps, both inboard and outboard, may also require strengthening as part of the proposed changes to counter increased airloads.



Source: Flight International