Description

This article provides generalized guidance for flight crews when landing a transport-category aircraft with flaps failed in the up position, or at a lesser setting than normally used for landing. The information herein does not supplant type-specific guidance in a company's Standard Operating Procedures (SOPs), Flight Operations Manual (FOM), Quick Reference Handbook (QRH), or other official publications.

A number of malfunctions can cause flaps to fail in the up position or close to the up position. These include an asymmetric flap condition that causes the asymmetry sensors to stop flap movement. Other possible causes include hydraulic failure, electrical failure, or mechanical failure such as a broken jackscrew. A no-flap landing is usually considered an emergency due to significantly higher landing speeds, which require longer runways. The high landing speeds can also result in brake overheat or fire.

(SKYbrary photo by Thomas Young)

Techniques

Guidance in SOPs and emergency procedures checklists usually recommend a long, straight-in approach. This reduces workload and minimizes maneuvering the airplane in a configuration with a higher stall speed. For these same reasons, it's also a good idea to ask Air Traffic Control (ATC) for a straight-out missed approach in the event of a go-around.

QRH guidance for flap failure will normally include landing performance tables that provide the proper approach speeds and expected landing distances. Crews should make sure to compare the performance data with runway available, and consider alternate landing sites if necessary. The QRH may leave it up to the crew whether to declare an emergency. Doing so can provide extra margins of safety, such as rescue and firefighting services (RFFS) standing by in the event of a brake fire.

When flying an approach with inoperative flaps, crews will not make the usual configuration callouts during the approach, i.e., "flaps one," "flaps two," etc. As a result, they may not have the usual cues for lowering the landing gear. Good crew resource management (CRM) can become a defence against this hazard. For example, during the approach briefing, the pilot flying (PF) might say, "Because we are not on our usual landing profile, let's take care not to forget to lower the landing gear." Of course, the landing gear aural warning would alert the crew below a certain altitude, but this would require a go-around in an already stressful situation.

Another hazard with a non-standard approach profile is forgetting to slow to approach speed (Vapp). Crews in simulator training have been known to fly the entire no-flap approach at 210 knots or higher. This negates landing performance calculations, increases the risk of a runway overrun and/or brake fire, and, at best, results in a go-around. A good approach briefing as described above can serve as a safety net against this hazard.

With some aircraft, a no-flap approach flown on a standard three-degree glide path may trigger a "sink rate" alert from the Enhanced Ground Proximity Warning System (EGPWS). Here again, a good approach briefing that notes this possibility can prevent the resulting startle factor during a critical phase of flight.

The QRH may require landing with autothrottle/autothrust (AT) off. Even if the QRH does not mandate this, turning off AT could be a good technique, to prevent large undesired power reductions as the aircraft nears the ground.

If the aircraft is equipped with autobrakes, crews should consider whether to use them, and if used, which setting to use. Autobrake systems have selectable deceleration rates. The QRH or other operator guidance may specify autobrake settings. Maximum manual braking may result in shorter landing distances than with autobrakes. Depending on landing distance available, the risk of brake overheat must be weighed against the greater risk of runway overrun.

At a higher landing speed, without the drag created by flaps, the aircraft will have a tendency to float in ground effect. Excessive flare could cause ballooning, which could turn a stable approach into a dangerous unstable approach. Most QRH guidance will direct pilots to "fly" the aircraft all the way into the touchdown with minimal flare.

After landing, crews should check brake temperatures and request RFFS assistance if necessary. If brake fire appears imminent, crews should consider preparing for an emergency evacuation. With high brake temperatures, crews should also consider keeping the aircraft away from the gate area until brakes have cooled. RFFS may have better access to the aircraft if it's on a taxiway or runway rather than at a gate with other aircraft and equipment close by.